Equalizer and equalizer compensation parameter searching method for active cable

Abstract

The present disclosure discloses an equalizer and an equalizer compensation parameter search method for an active cable, the equalizer for obtaining compensation parameters to improve signal transmission, comprising: a candidate low frequency gain compensation parameter determination unit for determining candidate low frequency gain compensation parameters; the reference voltage determining unit is used for determining high-speed signal reference voltage under the candidate low-frequency gain compensation parameters; the candidate high-frequency gain compensation parameter determining unit is used for determining candidate high-frequency gain compensation parameters matched with the candidate low-frequency gain compensation parameters under the high-speed signal reference voltage, and the target gain compensation parameter determining unit is used for determining the target high-frequency gain compensation parameters according to the candidate low-frequency gain compensation parameters and the candidate high-frequency gain compensation parameters matched with the candidate low-frequency gain compensation parameters. And determining a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matched with the target low-frequency gain compensation parameter. According to the scheme, the compensation range can be increased, and the problem that communication requirements cannot be met only by adjusting high-frequency gain parameters is avoided.

Description

Technical Field

[0001] The present disclosure generally relates to the field of active cable technology. More specifically, the present disclosure relates to an equalizer and an equalizer compensation parameter search method for an active cable. Background Art

[0002] Different types of multimedia data are often transmitted from a source device to a destination device via an interface cable such as a High Definition Multimedia Interface ("HDMI") cable. The data transmission over the interface cable may be constrained by multiple parameters, such as the pre-emphasis level, bit rate, and number of active channels used for an equalizer at the source device. Conventionally, these parameters are set to fixed values.

[0003] At present, the source is used to perform link training on the sink to solve the problem of uneven quality of high-speed signals output by the source and uneven quality of high-speed signals transmitted by the passive cable connecting the source and the sink, so that an optimal link can be established between the source and the sink to improve the transmission quality of high-speed signals. In order to solve the problem of transmission distance, active cables came into being. When high-speed signals are transmitted between active cables and the source, the above-described problem of high-speed signal transmission between the source and the sink connected by passive cables is also faced.

[0004] The active cable AOC TX will use the equalizer to make equalization compensation for the received high-speed signal. The adjustable parameters of the equalizer compensation include low-frequency gain and high-frequency gain, which correspond to the low-frequency signal compensation capability and high-frequency signal compensation capability of the high-speed signal respectively. The adjustable parameters of the equalizer compensation include low-frequency gain and high-frequency gain, which correspond to the low-frequency signal compensation capability and high-frequency signal compensation capability of the high-speed signal respectively. During HDMI2.1 Link Training, the Source will send a high-speed training sequence signal. When the TX module receives this training signal, it can use the EOM (Eye Opening Monitor, eye diagram detection) method to sample the vertical eye diagram and detect the eye diagram amplitude. The specific sampling method EOM search method is as follows: the sampling circuit can be used to sample the voltage value of the received signal. As long as the sampling frequency is higher than the signal rate and is not an integer multiple of the signal rate, each reference voltage is scanned step by step. After a period of sampling, for example, a total of T samples are taken, the eye diagram of the high-speed signal sent by the Source can be sampled. When the low-frequency gain parameter is fixed, the amplitude of the eye diagram is relatively stable. If the reference voltage is scanned from high to low, theoretically, the number of reference voltage sampling points near the amplitude will be more than the sampling points of the previous reference voltage, and the number of sampling points of the previous reference voltage should account for a small percentage of all sampling points. In this way, the reference voltage can be scanned from high to low, and the number of sampling points reaches a certain threshold value, such as Th1, and the reference voltage is considered to be the eye diagram amplitude voltage. After finding the eye diagram amplitude, adjust the high-frequency gain parameter, re-count the sampling points at the eye diagram amplitude voltage, so that the high-frequency gain parameter with the largest number of sampling points can be selected as the optimal high-frequency gain parameter under the low-frequency gain parameter.

[0005] Traditional detection method 1: Combined scanning threshold voltage level and compensation adjustment level. Although the compensation search range is expanded, the statistical time is too long. The timeout of HDMI2.1 Link Training is limited. If the search time is too long, the Sink training time will be too short and Training will fail. Traditional detection method 2: Fixed scanning threshold voltage level, only adjusting high-frequency compensation level. The compensation effect is not compatible with the situation of adding copper extension line and not adding copper extension line.

[0006] In view of this, there is an urgent need to provide a solution for active cable parameter equalization to ensure stable and efficient high-speed signal transmission between the source end and the active cable under various combinations. Summary of the invention

[0007] In order to at least solve one or more of the technical problems mentioned above, the present disclosure proposes a solution for active cable parameter equalization in multiple aspects.

[0008] In a first aspect, the present disclosure provides a module for active cable parameter equalization, comprising: a control unit, configured to stop high-speed signal transmission in response to determining that a compensation parameter search is required; a parameter processing unit, configured to perform a compensation parameter search and obtain target compensation parameters; and a configuration unit, configured to set the obtained target compensation parameters for improving high-speed signal transmission.

[0009] In one embodiment, the module further includes: a monitoring unit configured to monitor changes in a high-speed signal flag bit, and determine the need to perform a compensation parameter search based on the changes in the high-speed signal flag bit.

[0010] In another embodiment, the monitoring unit is further configured to monitor a low-speed signal, and determine the need to perform a compensation parameter search based on the low-speed signal.

[0011] In yet another embodiment, the target compensation parameters include: a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matching the target low-frequency gain compensation parameter.

[0012] In yet another embodiment, in performing a compensation parameter search, the parameter processing unit is further configured to: determine a candidate low-frequency gain compensation parameter; determine a high-speed signal reference voltage under the candidate low-frequency gain compensation parameter; determine a candidate high-frequency gain compensation parameter that matches the candidate low-frequency gain compensation parameter under the high-speed signal reference voltage, and determine a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter that matches the candidate low-frequency gain compensation parameter based on the candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter that matches the candidate low-frequency gain compensation parameter.

[0013] In a second aspect, the present disclosure provides a cable plug, comprising: a signal receiving module, a signal improving module and a signal sending module; wherein the signal receiving module is used to receive a first high-speed signal; the signal improving module, which includes the module described in the first aspect above, is used to improve the first high-speed signal to obtain a second high-speed signal; the signal sending module is used to output the second high-speed signal.

[0014] In the third aspect, the present disclosure provides a method for active cable link training, which uses the module described in the first aspect to search for compensation parameters. After obtaining the target compensation parameters, the transmitting end sends a high-speed signal improved according to the target compensation parameters to the receiving end to complete the link training of the active cable.

[0015] In one embodiment, the output end connected to the receiving end uses the output of the transmitting end and completes the link training together with the input end connected to the transmitting end.

[0016] In another embodiment, performing a compensation parameter search to obtain a target compensation parameter includes: obtaining the performance of the output end by reading data in a register of the output end; performing a compensation parameter search based on the performance of the output end until an optimal parameter that meets a predetermined range is found, and determining the optimal parameter as the target compensation parameter.

[0017] In a fourth aspect, the present disclosure provides an active cable, comprising: an optical cable for transmitting signals, and the module as described in the first aspect above, for performing link training according to the method described in the third aspect above.

[0018] In a fifth aspect, the present disclosure provides an active cable, comprising a transmitting end module, a receiving end module and an optical cable; the transmitting end module is used to couple with a source end through a high-speed signal line and a low-speed signal line, and convert a received first high-speed electrical signal into an optical signal; the optical cable is used to transmit the optical signal emitted by the transmitting end module to the receiving end module; the receiving end module is used to couple with a destination end, and convert the received optical signal into a second high-speed electrical signal and provide it to the destination end; after power-on, the transmitting end module monitors the low-speed signal line, and in response to detecting that the source end starts link training on the low-speed signal line and high-speed signal transmission occurs on the high-speed signal line, stops converting the first high-speed signal into an optical signal, the transmitting end module performs link training with the source end, and searches for target parameters during the link training process; and compensates the received first high-speed electrical signal with the searched target parameter, generates an optical signal according to the compensated first high-speed electrical signal, and outputs the optical signal to the receiving end module; the source end and the destination end continue to perform the link training through the active cable and complete the link training.

[0019] In a sixth aspect, the present disclosure provides an active cable, comprising a transmitting end module, a receiving end module and a transmission cable;

[0020] The transmitting end module is used to couple with the source end through the high-speed signal line and the low-speed signal line; the transmission cable is used to transmit the high-speed signal sent by the transmitting end module to the receiving end module; the receiving end module is used to couple with the destination end, receive the high-speed electrical signal and provide it to the destination end; after the transmitting end module is powered on, it monitors the low-speed signal line, and in response to detecting that the source end starts link training on the low-speed signal line and high-speed signal transmission occurs on the high-speed signal line, stops transmitting the high-speed signal, and the transmitting end module performs link training with the source end and searches for target parameters during the link training process; and compensates the received first high-speed electrical signal with the searched target parameter, generates a second high-speed electrical signal according to the compensated first high-speed electrical signal, and outputs the second high-speed electrical signal to the receiving end module; the source end and the destination end continue to perform the link training through the active cable and complete the link training.

[0021] In one embodiment, the target parameters include a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matching the target low-frequency gain compensation parameter; the target low-frequency gain compensation parameter is used to compensate for the low-frequency component of the first high-speed electrical signal received by the transmitting end module; the target high-frequency gain compensation parameter is used to compensate for the high-frequency component of the first high-speed electrical signal received by the transmitting end module.

[0022] In another embodiment, the sending end module is connected to the source end via one or more copper wire extension lines.

[0023] In another embodiment, the search target parameter includes: determining a candidate low-frequency gain compensation parameter; determining a reference voltage level k corresponding to an eye diagram amplitude under the candidate low-frequency gain compensation parameter, wherein when using a boundary value within an adjustment range of the candidate low-frequency gain compensation parameter and a high-frequency gain parameter, the number of sampling points obtained by sampling the first high-speed electrical signal with the reference voltage level k is count1, and count1 is greater than a first threshold; searching for an optimal high-frequency gain compensation parameter within the adjustment range of the high-frequency gain parameter, and recording the number of sampling points obtained by sampling the first high-speed electrical signal with the reference voltage level k when using the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter as count2; and determining the compensation parameter based on whether count2-count1 is greater than a second threshold.

[0024] In yet another embodiment, if count2 - count1 is greater than a second threshold Th2, determine that the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter are the target parameters found; if count2 - count1 is not greater than the second threshold Th2, then perform the process of searching for the target parameters again, wherein, in the process of performing the search for the target parameters again, determine another low-frequency gain compensation parameter as the candidate low-frequency gain compensation parameter.

[0025] In yet another embodiment, the determining another low-frequency gain compensation parameter as the candidate low-frequency gain compensation parameter includes:

[0026] Within the adjustment range of the low-frequency gain compensation parameter, select a low-frequency gain compensation parameter one by one in ascending order and determine it as the candidate low-frequency gain compensation parameter.

[0027] In yet another embodiment, the adjustment range of the low-frequency gain compensation parameter is {M1, M2}, M1 < M2, where the selection of M1 satisfies (Q1 - P1) = S1, the selection of M2 satisfies (Q1 - P2) = S2, and where {P1, P2} is the compensation ability corresponding to {M1, M2}, Q1 is the compensation ability corresponding to the high-frequency maximum compensation gear parameter of the high-frequency gain compensation parameter, and {S1, S2} is the estimated high-frequency attenuation range of the copper wire extension connecting the sending module and the source end.

[0028] In yet another embodiment, the determining the reference voltage gear k corresponding to the eye diagram amplitude under the candidate low-frequency gain compensation parameter includes: within the adjustment range of the high-speed signal reference voltage, select a reference voltage, sample the first high-speed electrical signal with the selected reference voltage, and obtain the number of sampling points as C[k], where k represents the selected reference voltage gear; by selecting different reference voltages until a reference voltage gear k is found such that C[k] > Th1, then record Count1 = C[k], where Th1 is the first threshold.

[0029] In yet another embodiment, the adjustment range of the high-frequency gain parameter is {L1, L2}, L1 < L2, where the selection of L1 satisfies Q1 - P1 = S1, the selection of L2 satisfies Q2 - P1 = S2, and where {Q1, Q2} is the compensation ability corresponding to {L1, L2}, P1 is the low-frequency signal compensation ability corresponding to the low-frequency maximum compensation gear of the high-frequency gain compensation parameter, and {S1, S2} is the estimated high-frequency attenuation range of the copper wire extension connecting the sending module and the source end.

[0030] In yet another embodiment, the adjustment range of the high-speed signal reference voltage is {R1, R2}, where R1 < R2, and the adjustment range of the high-speed signal reference voltage covers {0 mV, TXSwingmax}, and TXSwingmax is the maximum value of the eye diagram amplitude.

[0031] In yet another embodiment, within the adjustment range of the high-speed signal reference voltage, an initial reference voltage is set to R2, and the first high-speed electrical signal is sampled in descending order to obtain the number of sampling points.

[0032] In yet another embodiment, within the adjustment range of the high-speed signal reference voltage, a reference voltage is selected using the binary search method, and the first high-speed electrical signal is sampled with the selected reference voltage to obtain the number of sampling points.

[0033] In yet another embodiment, within the adjustment ranges of all low-frequency compensation parameters and high-frequency gain parameters, if Count2 - Count1 is always not greater than the second threshold Th2, then the low-frequency compensation gain parameter and the high-frequency gain parameter are set to default values.

[0034] In a seventh aspect, the present disclosure provides an equalizer for obtaining compensation parameters to improve signal transmission, characterized by comprising:

[0035] A candidate low-frequency gain compensation parameter determination unit for determining candidate low-frequency gain compensation parameters;

[0036] A reference voltage determination unit for determining the high-speed signal reference voltage under the candidate low-frequency gain compensation parameters;

[0037] A candidate high-frequency gain compensation parameter determination unit for determining candidate high-frequency gain compensation parameters that match the candidate low-frequency gain compensation parameters under the high-speed signal reference voltage, and

[0038] A target gain compensation parameter determination unit for determining target low-frequency gain compensation parameters and target high-frequency gain compensation parameters that match them according to the candidate low-frequency gain compensation parameters and the candidate high-frequency gain compensation parameters that match them.

[0039] In one embodiment, the candidate low-frequency gain compensation parameter determination unit is configured to:

[0040] Within the adjustment range of the low-frequency gain compensation parameter, a low-frequency gain compensation parameter is selected one by one in ascending order and determined as the candidate low-frequency gain compensation parameter.

[0041] In yet another embodiment, the adjustment range of the low-frequency gain compensation parameter is determined according to the attenuation of the extension line of the active cable and the value of the low-frequency gain compensation parameter at each gear position.

[0042] In yet another embodiment, the reference voltage determination unit is configured as:

[0043] Within the adjustment range of the high-speed signal reference voltage, a reference voltage is selected in descending order, and the number of high-speed signal sampling points of the reference voltage is counted when the minimum value of the high-frequency gain compensation parameter adjustment range is reached, until a reference voltage whose number of high-speed signal sampling points is greater than a first threshold value Th1 is found, and it is determined as the high-speed signal reference voltage under the candidate low-frequency gain compensation parameter.

[0044] In yet another embodiment, the adjustment range of the high-speed signal reference voltage is determined according to the amplitude range of the active cable and the attenuation of the extension line.

[0045] In yet another embodiment, the candidate high frequency gain compensation parameter determination unit is configured as follows:

[0046] A high-frequency gain compensation parameter is selected one by one in order from small to large, and the number of high-speed signal sampling points under each high-frequency gain compensation parameter is counted, and the high-frequency gain compensation parameter with the largest number of high-speed signal sampling points is used as a candidate high-frequency gain compensation parameter that matches the candidate low-frequency gain compensation parameter.

[0047] In yet another embodiment, the adjustment range of the high frequency gain compensation parameter is determined based on the candidate low frequency gain compensation parameter, and the combination of the high frequency gain compensation parameter and the candidate low frequency gain compensation parameter supports offsetting the extended line attenuation.

[0048] In yet another embodiment, the target gain compensation parameter determination unit is configured as follows:

[0049] Counting the number of high-speed signal sampling points of the high-speed signal reference voltage when the high-frequency gain compensation parameter adjustment range is the minimum value under the candidate low-frequency gain compensation parameter, count1, and the number of high-speed signal sampling points of the high-speed signal reference voltage under the matching candidate high-frequency gain compensation parameter, count2;

[0050] Determine the first candidate low-frequency gain compensation parameter whose count2-count1 is greater than the second threshold Th2 as the target low-frequency gain compensation parameter, and determine the candidate high-frequency gain compensation parameter matched thereto as the target high-frequency gain compensation parameter; and

[0051] When count2-count1 is less than or equal to the second threshold Th2 under all candidate low-frequency gain compensation parameters, the default values ​​are set as the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter.

[0052] In yet another embodiment, the default value is an empirical value that satisfies the extension line attenuation compensation.

[0053] In an eighth aspect, the present disclosure provides a method for searching compensation parameters, characterized by comprising:

[0054] determining candidate low frequency gain compensation parameters;

[0055] Determining a high-speed signal reference voltage under the candidate low-frequency gain compensation parameters;

[0056] determining a candidate high frequency gain compensation parameter that matches the candidate low frequency gain compensation parameter at the high speed signal reference voltage, and

[0057] According to the candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter, a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter are determined.

[0058] In a ninth aspect, the present disclosure provides an equalizer compensation parameter search method for an active cable, the active cable comprising a transmitting end module, a receiving end module and a cable;

[0059] The transmitting end module is used to couple with the source end through a high-speed signal line and a low-speed signal line;

[0060] The cable is used to transmit the electrical signal sent by the sending end module to the receiving end module;

[0061] The receiving end module is used to couple with the destination end, and provide the received second high-speed electrical signal to the destination end;

[0062] The transmitting end module includes the equalizer, and the equalizer is used to compensate the first high-speed electrical signal according to the compensation parameter;

[0063] The method comprises:

[0064] In response to the transmitting end module being powered on, monitoring the low-speed signal line;

[0065] In response to detecting that the source end starts link training on the low-speed signal line and high-speed signal transmission occurs on the high-speed signal line, searching for a target parameter;

[0066] The search target parameters include:

[0067] determining candidate low frequency gain compensation parameters;

[0068] Determine the reference voltage level k corresponding to the eye diagram amplitude under the candidate low-frequency gain compensation parameter, where when using the boundary values within the adjustment range of the candidate low-frequency gain compensation parameter and the high-frequency gain parameter, the number of sampling points obtained by sampling the first high-speed signal with the reference voltage level k is count1, and count1 is greater than the first threshold;

[0069] Search for the optimal high-frequency gain compensation parameter within the adjustment range of the high-frequency gain parameter, and record that when using the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter, the number of sampling points obtained by sampling the first high-speed signal with the reference voltage level k is count2;

[0070] Determine the compensation parameter according to whether count2 - count1 is greater than the second threshold.

[0071] In one embodiment, an equalizer compensation parameter search method for an active cable is characterized in that:

[0072] If count2 - count1 is greater than the second threshold Th2, determine the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter as the searched target parameters;

[0073] If count2 - count1 is not greater than the second threshold Th2, then perform the process of searching for the target parameter again, where in the process of performing the process of searching for the target parameter again, determine another low-frequency gain compensation parameter as the candidate low-frequency gain compensation parameter.

[0074] In another embodiment, determining another low-frequency gain compensation parameter as the candidate low-frequency gain compensation parameter includes:

[0075] Within the adjustment range of the low-frequency gain compensation parameter, select a low-frequency gain compensation parameter one by one in ascending order and determine it as the candidate low-frequency gain compensation parameter.

[0076] In another embodiment, the adjustment range of the low-frequency gain compensation parameter is {M1, M2}, M1 < M2, where the selection of M1 satisfies (Q1 - P1) = S1, the selection of M2 satisfies (Q1 - P2) = S2, and where {P1, P2} is the compensation ability corresponding to {M1, M2}, Q1 is the compensation ability corresponding to the high-frequency maximum compensation level parameter of the high-frequency gain compensation parameter, and {S1, S2} is the estimated high-frequency attenuation range of the copper wire extension connecting the transmitting end module and the source end.

[0077] In another embodiment, determining the reference voltage level k corresponding to the eye diagram amplitude under the candidate low-frequency gain compensation parameter includes:

[0078] Within the adjustment range of the high-speed signal reference voltage, select a reference voltage, and sample the first high-speed signal with the selected reference voltage to obtain the number of sampling points C[k], where k represents the selected reference voltage level; by selecting different reference voltages until a reference voltage level k is found such that C[k] > Th1, then record Count1 = C[k], where Th1 is the first threshold value.

[0079] In yet another embodiment, the search range for the high-speed compensation parameter levels is {L1, L2}, where L1 < L2, and the selection of L1 satisfies Q1 - P1 = S1, the selection of L2 satisfies Q2 - P1 = S2, and where {Q1, Q2} is the compensation ability corresponding to {L1, L2}, P1 is the low-frequency signal compensation ability corresponding to the low-frequency maximum compensation level of the high-frequency gain compensation parameter, and {S1, S2} is the estimated high-frequency attenuation range of the copper wire extension connecting the transmitting end module and the source end.

[0080] In yet another embodiment, the adjustment range of the reference voltage is {R1, R2}, where R1 < R2, and the reference voltage range covers {0 mV, TXSwingmax}, and TXSwingmax is the maximum value of the eye diagram amplitude.

[0081] In yet another embodiment, within the adjustment range of the high-speed signal reference voltage, set the initial reference voltage to R2, and sample the first high-speed signal in descending order to obtain the number of sampling points.

[0082] In yet another embodiment, within the adjustment range of the high-speed signal reference voltage, use the binary search method to select a reference voltage, and sample the first high-speed signal with the selected reference voltage to obtain the number of sampling points.

[0083] In yet another embodiment, within the adjustment range of all low-frequency compensation parameters and the search range of high-speed compensation parameter levels, if Count2 - Count1 is always not greater than the second threshold Th2, then set the low-frequency compensation gain parameter and the high-frequency gain parameter to the default values.

[0084] Compared with the prior art, the present invention has at least the following beneficial effects:

[0085] 1. By performing link training on the source end and the transmitting end of the active cable, during the link training process, obtain the target compensation parameters through the module for active cable parameter equalization to improve the high-speed signal. Then, transmit the high-speed signal with better signal quality after improvement to the destination end, and the destination end uses the received improved high-speed signal to perform link training with the source end, which can shorten the link training time;

[0086] 2. When searching for compensation parameters using the module for active cable parameter equalization, turning off high-speed signal transmission can avoid the erroneous start of the compensation parameter algorithm and prevent the uncompensated high-speed signal from being transmitted to the receiving end, causing the failure of link training between the receiving end and the destination end;

[0087] 3. The need for compensation parameter search is determined by the change of the high-speed signal flag, which improves the accuracy of monitoring and avoids the error caused by the delay in starting the compensation parameter algorithm;

[0088] 4. The compensation parameters include low-frequency gain compensation parameters and high-frequency gain compensation parameters, which can increase the compensation range and avoid the problem that the high-speed signal quality is seriously attenuated in long-distance transmission and connected through extension lines, and only adjusting the high-frequency gain parameters cannot meet the communication requirements;

[0089] 5. During the compensation parameter search process, the low-frequency gain compensation parameter is first fixed and then the high-frequency gain compensation parameter matching it is searched. Based on the adjustment range of the low-frequency component of the high-speed signal, the compensation demand of the high-frequency component of the high-speed signal can be determined, thereby quickly and accurately compensating the high-frequency component of the high-speed signal;

[0090] 6. By confirming the adjustment range of the low-frequency gain compensation parameters, the search time for candidate low-frequency gain compensation parameters is reduced, further shortening the link training time;

[0091] 7. Traverse all reference voltages in a combined manner, use the reference voltage to sample the high-speed signal to obtain the number of sampling points, and obtain the compensation parameters based on the number of sampling points, so that the screened compensation parameters are more complete and the efficiency of screening the compensation parameters is higher;

[0092] 8. A link training method is proposed, in which the active cable transmitter performs parameter compensation after receiving the high-speed signal, and stops the high-speed signal transmission during the parameter compensation process. Then, the active cable transmitter outputs the optimized high-speed signal to the destination end, and the destination end uses the optimized high-speed signal to perform link training with the source end, thereby shortening the link training time.

[0093] 9. According to the differential amplitude range of the active cable high-speed signal and the signal attenuation range of the extension line, the search range of the amplitude reference voltage, the search range of the high-frequency gain and the search range of the low-frequency gain are optimized, so that the compensation parameter search time is reduced and the compatibility of the system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0095] Figure 1 An exemplary structural block diagram of a module for active cable parameter equalization according to an embodiment of the present disclosure is shown;

[0096] Figure 2 An exemplary flow chart of a method for searching compensation parameters according to an embodiment of the present disclosure is shown;

[0097] Figure 3 An exemplary structural block diagram of a cable plug according to an embodiment of the present disclosure is shown;

[0098] Figure 4 An exemplary flow chart of the method for active cable link training according to an embodiment of the present disclosure is shown;

[0099] Figure 5 An exemplary structural block diagram of a first active cable according to an embodiment of the present disclosure is shown;

[0100] Fig. 6A An exemplary structural block diagram of a second active cable according to an embodiment of the present disclosure is shown;

[0101] Figure 6B An exemplary structural block diagram of a second active cable with a copper wire extension line added according to an embodiment of the present disclosure is shown;

[0102] Figure 7 An exemplary flow chart of a method for searching equalizer compensation parameters for an active cable according to an embodiment of the present disclosure is shown;

[0103] Figure 8 An exemplary flow chart of the equalizer compensation parameter search method according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0104] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0105] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0106] It should also be understood that the terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used in this disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in this disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.

[0107] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0108] The specific implementation of the present disclosure is described in detail below with reference to the accompanying drawings.

[0109] Exemplary application scenarios

[0110] As people's living standards improve, the need for obtaining high-definition video signals has become an increasing demand. In order to meet this growing demand, the High Definition Multimedia Interface (HDMI) technology has been continuously evolving. HDMI 2.1 is one of the latest HDMI standards. HDMI 2.1 supports data transmission speeds up to 48Gbps, which is more than four times higher than the previous standard (HDMI 2.0). It also has higher resolution, refresh rate and dynamic HDR features. In the Fixed Rate Link (FRL) mode supported by HDMI2.1, link training is required when the source and sink establish a link for the first time, and link training is also required to update the FRL rate. The first link training will go through four link training states in sequence. When entering the third link training state (LTS:3), the source will send different high-speed training signal sequences to train the equalizer of the sink according to the selected rate and other parameters.

[0111] At the same time, the new digital video interface standard DP 1.4 also demonstrates its powerful performance in the field of video transmission. The new digital video interface standard DP 1.4 will support 5120×2880@60Hz with high dynamic range, and up to 8K (7680×4320)@60Hz using 4-2-0 pixel structure in high dynamic range and standard mode. The information transmission between the source and the destination of DP (DisplayPort) is realized by reading and writing the DP (DisplayPort) configuration data (DPCD) register on the destination. By reading specific registers in DPCD, the source will know the performance of the destination. When establishing a data link, that is, during link training, the source writes to DPCD to indicate the configuration of the target link, and the destination also writes the results of each link training stage here.

[0112] However, when using HDMI active cable or DP active cable to transmit high-speed signals, the electrical signal may be interrupted during the transmission process. When the active cable uses AOC (Active Optical Cable, "AOC"), after the active cable TX (Transmitter, sending end) module receives the electrical signal, it converts the electrical signal into an optical signal through the electro-optical conversion chip, and transmits the optical signal in the AOC. After the active cable RX (Receiver, receiving end) module receives the optical signal, it converts the optical signal back into an electrical signal through the photoelectric conversion chip and transmits it to the destination (sink). The quality of the high-speed signal received in the AOC is severely attenuated due to the introduction of the copper wire between the source and TX. However, the electrical signal is interrupted in the active cable and is not directly transmitted to the destination (sink). When the active cable uses ACC (Active Copper Cable), the electrical signal is directly transmitted to the destination (sink) after compensation amplification in the TX / RX module. The use of a copper extension cable between the AOC / ACC and the Sink / Source will make the high-speed signal attenuation more serious. Thus, the quality of the high-speed signal being transmitted is affected.

[0113] Specifically, the HDMI2.1 protocol stipulates that in the Fixed Rate Link (FRL) mode supported by HDMI2.1, link training is required when the source and sink establish a link for the first time, and link training is also required to update the FRL rate. For specific link training status, see Table 1:

[0114] Table 1 HDMI2.1 protocol link training status

[0115]

[0116]

[0117] As shown in Table 1, in the LTS:2 state of link training, the sink instructs the source to start link training. In the LTS:3 state, the source will send a corresponding high-speed training sequence according to the selected rate and other parameters. All link training processes include state transitions, training control, and interaction of training states. During the link training process, the source sends a training sequence to the sink. If the sink can correctly parse the training sequence after receiving it, the link training is considered successful. Otherwise, the link training fails. If an unimproved high-speed signal is transmitted to the sink, the sink may not be able to correctly identify the training signal due to poor signal quality, resulting in incorrect signal recognition when the link training is in the LTS:3 state, and the sink cannot enter the LTS:P state correctly.

[0118] During use, in order to avoid repeated plugging and unplugging of the source end, causing damage to the source end interface, an extension line will be added to the source end. At the same time, in the fields of medical and vision, since the source end (source) and the destination end (sink) are located inside or are specially required, an extension line will be added to the source end (source). Since the quality of high-speed signals may vary, especially when an extension line is added to the source end (source), the signal quality will be further attenuated. Therefore, the electrical receiving module in the TX module is usually equipped with an equalizer to compensate for the received signal. However, there is currently a lack of effective parameter compensation solutions for the equalizer at the TX end of the active cable, especially when a copper wire extension line is used.

[0119] Exemplary scheme for active cable parameter equalization

[0120] In view of this, the presently disclosed embodiment provides a solution for active cable parameter equalization, which improves high-speed signal transmission by performing compensation parameter search, obtaining target compensation parameters, and setting the obtained target compensation parameters, thereby ensuring stable and efficient high-speed signal transmission between the destination end and the active cable in various combinations.

[0121] Figure 1 An exemplary structural block diagram of a module 100 for active cable parameter equalization according to an embodiment of the present disclosure is shown.

[0122] like Figure 1As shown, the module 100 may include a control unit 110, a parameter processing unit 120, a configuration unit 130 and a monitoring unit 140. Specifically, the monitoring unit 140 is used to determine whether a compensation parameter search is required. The parameter processing unit 120 is used to search for compensation parameters and obtain target compensation parameters. The input end of the configuration unit 130 is connected to the output end of the parameter processing unit 120 and the output end of the monitoring unit 140, and the configuration unit 130 is used to set the obtained target compensation parameters for improving high-speed signal transmission. The input end of the control unit 110 is connected to the output end of the configuration unit 130, and the control unit 110 is configured to stop high-speed signal transmission in response to determining that a compensation parameter search is required, and receive the high-speed signal improved by the configuration unit 130. It should be noted that the aforementioned connection is a virtual connection, including a direct connection and an indirect connection. The control unit 110, the parameter processing unit 120, the configuration unit 130 and the monitoring unit 140 can be integrated in an integrated circuit, or they can be connected as independent units.

[0123] Specifically, the active cable may include a transmitting end, a receiving end, and a cable. The transmitting end is coupled to a source end source, the receiving end is coupled to a destination end sink, and the cable is used to transmit a signal sent by the transmitting end to the receiving end. The module 100 is arranged in the transmitting end. The transmitting end may be directly connected to the source end, or may be connected to the source end through an extension line.

[0124] In one embodiment, the active cable may include but is not limited to a DisplayPort (“DP”) active cable and a High Definition Multimedia Interface (“HDMI”) active cable. The active cable may include but is not limited to an AOC cable and an ACC cable.

[0125] In one embodiment, the control unit 110 is connected to a cable, and is configured to stop high-speed signal transmission in response to determining that a compensation parameter search is required, and transmit the received high-speed signal improved by the configuration unit 130 to the receiving end through the cable. Specifically, the control unit 110 can use a central processing unit (CPU), a microcontroller unit (MCU), a switch circuit, etc. to stop the sending end from transmitting high-speed signals. In order to prevent the uncompensated high-speed signal from being transmitted to the receiving end, causing the link training to fail, the control unit 110 will stop the sending end from transmitting high-speed signals before searching for compensation parameters. At this time, the training sequence of the source end will not be transmitted to the receiving end temporarily. When the control unit 110 receives the high-speed signal improved by the configuration unit 130, it transmits the improved high-speed signal to the receiving end through the cable.

[0126] Specifically, when the active cable used is an AOC (Active Optical Cable) that uses optical fiber for signal transmission, the control unit 110 stops converting the high-speed electrical signal received by the sending end into an optical signal; when the active cable used is an ACC (Active copper cable) that uses copper wire for signal transmission, the control unit 110 stops the sending end from transmitting the high-speed electrical signal emitted by the source end to the receiving end.

[0127] By stopping the high-speed signal transmission during the compensation parameter search process, the compensation parameter algorithm can be prevented from being falsely started, and the uncompensated high-speed signal can be prevented from being transmitted to the receiving end, causing the failure of link training.

[0128] In one embodiment, the parameter processing unit 120 is coupled to the source end source, which is used to search for compensation parameters and obtain target compensation parameters. Specifically, the parameter processing unit 120 performs link training with the source end source according to the sequence for link training sent by the source end source, and searches for compensation parameters during the link training process to obtain target compensation parameters. The target compensation parameters include: a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter that matches it. The target low-frequency gain compensation parameter corresponds to the low-frequency component compensation capability of the high-speed signal. The target high-frequency gain compensation parameter corresponds to the high-frequency component compensation capability of the high-speed signal. It can be understood that the parameter processing unit 120 is coupled to the source end in a virtual connection relationship, that is, the parameter processing unit 120 can obtain the data sent by the source end. Specifically, the parameter processing unit can be directly connected to the source end, or it can be indirectly connected to the source end through other means such as copper wires.

[0129] By respectively obtaining the target low-frequency gain compensation parameters and the matching target high-frequency gain compensation parameters, the compensation range can be increased, which solves the problem that the high-speed signal attenuation is serious in the scenarios where ACC active cables are used for long-distance transmission and copper wire extension cables are added between the source and the transmitter, and only adjusting the high-frequency gain parameters cannot meet the communication requirements.

[0130] In one embodiment, the configuration unit 130 is used to set the target compensation parameters obtained by the parameter processing unit 120 to improve the high-speed signal transmission. Specifically, the configuration unit 130 may include a microcontroller ("MCU"). In some embodiments, the microcontroller may be independently placed outside the integrated circuit or built into the integrated circuit, and sends the improved high-speed signal to the control unit 110, and the control unit 110 sends the received improved high-speed signal to the receiving end through a cable.

[0131] In one embodiment, the monitoring unit 140 is coupled to the source end source, and the monitoring unit 140 is configured to monitor the change of the high-speed signal flag bit, and determine the need for compensation parameter search based on the change of the high-speed signal flag bit. Specifically, when the monitoring unit 140 monitors that the high-speed signal flag bit changes from 1 to 0, it indicates that the high-speed signal changes from non-existent to existing. Thus, the monitoring unit monitors the presence of a high-speed signal. At this time, it is determined that a compensation parameter search is required, the control unit 110 stops the transmitting end from transmitting the high-speed signal, and the parameter processing unit 120 performs link training with the source end source according to the sequence for link training sent by the source end source, and performs compensation parameter search during the link training process.

[0132] Further, the monitoring unit 140 may also be configured to monitor the low-speed signal, and determine the need to perform compensation parameter search based on the low-speed signal. Specifically, the monitoring unit 140 detects and confirms the link training status information between the source end source and the transmitting end by monitoring the low-speed signal, and confirms whether to perform compensation parameter search during the link training process based on the link training status information.

[0133] Specifically, the low-speed signal is an IIC signal or an AUX signal. The IIC signal is a low-speed signal used when the active cable used is an HDMI active cable, and the AUX signal is a low-speed signal used when the active cable used is a DP active cable. Since the source end source and the transmitting end exchange information through the IIC signal or the AUX signal, the monitoring unit 140 can obtain the link training status information between the source end source and the transmitting end by monitoring low-speed signals such as IIC or AUX. The link training status information includes whether the link training has started, whether the link training is successful, whether the source end source is ready for link training, etc. By monitoring low-speed signals such as IIC or AUX, it can be ensured that in a complex physical link in reality, before the source end source and the transmitting end communicate normally, the state of the parameter processing unit 120 is consistent with the state of the link training, and the compensation parameter algorithm will not be mistakenly started to cause the link training to fail.

[0134] By monitoring the low-speed signal and detecting the source end source to start link training, and when the high-speed signal flag changes from 1 to 0, the parameter processing unit 120 performs link training with the source end source. The monitoring accuracy is improved, and the error caused by the delay in starting the compensation parameter algorithm is avoided. It can be avoided that when only the low-speed signal is monitored, the link training is started before the high-speed signal is detected, and the result of the link training at this time is wrong, which will affect the result of the compensation parameter search.

[0135] In the prior art, the link training between the source end source and the destination end sink includes the following process: the source end source sends a high-frequency signal to the destination end sink, the source end source and the destination end sink exchange information, determine the key parameters such as the communication protocol, data format, and transmission rate that both parties can accept, and when the source end source and the destination end sink agree on these key parameters, the source end source sends a high-speed signal to the destination end sink. However, when a copper wire extension line is added between the source end source and the transmitting end or the quality of the high-speed signal sent from the source end to the destination end is seriously attenuated, the destination end sink needs to process a large amount of information, which causes the link training to time out when the source end and the destination end perform link training. For example, when an active cable using the HDMI2.1 protocol is used for high-speed signal transmission, the timeout of each link training of the protocol is 200ms. When the quality of the high-speed signal sent from the source end source to the destination end sink is seriously attenuated or a copper wire extension line is added between the source end and the transmitting end, the execution time of the link training between the source end and the destination end may exceed 200ms, resulting in link training failure, thereby affecting data transmission.

[0136] Based on the above problems in the prior art, the target compensation parameters are obtained by link training the source end source and the transmitting end to improve the high-speed signal. Specifically, when the monitoring unit 140 monitors the change of the high-speed signal flag, the control unit 110 stops the transmitting end from transmitting the high-speed signal, and the parameter processing unit 120 performs link training with the source end source according to the sequence for link training sent by the source end source. The parameter processing unit 120 searches for compensation parameters to obtain the target compensation parameters. And in the process of obtaining the target compensation parameters, considering the situation of adding a copper wire extension line between the source end and the transmitting end, the target low-frequency gain compensation parameters and the target high-frequency gain compensation parameters matching therewith are obtained respectively. The configuration unit 130 sets the target compensation parameters obtained by the parameter processing unit 120 for improving the high-speed signal. Then, the parameter processing unit 120 stops the compensation parameter search, and the control unit 110 starts the high-speed signal transmission of the transmitting end again, and transmits the improved high-speed signal with better signal quality to the receiving end. Then, the receiving end sends the improved high-speed signal with better signal quality to the destination end sink, and the destination end sink uses the received improved high-speed signal to perform link training with the source end source. Since the target compensation parameters are obtained by taking into account the case of adding a copper extension line between the source end and the sending end, and the high-speed signal is improved by using the target compensation parameters, a high-speed signal with better signal quality is obtained. Therefore, when the destination end sink uses the received high-speed signal with better signal quality to perform link training with the source end source, the high-speed signal attenuation is weak, which can ensure that the link training does not time out.

[0137] Figure 2 An exemplary flow chart of a compensation parameter search method 200 according to an embodiment of the present disclosure is shown.

[0138] like Figure 2 As shown, the parameter processing unit 120 adopts the compensation parameter search method 200 to obtain the target compensation parameter. In step S210, the candidate low-frequency gain compensation parameter is determined. In step S220, the high-speed signal reference voltage under the candidate low-frequency gain compensation parameter is determined. In step S230, the candidate high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter under the high-speed signal reference voltage is determined. In step S240, the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter are determined based on the candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter.

[0139] In one embodiment, the parameter processing unit 120 uses an equalizer. The equalizer performs compensation parameter search to obtain compensation parameters to improve signal transmission. Specifically, the equalizer includes a candidate low-frequency gain compensation parameter determination unit, a reference voltage determination unit, a candidate high-frequency gain compensation parameter determination unit, and a target gain compensation parameter determination unit.

[0140] Specifically, the candidate low-frequency gain compensation parameter determination unit is used to perform the aforementioned step S210, that is, the candidate low-frequency gain compensation parameter is used to determine the candidate low-frequency gain compensation parameter. The reference voltage determination unit is used to perform the aforementioned step S220, that is, the reference voltage determination unit is used to determine the high-speed signal reference voltage under the candidate low-frequency gain compensation parameter. The candidate high-frequency gain compensation parameter determination unit is used to perform the aforementioned step S230, that is, the candidate high-frequency gain compensation parameter determination unit is used to determine the candidate high-frequency gain compensation parameter that matches the aforementioned candidate low-frequency gain compensation parameter under the aforementioned high-speed signal reference voltage. The target gain compensation parameter determination unit is used to perform the aforementioned step S240, that is, the target gain compensation parameter determination unit is used to determine the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter that matches it based on the aforementioned candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter that matches it.

[0141] By fixing the low-frequency gain compensation parameters first and then searching for the high-frequency gain compensation parameters that match them during the compensation parameter search process, the compensation requirements for the high-frequency components of the high-speed signal can be determined based on the adjustment range of the low-frequency components of the high-speed signal, thereby quickly and accurately compensating for the high-frequency components of the high-speed signal.

[0142] In one embodiment, in the process of determining the candidate low-frequency gain compensation parameter by the candidate low-frequency gain compensation parameter determination unit, within the adjustment range of the low-frequency gain compensation parameter, one low-frequency gain compensation parameter is selected gear by gear in the order from small to large, and determined as the candidate low-frequency gain compensation parameter. Specifically, the adjustment range of the low-frequency gain compensation parameter is determined according to the attenuation of the extension line of the active cable and the value of the low-frequency gain compensation parameter at each gear. Among them, the attenuation of the extension line of the active cable can be determined by selecting the extension line of more sample active cables on the market to test the insertion loss. By determining the adjustment range of the low-frequency gain compensation parameter according to the attenuation of the extension line of the active cable and the value of the low-frequency gain compensation parameter at each gear, the adjustment range of the low-frequency gain compensation parameter can be reduced from all supported low-frequency gain compensation parameter gears to the compensation range that supports the attenuation of the copper wire extension line, further reducing the search time of the candidate low-frequency gain compensation parameter, thereby further shortening the link training time.

[0143] In one embodiment, in the process of the reference voltage determination unit determining the high-speed signal reference voltage under the candidate low-frequency gain compensation parameters, a reference voltage is selected in the adjustment range of the high-speed signal reference voltage in order from large to small, and the number of high-speed signal sampling points of the reference voltage is counted when the minimum value of the high-frequency gain compensation parameter adjustment range is reached, until a reference voltage whose number of high-speed signal sampling points is greater than the first threshold Th1 is found, and it is determined as the high-speed signal reference voltage under the candidate low-frequency gain compensation parameters.

[0144] By traversing all high-speed signal reference voltages, the high-speed signal is sampled using the high-speed signal reference voltage to obtain the number of sampling points, and the compensation parameters are obtained based on the number of sampling points, so that the screened compensation parameters are more complete.

[0145] Specifically, the first threshold Th1 is an empirical value. In actual application, the user may adjust the first threshold Th1 according to specific scenarios or requirements.

[0146] In another embodiment, in the process of configuring the reference voltage determination unit to determine the high-speed signal reference voltage under the candidate low-frequency gain compensation parameters, a reference voltage is selected by binary search within the adjustment range of the high-speed signal reference voltage, and the first high-speed signal is sampled using the selected reference voltage to obtain the aforementioned number of sampling points.

[0147] The reference voltage is selected by binary search to obtain the number of sampling points, and the compensation parameters are obtained based on the number of sampling points. This can shorten the time for obtaining the reference voltage and make the screening of the compensation parameters more efficient.

[0148] Specifically, in the aforementioned two embodiments, the adjustment range of the high-speed signal reference voltage is determined according to the amplitude range of the active cable and the attenuation of the extension line. The amplitude range of the active cable refers to the maximum and minimum voltage or current values ​​of the signal that the active cable can transmit. This range determines the signal strength that the cable can handle, ensuring that the signal will not be distorted due to excessive amplitude during transmission, nor will it be unable to be correctly recognized by the receiving device due to too small amplitude. The attenuation of the extension line can be determined by selecting a large number of sample active cables on the market to test the insertion loss of the extension line. By determining the adjustment range of the high-speed signal reference voltage based on the amplitude range of the active cable and the attenuation of the extension line, the adjustment range of the high-speed signal reference voltage can be reduced from all supported high-speed signal reference voltage ranges to the compensation range that supports the attenuation of the copper wire extension line, further reducing the acquisition time of the high-speed signal reference voltage.

[0149] In one embodiment, the candidate high-frequency gain compensation parameter determination unit selects a high-frequency gain compensation parameter one by one in an ascending order within the adjustment range of the high-frequency gain compensation parameter in the process of determining the candidate high-frequency gain compensation parameter that matches the candidate low-frequency gain compensation parameter under the aforementioned high-speed signal reference voltage, and counts the number of high-speed signal sampling points under each high-frequency gain compensation parameter, and uses the high-frequency gain compensation parameter with the largest number of high-speed signal sampling points as the candidate high-frequency gain compensation parameter that matches the aforementioned candidate low-frequency gain compensation parameter.

[0150] Specifically, the adjustment range of the high-frequency gain compensation parameter is determined based on the candidate low-frequency gain compensation parameter, and the combination of the high-frequency gain compensation parameter and the candidate low-frequency gain compensation parameter supports the offset of the extension line attenuation. Therefore, the adjustment range of the high-frequency gain parameter only needs to cover the gears that can offset the extension line attenuation with the combination of the candidate low-frequency gain compensation parameter, and there is no need to search from the lowest gear to the highest gear of the high-frequency gain. Therefore, the adjustment range of the high-frequency gain parameter is reduced from all supported high-frequency gain parameter gears to the compensation range that supports the copper wire extension line attenuation, which can further reduce the search time of the candidate high-frequency gain compensation parameter.

[0151] In one embodiment, the target gain compensation parameter determination unit performs the following steps in the process of determining the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter matching the candidate high-frequency gain compensation parameter according to the aforementioned candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter matching the candidate high-frequency gain compensation parameter: counting the size count1 of the number of high-speed signal sampling points of the high-speed signal reference voltage when the high-frequency gain compensation parameter adjustment range is the minimum value under the candidate low-frequency gain compensation parameter, and the size count2 of the number of high-speed signal sampling points of the high-speed signal reference voltage under the candidate high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter; determining the first candidate low-frequency gain compensation parameter whose count2-count1 is greater than the second threshold value Th2 as the target low-frequency gain compensation parameter, and determining the candidate high-frequency gain compensation parameter matching the candidate high-frequency gain compensation parameter as the target high-frequency gain compensation parameter; and setting the default value to the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter when count2-count1 is less than or equal to the second threshold value Th2 under all candidate low-frequency gain compensation parameters.

[0152] Specifically, the second threshold Th2 is an empirical value. In actual application, the user can adjust the second threshold Th2 according to specific scenarios or requirements.

[0153] Specifically, the default value is an empirical value that satisfies the extension line attenuation compensation. It is a parameter value that can make most source end / destination end combinations light up normally through system testing, or a parameter value that can compensate for the attenuation of most extension line samples by measuring the insertion loss of the copper wire extension line samples at the source end.

[0154] In summary, through the scheme for active cable parameter equalization provided above, the disclosed embodiment performs link training on the source end and the active cable transmitting end. During the link training process, the module for active cable parameter equalization obtains the target compensation parameter to improve the high-speed signal. Then, the improved high-speed signal with better signal quality is transmitted to the destination end, and the destination end uses the received improved high-speed signal to perform link training with the source end, which can shorten the link training time.

[0155] Furthermore, when searching for compensation parameters using a module for active cable parameter equalization, shutting down high-speed signal transmission can avoid erroneous activation of the compensation parameter algorithm and prevent uncompensated high-speed signals from being transmitted to the receiving end, causing link training failure.

[0156] Furthermore, the need to search for compensation parameters is determined by the change in the high-speed signal flag, which improves the accuracy of monitoring and avoids errors caused by delays in starting the compensation parameter algorithm.

[0157] Furthermore, the compensation parameters include low-frequency gain compensation parameters and high-frequency gain compensation parameters, thereby increasing the compensation range and avoiding the problem that the high-speed signal quality is severely attenuated in long-distance transmission and connection scenarios via extension cables, and only adjusting the high-frequency gain parameters cannot meet communication needs.

[0158] Furthermore, during the compensation parameter search process, the low-frequency gain compensation parameter is first fixed and then the high-frequency gain compensation parameter matching it is searched. Based on the adjustment range of the low-frequency component of the high-speed signal, the compensation requirement of the high-frequency component of the high-speed signal can be determined, thereby quickly and accurately compensating the high-frequency component of the high-speed signal.

[0159] Furthermore, by confirming the adjustment range of the low-frequency gain compensation parameter, the search time for candidate low-frequency gain compensation parameters is reduced, and the link training time is further shortened.

[0160] Furthermore, all reference voltages are traversed in a combined manner, and the high-speed signal is sampled using the reference voltage to obtain the number of sampling points, and the compensation parameters are obtained based on the number of sampling points, so that the screened compensation parameters are more complete and the efficiency of screening the compensation parameters is higher.

[0161] Figure 3 FIG. 2 shows an exemplary structural block diagram of a cable plug 300 according to an embodiment of the present disclosure. Figure 3 As shown, the cable plug 300 can be arranged at the transmitting end of the active cable, and includes a signal receiving module 310, a signal improving module 320 and a signal sending module 330. The signal receiving module 310 is used to receive a first high-speed signal. The signal improving module 320 may include the module 100 for active cable parameter equalization of the embodiment of the disclosure, which is used to improve the first high-speed signal to obtain a second high-speed signal. The signal sending module 330 is used to output a second high-speed signal.

[0162] In one embodiment, the signal receiving module 310 may be a different type of connector such as USB, type-C, HDMI, etc., and is connected to the source end source through a high-speed signal line, and is used to receive the high-speed signal sent by the source end source, and send the received high-speed signal to the signal improvement module 320. It can be understood that the connection can be directly connected to the source end source, and can also be connected to the source end source through one or more extension lines.

[0163] Specifically, the module 100 may include a control unit 110, a parameter processing unit 120, a configuration unit 130, and a monitoring unit 140. The monitoring unit 140 may be connected to the source end source through the signal receiving module 310 and / or the low-speed signal line. In response to detecting that the source end source starts link training on the low-speed signal line 3, and the monitoring unit 140 monitors that the signal receiving module 310 sends a first high-speed signal, the control unit 110 stops the high-speed signal transmission of the sending end, and the parameter processing unit 120 performs link training with the source end source according to the sequence for link training sent by the source end source. The parameter processing unit 120 searches for compensation parameters to obtain target compensation parameters. The configuration unit 130 sets the target compensation parameters obtained by the parameter processing unit 120 to improve the first high-speed signal sent by the signal receiving module 310 to obtain a second high-speed signal and send it to the control unit 110. The signal sending module 330 may be connected to the control unit 110, and the control unit 110 sends the second high-speed signal to the signal sending module 330 for output.

[0164] Specifically, the signal sending module 330 may be a part of the control unit 110 , or may be an output unit connected to the control unit 110 and including a transmission medium such as an optical fiber or a copper wire.

[0165] Figure 4 FIG. 4 is an exemplary flow chart of a method 400 for active cable link training according to an embodiment of the present disclosure. Figure 4 As shown, in step S410, the module 100 for active cable parameter equalization is used to search for compensation parameters, thereby obtaining target compensation parameters.

[0166] Specifically, in the process of obtaining the target compensation parameters, when the monitoring unit 140 monitors the change of the high-speed signal flag, the control unit 110 stops the transmitter from transmitting high-speed signals, and the parameter processing unit 120 performs link training with the source source according to the sequence for link training sent by the source source. The parameter processing unit 120 searches for compensation parameters to obtain the target compensation parameters. In the process of obtaining the target compensation parameters, considering the situation of adding a copper wire extension line between the source and the transmitter, the target low-frequency gain compensation parameters and the target high-frequency gain compensation parameters matching them are obtained respectively.

[0167] After obtaining the target compensation parameters, in step S420, the transmitting end sends the high-speed signal improved according to the target compensation parameters to the receiving end to complete the link training of the active cable. In one embodiment of the present invention, the destination end connected to the receiving end uses the output of the transmitting end to complete the link training together with the source end connected to the transmitting end.

[0168] Specifically, the configuration unit 130 sets the target compensation parameters obtained by the parameter processing unit 120 for improving the high-speed signal. Then, the parameter processing unit 120 stops the compensation parameter search, and the control unit 110 restarts the high-speed signal transmission of the transmitting end, and transmits the improved high-speed signal with better signal quality to the receiving end. Then, the receiving end sends the improved high-speed signal with better signal quality to the destination sink, and the destination sink uses the received improved high-speed signal to perform link training with the source source.

[0169] Specifically, since the target compensation parameter is obtained by taking into account the case of adding a copper extension line between the source end and the sending end, and the high-speed signal is improved by using the target compensation parameter, a high-speed signal with better signal quality is obtained. Therefore, when the destination end sink uses the received high-speed signal with better signal quality to perform link training with the source end source, the high-speed signal attenuation is weak, which can shorten the link training time.

[0170] In one embodiment of the present invention, when the destination end connected to the receiving end uses the output of the transmitting end to complete the link training process together with the source end connected to the transmitting end, the source end of the active cable reads and writes the register on the destination end, and obtains the state of the destination end by reading and writing the register. According to the state of the destination end, link training is established between the source end and the destination end. During the link training, the source end writes to the register on the destination end to indicate the configuration of the link training, and the destination end also writes the results of each link training stage here.

[0171] Specifically, the status of the destination end includes whether the link training is successful, whether the destination end is ready for link training, whether the destination end starts link training, and the like.

[0172] Figure 5 FIG. 5 shows an exemplary structural block diagram of a first active cable 500 according to an embodiment of the present disclosure. Figure 5 As shown, the first active cable 500 includes: an optical cable 510 and a portion of the cable plug 300 of the embodiment of the present disclosure. Specifically, a portion of the cable plug 300 includes a signal improvement module 320 and a signal sending module 330. Among them, the signal improvement module 320 and the signal sending module 330 in the cable plug 300 of the embodiment of the present disclosure are arranged at the transmitting end TX of the first active cable 500, and the signal improvement module 320 is connected to the signal receiving module 310 in the aforementioned cable plug 300, and the signal receiving module 310 is coupled to the source end source. Specifically, one end of the optical cable 510 is connected to a portion of the cable plug 300 of the embodiment of the present disclosure, and the other end is connected to the optical fiber connector, and the optical cable 510 is used to transmit the signal emitted by the transmitting end to the optical fiber connector. The optical fiber connector is used to connect to another optical cable to facilitate wiring.

[0173] It is understandable that the optical fiber connector may include an LC optical fiber connector, an MPO optical fiber connector, etc. Since the attenuation of the optical signal in the optical fiber can be ignored, a wiring system is adopted in which one end of the optical cable 510 is connected to the module 100 and the other end is connected to the optical fiber connector, and the optical fiber connector is connected to another optical cable. The module 100 is used as the input end of the wiring system, and the other optical cable is used as the output end of the wiring system. The delay and attenuation of the signal from the input end of the wiring system to the output end of the wiring system are no different from those of the conventional AOC, and the link training time of the wiring system is not increased, thereby ensuring the stability of the wiring system communication.

[0174] Specifically, the signal improvement module 320 includes the module 100 for active cable parameter equalization according to the embodiment of the present disclosure. Thus, the first active cable 500 includes an optical cable 510 and the module 100 for active cable parameter equalization according to the embodiment of the present disclosure. The module 100 may include a control unit 110, a parameter processing unit 120, a configuration unit 130, and a monitoring unit 140, which performs link training using the method 400 for active cable link training according to the embodiment of the present disclosure.

[0175] Fig. 6A FIG. 2 shows an exemplary structural block diagram of a second active cable according to an embodiment of the present disclosure. Fig. 6A As shown, the second active cable includes a transmitting end module 610 , a cable 620 and a receiving end module 630 .

[0176] Specifically, the transmitting module 610 may be a part of the cable plug 300 of the embodiment of the present disclosure. Part of the cable plug 300 includes a signal improvement module 320 and a signal transmission module 330. The transmitting module 610 is coupled to the source end source through a high-speed signal line and a low-speed signal line, and the receiving module 630 is used to couple the destination end sink. The cable 620 may be connected to the transmitting module 610 and the receiving module 630.

[0177] Specifically, the transmitting end module 610 is disposed at the transmitting end of the second active cable and is connected to the signal receiving module 310 in the aforementioned cable plug 300 , and the signal receiving module 310 is coupled to the source end source.

[0178] Specifically, the signal improvement module 320 includes the module 100 for active cable parameter equalization of the embodiment of the present disclosure. The module 100 includes a control unit 110, a parameter processing unit 120, a configuration unit 130 and a monitoring unit 140. And the parameter processing unit 120 adopts the equalizer of the embodiment of the present disclosure. Thus, the transmitting end module 610 includes the equalizer of the embodiment of the present disclosure, wherein the equalizer is used to compensate the received high-speed signal according to the compensation parameter.

[0179] Specifically, the equalizer includes a candidate low-frequency gain compensation parameter determination unit, a reference voltage determination unit, a candidate high-frequency gain compensation parameter determination unit and a target gain compensation parameter determination unit. The candidate low-frequency gain compensation parameter is used to determine the candidate low-frequency gain compensation parameter. The reference voltage determination unit is used to determine the high-speed signal reference voltage under the candidate low-frequency gain compensation parameter. The candidate high-frequency gain compensation parameter determination unit is used to determine the candidate high-frequency gain compensation parameter that matches the aforementioned candidate low-frequency gain compensation parameter under the aforementioned high-speed signal reference voltage. The target gain compensation parameter determination unit is used to determine the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter that matches the aforementioned candidate low-frequency gain compensation parameter based on the aforementioned candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter that matches the aforementioned candidate low-frequency gain compensation parameter.

[0180] In one embodiment of the present invention, the second active cable is an AOC, and the cable 620 is an optical cable. The transmitting end module 610 converts the received first high-speed electrical signal into an optical signal. The cable 620 is used to transmit the optical signal emitted by the transmitting end module 610 to the receiving end module 630. The receiving end module 630 converts the received optical signal into a second high-speed electrical signal and provides it to the destination.

[0181] Specifically, the transmitting module 610 may be provided with a first photoelectric conversion module for converting the received first high-speed electrical signal into an optical signal. The receiving module 630 may be provided with a second photoelectric conversion module for converting the received optical signal into a second high-speed electrical signal.

[0182] Specifically, after power-on, the transmitting end module 610 monitors the low-speed signal line, and in response to detecting that the source end starts link training on the low-speed signal line and high-speed signal transmission occurs on the high-speed signal line, stops converting the first high-speed electrical signal into an optical signal. The transmitting end module 610 performs link training with the source end, and uses the aforementioned equalizer to search for target parameters during the link training process. And the received first high-speed electrical signal is compensated with the searched target parameters, an optical signal is generated according to the compensated first high-speed electrical signal, and the optical signal is output to the receiving end module 630 through the cable 620. After the receiving end module 630 converts the received optical signal into a second high-speed electrical signal and provides it to the destination end, the source end and the destination end continue to perform link training through the second active cable and complete the link training.

[0183] In another embodiment of the present invention, the second active cable is an ACC, and the cable 620 is a transmission cable. The cable 620 is used to transmit the high-speed electrical signal sent by the transmitting module 610 to the receiving module 630. The receiving module 630 receives the high-speed electrical signal and provides it to the destination.

[0184] Specifically, after power-on, the transmitting end module 610 monitors the low-speed signal line, and in response to detecting that the source end starts link training on the low-speed signal line, and high-speed signal transmission occurs on the high-speed signal line, stops transmitting the high-speed signal, and the transmitting end module 610 performs link training with the source end, and uses the aforementioned equalizer to search for target parameters during the link training process. And the received first high-speed electrical signal is compensated with the searched target parameters, a second high-speed electrical signal is generated according to the compensated first high-speed electrical signal, and the second high-speed electrical signal is output to the receiving end module 630 through the transmission cable 620. After the receiving end module 630 provides the received second high-speed electrical signal to the destination end, the source end and the destination end continue to perform link training through the second active cable, and complete the link training.

[0185] In the above two embodiments, link training is performed on the source end and the transmitting end module 610. During the link training process, the target parameter is searched by the above equalizer to compensate the received first high-speed electrical signal, and the second high-speed electrical signal is generated according to the compensated first high-speed electrical signal. Then, the improved second high-speed electrical signal with better signal quality is transmitted to the destination end, and the destination end uses the received improved second high-speed electrical signal to perform link training with the source end, which can shorten the link training time.

[0186] In the above two embodiments, the sending end module 610 determines that high-speed signal transmission occurs on the high-speed signal line when the high-speed signal flag bit changes. Specifically, the sending end module 610 determines that high-speed signal transmission occurs on the high-speed signal line when the high-speed signal flag bit changes from 1 to 0.

[0187] In the above two embodiments, the target parameter includes a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matched therewith. Specifically, the target low-frequency gain compensation parameter is used to compensate for the low-frequency component of the first high-speed electrical signal received by the transmitting module 610. The target high-frequency gain compensation parameter is used to compensate for the high-frequency component of the first high-speed electrical signal received by the transmitting module 610.

[0188] In the above two embodiments, the sending end module 610 can be directly connected to the source end source.

[0189] Figure 6B FIG. 2 shows an exemplary structural block diagram of a second active cable with a copper extension line added according to an embodiment of the present disclosure. Figure 6B As shown, in the above two embodiments, the transmitter module 610 can be connected to the source end through one or more copper extension lines 640. This will cause serious signal quality degradation, increase the link training time, cause the link training to time out, and thus cause the link training to fail.

[0190] By respectively obtaining the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter that matches it, the compensation range can be increased, thereby solving the problem that in the scenario where a copper wire extension line is added between the source end and the transmitting end module 610, the high-speed signal attenuation is severe and only adjusting the high-frequency gain parameter cannot meet the communication requirements.

[0191] At the same time, after the receiving end module 630 provides the received second high-speed electrical signal to the destination end, the source end and the destination end continue to perform link training using the compensated second high-speed electrical signal and complete the link training. This can shorten the link training time and make up for the problem caused by the above-mentioned scenario of adding copper extension lines.

[0192] In the above two embodiments, the receiving end module 630 can be directly connected to the destination sink, or connected to the destination through other cables such as optical cables.

[0193] The second active cable of the embodiment of the present disclosure searches for target parameters through the equalizer compensation parameter search method 700 for active cables, and compensates the received high-speed electrical signal with the searched target parameters.

[0194] Specifically, the second active cable includes an AOC and an ACC. The AOC and the ACC may be directly connected to the source end or the destination end, or may be connected to the source end through an extension cable and connected to the destination end through other cables such as an optical cable.

[0195] Figure 7 An exemplary flow chart of an equalizer compensation parameter search method 700 for link training of an active cable according to an embodiment of the present disclosure is shown.

[0196] like Figure 7 As shown, in step S710, candidate low-frequency gain compensation parameters are determined.

[0197] In step S720, a reference voltage level k corresponding to the eye diagram amplitude under the candidate low-frequency gain compensation parameter is determined, wherein the number of sampling points obtained by sampling the high-speed signal with the reference voltage level k when the boundary value within the adjustment range of the candidate low-frequency gain compensation parameter and the high-frequency gain parameter is count1, and count1 is greater than the first threshold Th1. Thus, count1 is the number of sampling points at the reference voltage level k corresponding to the eye diagram amplitude when there is no high-frequency gain.

[0198] In step S730, the optimal high-frequency gain compensation parameter is searched within the adjustment range of the high-frequency gain parameter, and the number of sampling points obtained by sampling the high-speed signal with the reference voltage level k when using the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter is recorded as count2.

[0199] In step S740, determine the compensation parameter according to whether count2 - count1 is greater than the second threshold Th2.

[0200] Specifically, the second threshold Th2 is an empirical value.

[0201] Specifically, within the adjustment range of the low - frequency gain compensation parameter, select a low - frequency gain compensation parameter one by one in ascending order, and determine it as the candidate low - frequency gain compensation parameter.

[0202] Specifically, the adjustment range of the low - frequency gain compensation parameter is determined according to the attenuation of the extension cable of the active cable and the value of the low - frequency gain compensation parameter at each gear. The adjustment range of the low - frequency gain compensation parameter is {M1, M2}, M1 < M2, where the selection of M1 satisfies (Q1 - P1) = S1, the selection of M2 satisfies (Q1 - P2) = S2, and where, {P1, P2} is the compensation ability corresponding to {M1, M2}, Q1 is the compensation ability corresponding to the high - frequency maximum compensation gear parameter of the high - frequency gain compensation parameter, and {S1, S2} is the estimated high - frequency attenuation range of the copper wire extension cable connecting the transmitting - end module 610 and the source end in the second active cable.

[0203] Among them, the high - frequency attenuation range of the copper wire extension cable can be determined by testing the insertion loss of the extension cables of a variety of sample active cables on the market. The high - frequency attenuation range {S1, S2} of the copper wire extension cable can be updated according to the actual application situation. For example, when the copper wire extension cable is updated, {S1, S2} is updated.

[0204] When the compensation ability corresponding to the high - frequency maximum compensation gear parameter of the high - frequency gain compensation parameter remains unchanged, such that the selection of M1 satisfies (Q1 - P1) = S1 and the selection of M2 satisfies (Q1 - P2) = S2, the adjustment range of the low - frequency gain compensation parameter can be determined according to the high - frequency attenuation range of the copper wire extension cable and the value of the low - frequency gain compensation parameter at each gear.

[0205] By determining the adjustment range of the low - frequency gain compensation parameter according to the high - frequency attenuation range of the copper wire extension cable and the value of the low - frequency gain compensation parameter at each gear, the adjustment range of the low - frequency gain compensation parameter can be reduced from all supported low - frequency gain compensation parameter gears to the compensation range that supports the attenuation of the copper wire extension cable, further reducing the search time of the candidate low - frequency gain compensation parameter, thereby further shortening the link training time.

[0206] Within the adjustment range of the high-speed signal reference voltage, select a reference voltage, and sample the high-speed signal with the selected reference voltage to obtain the number of sampling points C[k], where k represents the selected reference voltage level. By selecting different reference voltages until the reference voltage level k that makes C[k]>Th1 is found, then record Count1 = C[k].

[0207] Specifically, during the link training process of the second active cable, the source end will send a high-speed signal to the transmitting end module 610. After receiving this high-speed signal, the transmitting end module 610 can use the method of EOM (Eye Opening Monitor) to sample the vertical eye diagram and detect the eye diagram amplitude. The specific process is as follows: The transmitting end module 610 can use the sampling circuit to sample the voltage value of the received high-speed signal. As long as the sampling frequency is higher than the signal rate and not an integer multiple of the signal rate, gradually scan each high-speed signal reference voltage. After a period of sampling, for example, a total of T samplings are performed, and the eye diagram of the high-speed signal sent by the source end can be sampled. When the low-frequency gain parameter is fixed, the amplitude of the eye diagram is relatively stable. If the high-speed signal reference voltage is scanned from high to low, theoretically, the number of reference voltage sampling points falling near the amplitude will be more than that of the previous reference voltage, and the percentage of the number of sampling points of the previous reference voltage in all sampling points should be relatively small. In this way, the high-speed reference voltage can be scanned from high to low. When the number of sampling points reaches a certain threshold (such as Th1), it is considered that this reference voltage is the eye diagram amplitude reference voltage.

[0208] Therefore, when the aforementioned C[k]>Th1 holds, the selected reference voltage is the eye diagram amplitude reference voltage. Count1 is the number of sampling points at the eye diagram amplitude reference voltage when the high-frequency compensation gain is set to 0 (i.e., there is no high-frequency compensation gain).

[0209] Specifically, the adjustment range of the aforementioned high-speed signal reference voltage is {R1, R2}, where R1<R2, and the reference voltage range covers {0mV, TXSwingmax}, and TXSwingmax is the maximum value of the eye diagram amplitude, which is the maximum value of the eye diagram amplitude of the transmitting end module 610 of the active cable specified by the protocol. And when the transmitting end module 610 and the source end are connected to the copper wire extension line, this maximum value of the eye diagram amplitude can be used.

[0210] When the number of sampling points is C[k]>Th1, the reference voltage selected is the eye diagram amplitude reference voltage, and the reference voltage range is covered to {0mV, TXSwingmax}, so that the eye diagram amplitude reference voltage that meets the requirements can be quickly located within this range. Therefore, the adjustment range of the high-speed signal reference voltage is reduced from all supported adjustment ranges to make the reference voltage range cover {0mV, TXSwingmax}, which can reduce the adjustment range of the high-speed signal reference voltage, reduce the reference voltage selection time, and further shorten the search time of the gain parameter.

[0211] In one embodiment, within the aforementioned adjustment range of the high-speed signal reference voltage, the initial reference voltage is set to R2, and the high-speed signal is sampled in a descending order to obtain the number of sampling points.

[0212] By traversing all high-speed signal reference voltages, sampling the high-speed signal using the high-speed signal reference voltage to obtain the number of sampling points, and obtaining the compensation parameters based on the number of sampling points, the screened compensation parameters can be made more complete.

[0213] In another embodiment, within the adjustment range of the high-speed signal reference voltage, a reference voltage is selected by binary selection, and the high-speed signal is sampled by the selected reference voltage to obtain the number of sampling points.

[0214] The reference voltage is selected by binary search to obtain the number of sampling points, and the compensation parameters are obtained based on the number of sampling points. This can shorten the time for obtaining the reference voltage and make the screening of the compensation parameters more efficient.

[0215] Next, in step S730, the optimal high-frequency gain compensation parameter is searched within the adjustment range of the high-frequency gain parameter, and the number of sampling points obtained by sampling the high-speed signal with the reference voltage level k when using the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter is recorded as count2.

[0216] Specifically, the adjustment range of the high-speed signal reference voltage is determined according to the amplitude range of the active cable and the attenuation of the extension line, including:

[0217] Specifically, the adjustment range of the aforementioned high-frequency gain parameter is {L1, L2}, where L1 < L2. The selection of L1 satisfies Q1 - P1 = S1, the selection of L2 satisfies Q2 - P1 = S2, and {Q1, Q2} is the compensation ability corresponding to {L1, L2}, P1 is the low-frequency signal compensation ability corresponding to the low-frequency maximum compensation gear of the high-frequency gain compensation parameter, and {S1, S2} is the high-frequency attenuation range of the copper wire extension cable connecting the transmitting end module and the source end. Among them, the high-frequency attenuation range of the copper wire extension cable can be determined by testing the insertion loss of the extension cables of a variety of commercially available sample active cables. The high-frequency attenuation range {S1, S2} of the copper wire extension cable can be updated according to the actual application situation. For example, when the copper wire extension cable is updated, {S1, S2} is updated.

[0218] Since the overall high-frequency compensation effect of the equalizer is high-frequency compensation gain - low-frequency compensation gain, for signals with larger high-frequency attenuation, the smaller the low-frequency gain gear and the larger the high-frequency gain gear, the better the compensation effect. For signals with smaller high-frequency attenuation, the smaller the low-frequency gain gear and the larger the high-frequency gain gear, the worse the compensation effect. That is, for signals with smaller high-frequency attenuation, the larger the low-frequency gain gear and the smaller the high-frequency gain gear, the better the compensation effect. Thus, when the low-frequency gain gear remains unchanged, that is, when the low-frequency signal compensation ability corresponding to the low-frequency maximum compensation gear of the high-frequency gain compensation parameter remains unchanged, when the high-frequency attenuation range of the copper wire extension cable is S1, at this time, the high-frequency attenuation is small, so that the selection of L1 satisfies Q1 - P1 = S1, Q1 corresponds to a smaller high-frequency gain gear, and the compensation effect is better; when the low-frequency gain gear remains unchanged, that is, when the low-frequency signal compensation ability corresponding to the low-frequency maximum compensation gear of the high-frequency gain compensation parameter remains unchanged, when the high-frequency attenuation range of the copper wire extension cable is S2, at this time, the high-frequency attenuation is large, so that the selection of L2 satisfies Q2 - P1 = S2, Q2 corresponds to a larger high-frequency gain gear, and the compensation effect is better.

[0219] By making the selection of L1 satisfy Q1 - P1 = S1 and the selection of L2 satisfy Q2 - P1 = S2, the adjustment range of the high-frequency gain parameter can be reduced from all supported high-frequency gain parameter gears to the compensation range that supports the attenuation of the copper wire extension cable. By reducing the adjustment range of the high-frequency gain parameter from all supported high-frequency gain parameter gears to the compensation range that supports the attenuation of the copper wire extension cable, the search time for candidate high-frequency gain compensation parameters can be further reduced.

[0220] Figure 8 An exemplary flowchart showing a method for searching equalizer compensation parameters according to an embodiment of the present disclosure is shown.

[0221] As Figure 8As shown, in step S801, the transmitting end module 610 in the second active cable is powered on and initialized. After the transmitting end module 610 in the second active cable is powered on, in step S802, the low-speed signal line is monitored to determine whether the source end starts link training on the low-speed signal line, and the high-speed signal flag bit is monitored to change from 1 to 0 (indicating whether there is a high-speed signal on the high-speed signal line).

[0222] In response to not detecting the source end starting link training on the low-speed signal line, or not monitoring the high-speed signal flag from 1 to 0, in step S802, continue to monitor the low-speed signal line. In response to detecting the source end starting link training on the low-speed signal line, and monitoring the high-speed signal flag from 1 to 0 (representing the high-speed signal line The high-speed signal appears), in step S803, initialize i=0, j=0, k=0, CountMax=0, stop transmitting the high-speed signal, so that the transmitting end module 610 performs link training with the source end, and the receiving end module 630 of the active cable does not perform link training with the Sink end. During the link training process, in step S804, determine that the candidate low-frequency gain compensation parameter is DC_Gain[i], and set the high-frequency gain parameter to 0. Specifically, i is the low-frequency gain gear, j is the high-frequency gain gear, k is the reference voltage gear, and CountMax is the maximum number of sampling points when searching for the high-frequency gain compensation parameter.

[0223] In step S805, select a reference voltage level k. In step S806, use the selected reference voltage to sample the high-speed signal to obtain a sampling point number C[k], where k represents the selected reference voltage level. In step S807, determine whether the number of sampling points is C[k]>Th1. When C[k]>Th1 is true, in step S808, record Count1=C[k]. When C[k]>Th1 is not true, reselect the reference voltage level, for example, by changing the value of k to k++ to reselect the reference voltage level, and return to step S805. Loop through steps S805 to S807 until C[k]>Th1 is identified in step S807. Among them, Count1 is the number of sampling points at the eye diagram amplitude reference voltage when the high-frequency compensation gain is set to 0 (i.e., there is no high-frequency compensation gain).

[0224] In step S809, the high-frequency gain compensation parameter peak[j] is searched within the adjustment range of the high-frequency gain parameter, where j is the high-frequency gain gear. In step S810, the high-speed signal is sampled using the reference voltage gear k to obtain a sampling point number C[k], where k is the reference voltage gear selected above. In step S811, it is determined whether C[k]>CountMax is established, where CountMax is the maximum number of sampling points. When C[k]>CountMax is established, in step S812, the high-frequency gain compensation parameter peak[j] at this time is recorded as the optimal high-speed gain parameter peakB, and the number of sampling points is recorded as CountMax. When C[k]>CountMax is not established, step S812 is skipped and step S813 is executed. In step S813, the high-frequency gain compensation parameter is searched again within the adjustment range of the high-frequency gain parameter, that is, j++. In step S814, it is determined whether the re-searched high-frequency gain compensation parameter peak[j]>L2 is established. When peak[j]>L2 is established, in step S8315, the high-frequency gain compensation parameter at this time is recorded as the optimal high-speed gain parameter, and count2=CountMax is recorded. When peak[j]>L2 is not established, return to step S809 and repeat steps S809 to S814 until C[k]>CountMax or the re-searched high-frequency gain compensation parameter is greater than L2.

[0225] Specifically, by obtaining the best high-speed gain parameter, Count2 is the number of sampling points at the eye diagram amplitude of the best high-speed gain parameter position under the condition of determining the candidate low-frequency gain compensation parameter.

[0226] Specifically, when peak[j]>L2 is established, by recording the high-frequency gain compensation parameter at this time as the optimal high-speed gain parameter and recording count2=CountMax, it is possible to avoid searching for the high-frequency gain compensation parameter when the adjustment range of the high-frequency gain parameter is exceeded, thereby avoiding an infinite loop of the high-frequency gain compensation parameter search process and shortening the time for searching the high-frequency gain parameter.

[0227] In step S816, determine whether count2-count1>Th2 is true. When count2-count1>Th2 is true, in step S817, determine that the aforementioned candidate low-frequency gain compensation parameter DC_Gain[i] and the aforementioned optimal high-frequency gain compensation parameter are the searched target parameters, and the parameter search process ends. When count2-count1>Th2 is not true, in step S818, i++. In step S819, determine whether the candidate low-frequency gain compensation parameter DC_Gain[i]>M2 obtained in the process of re-execution of the search target parameter is true, i is the low-frequency gain gear. When DC_Gain[i]>M2 is not true, in step S804, return to step S804 to continue the search target parameter process, and determine another low-frequency gain compensation parameter DC_Gain[i] as a candidate low-frequency gain compensation parameter by changing the i value, until the obtained candidate low-frequency gain compensation parameter and the optimal high-speed gain parameter make count2-count1>Th2 true. When DC_Gain[i]>M2 is established in step S819, that is, within the adjustment range of all low-frequency compensation parameters and the adjustment range of the high-frequency gain parameters, Count2-Count1 is always not greater than the second threshold Th2, and in step S820, the low-frequency compensation gain parameters and the high-frequency gain parameters are set to default values.

[0228] Further, in step S809, the high-frequency gain parameter is set to peak[j], and in step S814, it is identified whether peak[j] is greater than L2, which represents the search range for the high-frequency gain parameter. The search range can be narrowed to speed up the search. For example, the range of searching the high-frequency gain parameter can be narrowed from the overall search range to the gear that supports the compensation range of the copper wire extension line. After setting a certain low-frequency gain gear, the search range of the high-frequency gain parameter only needs to cover the gear that can compensate for the attenuation of the copper wire extension line in combination with the low-frequency gain gear, and there is no need to search from the lowest gear of the high-frequency gain to the highest gear. For example, a certain low-frequency compensation gear is M1, the compensation capacity of the gear is P1, the search range of the high-frequency compensation gear parameter is {L1, L2}, the corresponding compensation capacity is {Q1, Q2}, the attenuation range of the HDMI2.1 extension line is {S1, S2}, the value range of L1 satisfies Q1-P1=S1, and the value range of L2 satisfies Q2-P1=S2. In step S809, the high frequency gain parameter may be set to L1 without starting the search from peak[0].

[0229] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may think of many changes, modifications, and alternatives without departing from the thought and spirit of the present disclosure. It should be understood that in the process of practicing the present disclosure, various alternatives to the embodiments of the present disclosure described herein may be adopted. The attached claims are intended to define the scope of protection of the present disclosure, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An equalizer for obtaining compensation parameters to improve signal transmission, characterized in that: include: a candidate low-frequency gain compensation parameter determination unit, configured to determine a candidate low-frequency gain compensation parameter; A reference voltage determination unit, used to determine a high-speed signal reference voltage under the candidate low-frequency gain compensation parameter; a candidate high frequency gain compensation parameter determination unit, configured to determine a candidate high frequency gain compensation parameter that matches the candidate low frequency gain compensation parameter under the high speed signal reference voltage, and The target gain compensation parameter determining unit is used to determine a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter.

2. The equalizer according to claim 1, characterized in that The candidate low-frequency gain compensation parameter determination unit is configured as follows: Within the adjustment range of the low-frequency gain compensation parameter, one low-frequency gain compensation parameter is selected step by step in an ascending order to be determined as the candidate low-frequency gain compensation parameter.

3. The equalizer according to claim 1, characterized in that The reference voltage determination unit is configured as follows: Within the adjustment range of the high-speed signal reference voltage, a reference voltage is selected in descending order, and the number of high-speed signal sampling points of the reference voltage is counted when the minimum value of the high-frequency gain compensation parameter adjustment range is reached, until a reference voltage whose number of high-speed signal sampling points is greater than a first threshold value Th1 is found, and it is determined as the high-speed signal reference voltage under the candidate low-frequency gain compensation parameter.

4. The equalizer according to claim 1, characterized in that The candidate high frequency gain compensation parameter determination unit is configured as follows: A high-frequency gain compensation parameter is selected one by one in order from small to large, and the number of high-speed signal sampling points under each high-frequency gain compensation parameter is counted, and the high-frequency gain compensation parameter with the largest number of high-speed signal sampling points is used as a candidate high-frequency gain compensation parameter that matches the candidate low-frequency gain compensation parameter.

5. The equalizer according to claim 1, characterized in that The target gain compensation parameter determination unit is configured as follows: Counting the number of high-speed signal sampling points of the high-speed signal reference voltage when the high-frequency gain compensation parameter adjustment range is the minimum value under the candidate low-frequency gain compensation parameter, count1, and the number of high-speed signal sampling points of the high-speed signal reference voltage under the matching candidate high-frequency gain compensation parameter, count2; Determine the first candidate low-frequency gain compensation parameter whose count2-count1 is greater than the second threshold Th2 as the target low-frequency gain compensation parameter, and determine the candidate high-frequency gain compensation parameter matched thereto as the target high-frequency gain compensation parameter; as well as When count2-count1 is less than or equal to the second threshold Th2 under all candidate low-frequency gain compensation parameters, the default values ​​are set as the target low-frequency gain compensation parameter and the target high-frequency gain compensation parameter.

6. A method for searching compensation parameters, characterized in that: include: determining candidate low frequency gain compensation parameters; Determining a high-speed signal reference voltage under the candidate low-frequency gain compensation parameters; determining a candidate high frequency gain compensation parameter that matches the candidate low frequency gain compensation parameter at the high speed signal reference voltage, and According to the candidate low-frequency gain compensation parameter and the candidate high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter, a target low-frequency gain compensation parameter and a target high-frequency gain compensation parameter matching the candidate low-frequency gain compensation parameter are determined.

7. A method for searching equalizer compensation parameters for active cables, characterized in that: The active cable comprises a transmitting end module, a receiving end module and a cable; The sending end module is used to couple with the source end through high-speed signal lines and low-speed signal lines; The cable is used to transmit the first high-speed signal sent by the sending end module to the receiving end module; The receiving end module is used to couple with the destination end, and receive the second high-speed electrical signal and provide it to the destination end; The sending end module includes the equalizer, and the equalizer is used to compensate the first high-speed signal according to the compensation parameter; The method includes: In response to the power-on of the sending end module, monitor the low-speed signal line; In response to detecting that the source end starts link training on the low-speed signal line and a high-speed signal transmission appears on the high-speed signal line, search for target parameters; Wherein the search for target parameters includes: Determine candidate low-frequency gain compensation parameters; Determine the reference voltage level k corresponding to the eye diagram amplitude under the candidate low-frequency gain compensation parameter, wherein when using the boundary value within the adjustment range of the candidate low-frequency gain compensation parameter and the high-frequency gain parameter, the number of sampling points obtained by sampling the first high-speed signal with the reference voltage level k is count1, and count1 is greater than the first threshold; Search for the optimal high-frequency gain compensation parameter within the adjustment range of the high-frequency gain parameter, and record that when using the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter, the number of sampling points obtained by sampling the first high-speed signal with the reference voltage level k is count2; Determine the compensation parameter according to whether count2 - count1 is greater than the second threshold.

8. The method for searching the equalizer compensation parameter for an active cable according to claim 7, wherein: If count2 - count1 is greater than the second threshold Th2, determine the candidate low-frequency gain compensation parameter and the optimal high-frequency gain compensation parameter as the searched target parameters; If count2 - count1 is not greater than the second threshold Th2, then perform the process of searching for target parameters again, wherein, in the process of performing the process of searching for target parameters again, determine another low-frequency gain compensation parameter as the candidate low-frequency gain compensation parameter.

9. The equalizer compensation parameter search method for active cables according to claim 8, characterized in that: The determination of another low-frequency gain compensation parameter as the candidate low-frequency gain compensation parameter includes: Within the adjustment range of the low-frequency gain compensation parameter, select a low-frequency gain compensation parameter one by one in ascending order and determine it as the candidate low-frequency gain compensation parameter.

10. The equalizer compensation parameter search method for active cables according to claim 9, characterized in that: The adjustment range of the low-frequency gain compensation parameter is {M1, M2}, M1 < M2, wherein the selection of M1 satisfies (Q1 - P1) = S1, the selection of M2 satisfies (Q1 - P2) = S2, and wherein, {P1, P2} is the compensation ability corresponding to {M1, M2}, Q1 is the compensation ability corresponding to the high-frequency maximum compensation level parameter of the high-frequency gain compensation parameter, and {S1, S2} is the estimated high-frequency attenuation range of the copper wire extension connecting the sending end module and the source end.

11. The equalizer compensation parameter search method for active cables according to any one of claims 7 to 10, characterized in that: The determination of the reference voltage level k corresponding to the eye diagram amplitude under the candidate low-frequency gain compensation parameter includes: Within the adjustment range of the high-speed signal reference voltage, select a reference voltage, sample the first high-speed signal with the selected reference voltage, and obtain the number of sampling points as C[k], where k represents the selected reference voltage level; by selecting different reference voltages until a reference voltage level k is found such that C[k]>Th1, then record Count1 = C[k], where Th1 is the first threshold.

12. The equalizer compensation parameter search method for active cables according to claim 11, characterized in that: The search range of the high-speed compensation parameter levels is {L1, L2}, L1 < L2, where the selection of L1 satisfies Q1 - P1 = S1, the selection of L2 satisfies Q2 - P1 = S2, and where {Q1, Q2} is the compensation ability corresponding to {L1, L2}, P1 is the low-frequency signal compensation ability corresponding to the low-frequency maximum compensation level of the high-frequency gain compensation parameter, and {S1, S2} is the estimated high-frequency attenuation range of the copper wire extension connecting the transmitter module and the source end.

13. The equalizer compensation parameter search method for active cables according to claim 12, characterized in that: The adjustment range of the high-speed signal reference voltage is {R1, R2}, R1 < R2, where the adjustment range of the high-speed signal reference voltage covers {0mV, TXSwingmax}, and TXSwingmax is the maximum value of the eye diagram amplitude.

14. The equalizer compensation parameter search method for active cables according to claim 8, characterized in that: Within the adjustment range of all low-frequency compensation parameters and the search range of high-speed compensation parameter levels, if Count2 - Count1 is always not greater than the second threshold Th2, then set the low-frequency compensation gain parameter and the high-frequency gain parameter to the default values.

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