Signal compensation method and signal intermediate device thereof

Abstract

The present invention provides a signal compensation method, firstly, a multimedia information source device and a signal intermediate device are connected by a first transmission line. Then, the signal intermediate device and the multimedia information display device are connected by a second transmission line. Then, according to the signal transmission protocol, the signal intermediate device receives link training signals from the multimedia information source device and the multimedia information display device via the first transmission line and the second transmission line respectively. Finally, the signal intermediate device adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the electrical characteristics of the link training signal.

Description

[Technical field]

[0001] The present invention relates to a signal compensation technology, and more particularly to a signal compensation method and a signal intermediate device for compensating for signal attenuation caused by transmission through a transmission line. [Background technology]

[0002] In recent years, multimedia audio and video technology has developed rapidly. For example, the high-definition multimedia interface (HDMI) or digital visual interface (DVI) with high-speed data transmission capability, or the display port (DP) transmission interface, because it transmits uncompressed audio signals and high-resolution video signals through the same cable, there is no need to convert analog signals into digital signals (A / D) or digital signals into analog signals (D / A), so it can achieve the goal of distortion-free output.

[0003] Among them, USB, HDMI and DisplayPort have progressed to the stage of high-speed transmission. For example, according to the DisplayPort 1.4 standard, the cable supports four channels in each display output, and the data transmission rate of each channel can reach 8.1Gbps. Therefore, four channels can simultaneously transmit high-resolution audio and video signals, and the total bandwidth can reach 32.4Gbps. However, in the field of high-speed transmission technology, the higher the frequency of data, the more susceptible it is to the impedance of the data transmission cable and attenuation during the transmission process.

[0004] See also Figure 1 As shown, it is a schematic diagram of the signal transmission system architecture of the prior art. This system 1 has a signal switching device 10, which has multiple signal input interfaces 100. Each signal input interface 100 can be connected to a corresponding signal source 11, such as a computer, to receive the multimedia signal output by the signal source 11. Among them, the signal input interface 100 is electrically connected to the signal conversion device (dongle) 13 and the signal source 11 through a transmission line 12. The transmission line 12 generally uses a twisted pair, such as Cat.5, etc. The signal conversion device 13 has an interface 130 at one end connected to the transmission line 12, and an image interface 131 at the other end, such as RGB, HDMI, DVI, DisplayPort, etc., and a control signal interface 132 to connect to the signal source 11. The signal switching system 1 further has a plurality of output interfaces 101 for electrically connecting to a remote signal control device (console) 14 via a transmission line 12. The signal control device 14 is electrically connected to a display 15 and an input device 16, such as a keyboard, a mouse, etc.

[0005] When the transmission line 12 transmits a signal, its length will affect the quality of the transmitted signal, especially for high-frequency signals, which are more likely to have attenuation problems due to long-distance transmission. Therefore, in the architecture of the prior art, a test signal is usually loaded on the side of the signal conversion device 13 and transmitted to the signal control device 14. In this architecture, the signal conversion device 13 can be used as a transmitter of the test signal, and the signal control device 14 can be used as a receiver of the test signal. When the signal control device 14 receives the test signal, it will compensate the multimedia signal according to the attenuation state of the test signal. [Summary of the invention]

[0006] The present invention provides a signal compensation method and a signal intermediate device thereof, wherein during the signal transmission process in accordance with the transmission protocol, a link training signal (link training signal) from a multimedia information source device (source) and / or a multimedia information display device (sink), such as a training check signal or a training result signal (training result), is captured. The link training signal has specific stable characteristics, such as a signal of frequency or voltage, current, etc., as a reference, and the change of its continuous AC signal is detected to determine the degree of signal attenuation, thereby automatically adjusting the compensation parameters for compensating the multimedia signal. Through the present invention, the limitation of the prior art that the line length can only be detected and the attenuation compensation can be compensated under the architecture of a transmitter and a receiver can be broken.

[0007] The present invention provides a signal compensation method and a signal intermediate device thereof, which utilizes a bidirectional transmission link training mechanism of an auxiliary transmission channel (AUX Channel) to capture a differential signal output by a transmitting end or a receiving end and detect its electrical characteristics after transmission, thereby achieving the effect of line length attenuation judgment and signal compensation.

[0008] In one embodiment, the present invention provides a signal compensation method, comprising the following steps. First, a multimedia information source device and a signal intermediate device are connected by a first transmission line. Then, the signal intermediate device and the multimedia information display device are connected by a second transmission line. Then, according to the signal transmission protocol, the signal intermediate device receives link training signals from the multimedia information source device and the multimedia information display device via the first transmission line and the second transmission line respectively. Finally, the signal intermediate device adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the electrical characteristics of the link training signal.

[0009] In one embodiment, adjusting the multimedia signal according to the electrical characteristics of the link training signal also includes the following steps: first, extracting the differential signal in the link training signal, then generating a single-ended signal according to the differential signal, and then generating a DC voltage level according to the single-ended signal. Finally, adjusting the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the DC voltage level.

[0010] In one embodiment, the present invention provides a signal intermediate device, which is electrically connected to a multimedia information source device via a first transmission line and is electrically connected to a multimedia information display device via a second transmission line. The signal intermediate device also includes multiple first transmission interfaces, at least one second transmission interface, a switching module, and a signal processor. Each first transmission interface is electrically connected to a multimedia information source device via a first transmission line. Each second transmission interface is electrically connected to a multimedia information display device via a second transmission line. The switching module is electrically connected to multiple first transmission interfaces and at least one second transmission interface, and the switching module is used to switch and select one of the first transmission interfaces to be electrically connected to one of the second transmission interfaces. The signal processor captures link training signals from the multimedia information source device and the multimedia information display device according to a signal transmission protocol, and the signal processor adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the electrical characteristics of the link training signal.

[0011] In one embodiment, the signal processor includes a signal capture unit, a signal conversion unit and a signal processing unit, wherein the signal capture unit captures the differential signal in the link training signal by impedance isolation and converts it into a single-ended signal, the signal conversion unit generates a DC level signal according to the single-ended signal, and the signal processing unit adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the DC voltage level.

[0012] In one embodiment, the present invention further provides a signal intermediate device, which is applicable to a multimedia information source device and a multimedia information display device. The signal intermediate device is directly electrically connected to the multimedia information source device via a first transmission line, and the signal intermediate device is directly electrically connected to the multimedia information display device via a second transmission line. The signal intermediate device includes a signal processor, which receives a training check signal and a multimedia signal from the multimedia information source device via the first transmission line, and transmits the received training check signal and multimedia signal to the multimedia information display device via the second transmission line. Furthermore, the signal processor adjusts the multimedia signal according to the electrical characteristics of the training check signal and transmits it to the multimedia information display device via the second transmission line, so that the multimedia information display device can display the multimedia signal normally.

[0013] In another embodiment, the signal processor further receives a training result signal sent back from the multimedia information display device in response to the training verification signal via a second transmission line, adjusts the received multimedia signal according to the electrical characteristics of the training result signal, and further transmits the adjusted multimedia signal to the multimedia information display device via the second transmission line, so that the multimedia information display device can display the multimedia signal normally.

[0014] The specific technology adopted by the present invention will be further described through the following embodiments and attached drawings.

Brief Description of the Drawings

[0015] Figure 1 A schematic diagram of the closed signal transmission system architecture in the prior art.

[0016] Figure 2 FIG. 4 is a schematic diagram of an embodiment of the signal intermediate device of the present invention.

[0017] Figure 3A and 3B FIG. 4 is a flow chart of a signal compensation method according to an embodiment of the present invention.

[0018] Figure 4 FIG. 4 is a diagram showing the relationship between the voltage and time of the signal output by the signal processor of the present invention.

[0019] Figure 5 It is a schematic diagram of the first embodiment of the intermediate device of the present invention.

[0020] Description of main component symbols:

[0021] 2, 2b-transmission system; 20-signal intermediate device; 20a-intermediate device; 200-first transmission interface; 201-second transmission interface; 202-switching module; 202a-first switch; 202b-second switch; 21, 21a-multimedia information display device; 22-signal processor; 22-signal processor; 220-signal acquisition unit; 221-signal conversion unit; 222-signal processing unit; 223-multimedia signal processing unit; 2230-adjustment unit; 3-multimedia information source device 9a~9e-transmission line; 90-multimedia information transmission channel; 91-auxiliary transmission channel; 900-single-ended signal; 910-DC voltage level; 912-single-ended signal; 913-DC voltage level; 4-signal compensation method; 40~43, 430~433-process. [Specific implementation method]

[0022] Various exemplary embodiments will be more fully described below with reference to the accompanying drawings, some of which are shown in the accompanying drawings. However, the concepts of the present invention may be embodied in many different forms and should not be construed as being limited to the exemplary embodiments described herein. Specifically, these exemplary embodiments are provided so that the present invention will be detailed and complete, and will fully convey the scope of the concepts of the present invention to those skilled in the art. Similar numbers always indicate similar elements. The following will illustrate a signal compensation method and a signal relay device thereof with a variety of embodiments in conjunction with drawings, however, the following embodiments are not intended to limit the present invention.

[0023] See also Figure 2 As shown, the figure is a schematic diagram of an embodiment of the signal intermediate device of the present invention. Figure 2 The signal transmission system 2 shown has a signal intermediate device 20, which in this embodiment is a KVM switch or a matrix array switch. The signal intermediate device 20 has a plurality of first transmission interfaces 200 and at least one second transmission interface 201, wherein the first transmission interface 200 is electrically connected to the multimedia information source device 3 via a transmission line 9a, and the second transmission interface 201 is electrically connected to the multimedia information display device 21 via a transmission line 9b. The multimedia information source device 3 can be a player, such as a DVD player, a blue-ray DVD player, or a computer, etc., but the present invention is not limited thereto. The multimedia information display device 21, for example, is a television, a television wall, or a display for a computer, etc., but the present invention is not limited thereto.

[0024] The first transmission interface 200 and the second transmission interface 201 can be interfaces of DVI, HDMI or DisplayPort. In the present embodiment, they are interfaces of DisplayPort. The transmission lines 9a and 9b can be wires for transmitting multimedia audio and video signals, such as DisplayPort signal lines, HDMI signal lines, DVI signal lines, etc., or can be twisted pairs, such as Category 5 twisted pairs (Category 5), Category 6 or Category 7 twisted pairs, etc., but the present invention is not limited thereto. In the present embodiment, the transmission lines 9a and 9b are DisplayPort transmission lines for transmitting DisplayPort signals of the DisplayPort transmission protocol. The output signal output by the multimedia information source device 3 is transmitted to the signal intermediate device 20 via the transmission line 9a, and the signal intermediate device 20 then transmits the output signal to the multimedia information display device 21 via the transmission line 9b. In one embodiment, the output signal includes a multimedia signal related to the multimedia information, an auxiliary signal related to the control information, and a hot plug detection signal related to hot plug detection. The multimedia signal and the auxiliary signal are differential signals. Because the present embodiment is described with the aid of the DisplayPort video and audio interface, the DisplayPort output signals mentioned below all comply with the specification of the DisplayPort video and audio transmission protocol, but the present invention is not limited thereto.

[0025] Back to Figure 2 As shown, the channel established by the signal intermediate device 20 and the multimedia information source device 3 or the multimedia information display device 21 on the transmission line 9a or 9b has a multimedia information transmission channel 90 and an auxiliary transmission channel 91, wherein the transmission channel 90 is used to transmit multiple pairs of audio and video differential signals ML_Lane_0 to ML_Lane_3 in the DisplayPort signal, and the auxiliary transmission channel 91 is a bidirectional half-duplex channel, which is used to transmit the auxiliary signals (AUX_CH_p, AUX_CH_n) of the differential nature in the DisplayPort signal. The auxiliary signals of DisplayPort are used for management and control signals, such as VESA EDID, MCCS and DisplayPort standards. It should be noted that the signal of the DisplayPort interface also includes hot plug signal (HPD), ground and power pins, which are well known to those skilled in the art and will not be described in detail here. In addition, it should be noted that the transmission wires constituting the multimedia information transmission channel and the auxiliary transmission channel, such as multiple pairs of twisted-pair wires, have the same conductor characteristics, such as material, transmission attenuation characteristics, or impedance.

[0026] In this embodiment, the signal intermediate device 20 also includes a switching module 202 and a signal processor 22. The switching module 202 is electrically connected to a plurality of first transmission interfaces 200 and at least one second transmission interface 201. The switching module 202 can switch and select one of the first transmission interfaces 200 to be electrically connected to one of the second transmission interfaces 201 according to a control selection signal, so that the multimedia information source device 3 connected to the selected first transmission interface 200 can output the output signal to the multimedia information display device 21 electrically connected to the selected second transmission interface 201 to display and output the audio and video information. In this embodiment, the switching module 202 also has a plurality of first switches 202a and a second switch 202b, which are electrically connected to the signal processor 22 respectively to receive the control signal of the signal processor 22 to select the switch. Each first switch 202a is electrically connected to a plurality of multimedia information source devices 3, and a plurality of first switches 202a are electrically connected to the second switches 202b. The signal processor 22 is coupled to the second transmission interface 201 to compensate the multimedia signal output to the second transmission interface 201. It should be noted that the switch module 202 is not limited to the above-mentioned manner. For example, in another embodiment, the switch module 202 can also be a cross point switch.

[0027] In the transmission protocol of DisplayPort, multimedia signals and auxiliary signals are both high-speed differential signals. When the signals are transmitted through the transmission line, their quality will depend on the length of the transmission line. The longer the transmission line is, the greater the attenuation of the audio and video quality will be. Once the attenuation reaches a certain level, the multimedia information display device 21 cannot smoothly output the audio and video information. In order to solve the problem of signal attenuation without adding an additional component to generate a test signal to the multimedia information source device, in this embodiment, a link training signal with fixed characteristics in the DisplayPort transmission protocol, such as a bidirectional communication characteristic of frequency and voltage, is used, such as a training check signal sent by the multimedia information source device, and / or a training result signal sent by the multimedia information display device 21, to detect signal attenuation, so as to perform signal compensation on the multimedia signal, and maintain the output signal output by the multimedia information source device 3 can be displayed on the multimedia information display device 21.

[0028] In one embodiment, see Figure 3A and 3B As shown in FIG. 1 , the figure is a schematic flow chart of an embodiment of the signal compensation method of the present invention. The flow chart of this embodiment is based on Figure 2The structure shown is used for explanation. First, in step 40, channels are established respectively on the transmission line 9a between the signal intermediate device 20 and the multimedia information display device 21 and the transmission line 9b between the signal intermediate device 20 and the multimedia information source device 3. The channels include a multimedia information transmission channel 90 and an auxiliary transmission channel 91. Then, step 41 is performed. According to the signal transmission protocol, the signal intermediate device 20 starts to transmit a link training signal to enable the multimedia information source device 3 and the multimedia information display device 21 to handshake. The link training signal includes a training check signal sent by the multimedia information source device 3 and a training result signal sent by the multimedia information display device 21 in response to the above-mentioned training check signal for handshaking. The detailed handshaking process is based on the transmission protocol and is not repeated here. The signal intermediate device 20 sends the training check signal received from the multimedia information source device 3 to the multimedia information display device 21 via the auxiliary transmission channel. In one embodiment of step 41, after the multimedia information source device 3 is activated, the multimedia information source device 3 transmits the output signal that complies with the DisplayPort transmission protocol to the signal intermediate device 20 via the transmission line 9a. After receiving the signal, the signal intermediate device 20 transmits the output signal output by the selected multimedia information source device 3 to the multimedia information display device 21 coupled to the selected transmission interface 201 according to the transmission interface 201 selected by the switching module 202.

[0029] Once the multimedia information source device 3 is connected to the multimedia information display device 21, the multimedia information source device 3 outputs an output signal that complies with the DisplayPort transmission protocol to the signal intermediate device 20 through the output interface 200 of the connected audio and video signal. The multimedia signal in the output signal is transmitted to the signal intermediate device 20 through the channel 90, and the auxiliary signal in the output signal is transmitted to the signal intermediate device 20 through the channel 91. The signal intermediate device 20 outputs the multimedia signal to the multimedia information display device 21 through the multimedia information transmission channel 90 of the transmission line 9b. As for the auxiliary signal, the auxiliary signal is output to the multimedia information display device 21 through the auxiliary transmission channel 91 of the transmission line 9b. Since the auxiliary signal is a two-way communication signal, the multimedia information source device 3 first reads the EDID information of the multimedia information display device 21 through the signal intermediate device 20, then reads the DPCD information, and then sends a training check signal to the multimedia information display device 21 to perform link training that complies with the transmission protocol.

[0030] Then, in step 42, after the multimedia information display device 21 receives the training check signal, it also generates a training result signal in response to the training check signal according to the signal transmission protocol, and returns the training result signal to the signal intermediate device 20 via the auxiliary transmission channel 91. When the signal intermediate device 20 receives the training result signal returned by the multimedia information display device 21, it will proceed to step 43 to determine compensation information according to the electrical characteristics of the training result signal, and then compensate the multimedia signal output to the multimedia information display device 21 via the multimedia information transmission channel 90 according to the determined compensation information. In this embodiment, the electrical characteristics are implemented by voltage, but the present invention is not limited thereto.

[0031] In step 43, the signal intermediate device 20 determines the compensation information according to the electrical characteristics, and also includes step 430, capturing a differential signal returned by the multimedia information display device. Since the auxiliary signal is a differential signal, and the signal type in the auxiliary channel is not limited to link training, in this embodiment, the signal processor 22 uses a monitoring method to capture the signal for judgment. There are many ways to judge. For example, in one embodiment, the signal processor 22 determines whether it is a training result signal according to the format of the returned differential signal monitored, such as header data, according to the protocol provisions of DisplayPort. In one embodiment, the signal processor 22 can wait for a specific time difference after receiving the training verification signal to capture the returned training result signal. In another embodiment, the signal processor 22 can determine whether it is a training result signal based on the voltage of the captured returned differential signal. For example, in one embodiment, the signal processor 22 determines whether the returned differential signal is a training result signal according to a voltage difference between a first voltage information of the training result signal specified in the transmission protocol and a second voltage information of the returned differential signal. In another embodiment, the signal processor 22 can determine whether it is a training result signal according to the frequency of the returned differential signal (for example, 1 MHz, but the present invention is not limited thereto). In the embodiment of step 430, the determination is made based on voltage.

[0032] After step 430, step 431 is performed to convert the captured differential signal into a single-ended signal 912. In this step, Figure 2 and Figure 4As shown, the signal capture unit 220 generates a single-ended signal 912 according to the captured differential signal. Then, step 432 is performed, and the signal conversion unit 221 generates a DC voltage level 913 according to the single-ended signal 912. Then, step 433 is performed, and when the differential signal returned is determined to be a training result signal according to the DC voltage level 913, the compensation information is determined according to the DC voltage level 913. Among them, the signal processing unit 222 converts the DC voltage level 913 into a digital signal to perform calculations inside the signal processing unit 222. In one embodiment of step 433, the signal processing unit 222 determines the compensation information using a lookup table. The lookup table contains information about the voltage attenuation and the corresponding compensation value. The lookup table is established by first measuring the electrical characteristic attenuation of the transmission line with respect to different length segments, and then establishing the relationship between the electrical characteristic attenuation and the different length segments. Finally, according to the different attenuations, the relationship between the attenuation and the pre-compensation is established to form a lookup table. In step 433, since the voltage value of the training result signal transmitted back from the multimedia information display device 21 has a certain standard according to the communication protocol of the DisplayPort image signal, the DC voltage level 913 is compared with the standard voltage value to determine whether it is a training result signal. If it is a training result signal, the compensation information is determined according to the corresponding DC voltage level, and the multimedia signal output to the multimedia information transmission channel 90 is compensated according to the compensation information.

[0033] See also Figure 5 As shown in FIG. 1 , the figure is a schematic diagram of another embodiment of the signal intermediate device of the present invention. The signal intermediate device 20a in the transmission system 2b of the present embodiment is suitable for the multimedia information source device 3 and the multimedia information display device 21a. In the present embodiment, the multimedia information source device can be a DVD player, a blue-ray DVD player or a computer, etc., but the present invention is not limited thereto. The multimedia information display device 21a is a television or a projector, etc., but the present invention is not limited thereto.

[0034] The input interface 200 of the signal intermediate device 20a is directly electrically connected to the multimedia information source device 3 via the first transmission line 9f, and the output interface 201 of the signal intermediate device 20a is directly electrically connected to the multimedia information display device 21a via the second transmission line 9g. The signal intermediate device 20a has a signal processor 22 inside, which is used to receive the training verification signal and multimedia information from the multimedia information source device 3 via the first transmission line 9f from the input interface 200, and transmit the received training verification signal and multimedia information to the multimedia information display device 21a through the output interface 201 via the second transmission line 9g.

[0035] The signal processor 22 has a signal capture unit 220, a signal conversion unit 221, a signal processing unit 222 and a multimedia signal processing unit 223. The multimedia signal processing unit 223 is used to receive multimedia information transmitted from the multimedia information transmission channel 90 in the transmission line 9f, and output it to the multimedia information display device 21a. The signal capture unit 220 captures the training result signal returned from the multimedia information display device 21a in response to the training verification signal from the auxiliary channel 91, and generates compensation information after signal processing by the signal conversion unit 221 and the signal processing unit 222. The adjustment unit 2230 of the multimedia signal processing unit 223 adjusts the received multimedia information according to the compensation information, and further transmits the adjusted multimedia information to the multimedia information display device 21a via the second transmission line 9g, so that the multimedia information display device 21a can display the multimedia information normally. The compensation and adjustment method is as mentioned above. Figure 3A and 3B The process shown will not be described in detail here.

[0036] It should be noted that the aforementioned embodiment detects the signal attenuation from the signal intermediate device 20 or the signal intermediate device 20a to the multimedia information display device 21 or 21a to perform compensation. In another embodiment, the detection of the signal attenuation from the signal intermediate device 20 or 20a to the multimedia information display device 21 or 21a is not limited. For example, according to the spirit of the aforementioned embodiment, it can also be applied to the detection of the signal attenuation from the multimedia information source device 3 to the signal intermediate device 20 or 20a, or the combination of the aforementioned detection of the signal attenuation from the signal intermediate device 20 or 20a to the multimedia information display device 21 or 21a and the detection of the signal attenuation from the multimedia information source device 3 to the signal intermediate device 20 or 20a to compensate for the multimedia information. Since the spirit of the present invention is to use the fixed signal characteristics in the audio and video transmission protocol, such as: frequency, voltage signal, so between the signal intermediate device 20 or 20a and the multimedia information source device 3, the training check signal belonging to the link signal can be used to make attenuation judgment.

[0037] like Figure 4 and Figure 5As shown, in one embodiment, through the signal capture unit 220, which is a buffer component in this embodiment, it is used to monitor and capture the differential signal on the auxiliary transmission channel 91 and convert the differential signal into a single-ended signal. Preferably, the signal can be further amplified during the conversion process to facilitate interpretation. In addition to being able to capture the differential signal on the auxiliary transmission channel 91, the buffer component can be further selected to have an impedance isolation effect, for example: a differential amplifier with an impedance characteristic of 100 ohms or capable of matching the transmission line impedance without affecting the signal quality, to capture the training verification signal without affecting the signal quality of the auxiliary transmission channel 91. The signal capture unit 220 in this embodiment has the effects of impedance isolation and effective attenuation amplification, but the present invention is not limited thereto.

[0038] Afterwards, a DC voltage level 910 is generated according to the single-ended signal 900 through the signal conversion unit 221. Finally, the signal processing unit 222 determines whether it is a training verification signal according to the DC voltage level 910. In one embodiment, it can be determined whether it is a training verification signal based on whether the differential signal has a specific frequency, for example: 1MHz, but the present invention is not limited to this. In one embodiment, it can be determined based on the unique header data of the auxiliary signal. In addition, in another embodiment, it can be determined whether it is a training verification signal based on the voltage of the captured differential signal. When it is determined to be a training verification signal, the compensation information can be determined based on the DC voltage level 910 it has, which is as described above and will not be repeated here.

[0039] Through the description of the aforementioned embodiments, according to the spirit of the present invention, the signal attenuation caused by the length of the line from the multimedia information source device to the signal intermediate device and from the multimedia information display device to the signal intermediate device during long-distance transmission can be found, and then the compensation amount for the multimedia signal can be determined according to the attenuation so that the compensated multimedia signal can be normally displayed by the multimedia information display device. Although the aforementioned embodiments are described based on the multimedia transmission protocol of DisplayPort, this spirit can be expanded to other transmission protocols. For example, in high-speed multimedia transmission protocols such as DVI or HDMI, an electrical signal with a fixed period can be found, and its attenuation can be determined in the aforementioned spirit.

[0040] Although the embodiments of the present invention are disclosed as described above, they are not intended to limit the present invention. Any person skilled in the relevant art may make slight changes to the shapes, structures, features, methods and quantities described in the claims of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of patent protection of the present invention shall be determined by the scope of the claims attached to this specification.

Claims

1. A signal compensation method, characterized in that: The following steps are involved: Connecting the multimedia information source device and the signal intermediate device with a first transmission line; Connecting the signal intermediate device and the multimedia information display device with a second transmission line; According to a signal transmission protocol, the signal intermediate device receives link training signals from the multimedia information source device and the multimedia information display device via the first transmission line and the second transmission line respectively; and The signal intermediate device adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the electrical characteristics of the link training signal; The step of adjusting the multimedia signal according to the electrical characteristics of the link training signal further includes the following steps: Extracting a differential signal from the link training signal; generating a single-ended signal according to the differential signal; generating a DC voltage level according to the single-ended signal; as well as The multimedia signal transmitted to the multimedia information display device via the second transmission line is adjusted according to the DC voltage level.

2. The signal compensation method according to claim 1, characterized in that: The link training signal includes a training check signal and a training result signal.

3. The signal compensation method according to claim 2, characterized in that: The signal intermediate device determines whether the differential signal is an AC signal of a specific frequency to determine whether the differential signal is the training result signal.

4. The signal compensation method according to claim 2, characterized in that: The method in which the signal intermediate device determines that the returned differential signal is the training result signal also includes the following steps: The signal intermediate device determines whether the returned differential signal is the training result signal according to a voltage difference between first voltage information about the training result signal specified in the signal transmission protocol and second voltage information of the received differential signal.

5. The signal compensation method according to claim 4, characterized in that: The step of establishing a lookup table is also included, wherein establishing the lookup table further comprises the following steps: Measure the electrical characteristic attenuation of transmission lines at different lengths; Establishing the relationship between the electrical characteristic attenuation and the different length segments; and According to different attenuation amounts, a relationship between the attenuation amount and the pre-compensation is established to form the lookup table.

6. The signal compensation method according to claim 5, characterized in that: The signal intermediate device determines compensation information through the lookup table according to the attenuation information of the training result signal, so as to compensate the multimedia signal output to the second transmission line.

7. A signal intermediate device, electrically connected to a multimedia information source device via a first transmission line and electrically connected to a multimedia information display device via a second transmission line, characterized in that: The signal intermediate device includes: A plurality of first transmission interfaces, each of the first transmission interfaces being electrically connected to the multimedia information source device via the first transmission line; at least one second transmission interface, electrically connected to the multimedia information display device via the second transmission line; a switching module, electrically connected to the plurality of first transmission interfaces and the at least one second transmission interface, the switching module being used to switch and select one of the first transmission interfaces to be electrically connected to one of the second transmission interfaces; as well as A signal processor, which captures link training signals from the multimedia information source device and the multimedia information display device according to a signal transmission protocol, and adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the electrical characteristics of the link training signal; The signal processor includes a signal capture unit, a signal conversion unit and a signal processing unit, wherein the signal capture unit captures the differential signal in the link training signal and converts it into a single-ended signal, the signal conversion unit generates a DC voltage level according to the single-ended signal, and the signal processing unit adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the DC voltage level.

8. The signal intermediate device according to claim 7, characterized in that: The link training signal includes a training check signal and a training result signal.

9. The signal intermediate device according to claim 8, characterized in that: The signal processor determines whether the differential signal is an AC signal of a specific frequency to determine whether the differential signal is the training result signal.

10. The signal intermediate device according to claim 8, characterized in that: The signal processor determines whether the returned differential signal is the training result signal according to the voltage difference between the first voltage information about the training result signal specified in the signal transmission protocol and the second voltage information of the received differential signal.

11. The signal intermediate device according to claim 7, characterized in that: The signal processor stores a lookup table having information on the relationship between signal attenuation and compensation. The signal processor determines compensation information through the lookup table according to the electrical characteristics to compensate the multimedia signal output to the multimedia information display device.

12. A signal intermediate device, suitable for a multimedia information source device and a multimedia information display device, wherein the signal intermediate device is directly electrically connected to the multimedia information source device via a first transmission line, and the signal intermediate device is directly electrically connected to the multimedia information display device via a second transmission line, characterized in that: The signal intermediate device includes: a signal processor, which receives a training verification signal and a multimedia signal from the multimedia information source device via the first transmission line, and transmits the received training verification signal and the adjusted multimedia signal to the multimedia information display device via the second transmission line, so that the multimedia information display device can display the multimedia signal normally, wherein the signal processor includes a signal capture unit, a signal conversion unit and a signal processing unit, wherein the signal capture unit captures the differential signal in the training verification signal and converts it into a single-ended signal, the signal conversion unit generates a DC voltage level according to the single-ended signal, and the signal processing unit adjusts the multimedia signal transmitted to the multimedia information display device via the second transmission line according to the DC voltage level.

13. The signal intermediate device according to claim 12, characterized in that: The signal processor further receives a training result signal sent back from the multimedia information display device in response to the training verification signal via the second transmission line, adjusts the received multimedia signal according to the electrical characteristics of the training result signal, and further transmits the adjusted multimedia signal to the multimedia information display device via the second transmission line, so that the multimedia information display device can display the multimedia signal normally.

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