Ethernet device and Ethernet cable diagnosis method

Abstract

The invention discloses an Ethernet device and an Ethernet cable diagnosis method. The Ethernet device comprises a connection test pulse generator circuit, a mixing circuit, a transmission circuit, a receiving circuit and a post-processing circuit. The connection test pulse generator circuit is used for generating a connection test pulse signal meeting the IEEE 802.3 standard. The transmission circuit is used for transmitting the connection test pulse signal to an Ethernet cable through the hybrid circuit. The receiving circuit is used for receiving a receiving signal from the Ethernet cable in a period of time when the connection test pulse signal is transmitted through the hybrid circuit. The post-processing circuit is configured to perform a cable diagnosis of the Ethernet cable according to the received signal.

Description

Technical Field

[0001] The present invention relates to cable diagnosis design, and more particularly to an Ethernet device that utilizes a waveform that complies with the IEEE802.3 standard to perform cable diagnosis and a related Ethernet cable diagnosis method. Background Art

[0002] During the construction of Ethernet networks, link failures may occur due to a variety of reasons. For example, link failures may be caused by unplugging the Ethernet cable or by a damaged Ethernet cable (open or short circuit). Due to the complexity of large Ethernet network topologies, troubleshooting becomes more difficult. In this case, cable diagnostic algorithms become the best solution for Ethernet network troubleshooting. Traditional cable diagnostic algorithms may require the transmitter to send some specific waveforms (e.g., multiple step waves or pseudo random signals) that do not comply with IEEE 802.3 Auto-Negotiation (AN) and may cause some inter-operability test problems. Therefore, an innovative Ethernet cable diagnostic design that does not affect the IEEE 802.3 Ethernet system is needed. Summary of the invention

[0003] One of the objectives of the present invention is to provide an Ethernet device that uses a waveform that complies with the IEEE 802.3 standard to perform cable diagnostics and a related Ethernet cable diagnostic method.

[0004] In one embodiment of the present invention, an Ethernet device is disclosed. The Ethernet device includes a connection test pulse generator circuit, a hybrid circuit, a transmission circuit, a receiving circuit, and a post-processing circuit. The connection test pulse generator circuit is used to generate a connection test pulse signal that complies with the IEEE 802.3 standard. The transmission circuit is used to transmit the connection test pulse signal to an Ethernet cable through the hybrid circuit. The receiving circuit is used to receive a reception signal from the Ethernet cable during a period in which the connection test pulse signal is transmitted through the hybrid circuit. The post-processing circuit is used to perform cable diagnosis of the Ethernet cable according to the reception signal.

[0005] In one embodiment of the present invention, an Ethernet cable diagnostic method is disclosed. The Ethernet cable diagnostic method includes: generating a connection test pulse signal that complies with the IEEE 802.3 standard; transmitting the connection test pulse signal to an Ethernet cable through a hybrid circuit; receiving a reception signal from the Ethernet cable during a period in which the connection test pulse signal is transmitted through the hybrid circuit; and performing cable diagnosis of the Ethernet cable according to the reception signal.

[0006] Since the test signal required by the real-time Ethernet cable diagnosis function proposed by the present invention is an LTP signal that complies with the IEEE802.3 standard, the real-time Ethernet cable diagnosis function can perform cable diagnosis without affecting the normal operation of the IEEE 802.3 Ethernet system. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG. 4 is a schematic diagram of an Ethernet system according to an embodiment of the present invention.

[0008] Figure 2 yes Figure 1 A schematic diagram of an LTP waveform represented by an LTP signal generated by the LTP generator circuit shown.

[0009] Figure 3 FIG. 4 is a waveform diagram of an RX signal when echo cancellation is not enabled / used (HYBRID_EC=off) according to an embodiment of the present invention.

[0010] Figure 4 FIG. 4 is a waveform diagram of an RX signal when echo cancellation is enabled / used (HYBRID_EC=on) according to an embodiment of the present invention.

[0011] Figure 5 FIG. 4 is a flowchart of an operation procedure of recording sampled values ​​of RX signals for subsequent cable status identification according to an embodiment of the present invention.

[0012] Figure 6 4 is a flowchart of an operation procedure of post-processing the sampled values ​​of the recorded RX signal to perform cable status identification according to an embodiment of the present invention.

[0013] Figure 7 FIG. 4 is a flowchart of an operation procedure for recording sample values ​​of an RX signal for subsequent position detection according to an embodiment of the present invention.

[0014] Figure 8 FIG. 4 is a flowchart of an operation procedure of post-processing sample values ​​of a recorded RX signal to perform location detection of a cable problem according to an embodiment of the present invention.

[0015] Fig. 9It is a diagram showing comparison between the waveforms of the RX signal obtained at different positions (lengths) of the cable problem.

[0016]

Explanation of symbols

[0017] 100: Ethernet Network System

[0018] 102: Local Device

[0019] 103: Ethernet cable

[0020] 104: Remote Device

[0021] 106: LTP generator circuit

[0022] 108: TX digital-to-analog converter and driver

[0023] 110: Hybrid Circuit

[0024] 112, 120: RX variable gain amplifier and clipper

[0025] 114: Post-processing circuit

[0026] 116: Hybrid Echo Cancellation Circuit

[0027] 118: Multiplexer

[0028] S502, S504, S506, S508, S510, S512, S514, S516, S518, S602, S604, S606, S608, S610, S612, S702, S704, S706, S708, S710, S712, S714, S716, S718, S802, S804, S806, S808, S810, S812, S814, S816, S818, S820, S822, S824, S826: Steps DETAILED DESCRIPTION

[0029] Certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as the criterion for distinction. The "include" and "including" mentioned throughout the specification and claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the term "coupled" or "coupled" herein includes any direct and indirect electrical connection means. Therefore, if the text describes a first device coupled to a second device, it means that the first device can be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices and connection means.

[0030] Figure 1 1 is a schematic diagram of an Ethernet system according to an embodiment of the present invention. The Ethernet system 100 may include two Ethernet devices, namely a local device 102 and a remote device 104. The local device 102 supports the real-time Ethernet cable diagnostic function proposed by the present invention, which may be run during the AN period or the 10BASE-T idle mode period. In this embodiment, the local device 102 includes a link test pulse (LTP) generator circuit (labeled as “LTP circuit”) 106, a transmit (TX) circuit (including a TX digital-to-analog converter and a driver circuit (labeled as “TX DAC & driver”)) 108, a hybrid circuit 110, a receive (RX) circuit (including a RX variable gain amplifier and a slicer (labeled as “RX VGA & slicer”)) 112, a post-processing circuit 114, a hybrid echo cancellation circuit (labeled as “hybrid echo cancellation”), and a multiplexer (labeled as “MUX”) 118. The remote device 104 includes an RX circuit (including a RX variable gain amplifier and a slicer (labeled as “RX VGA & slicer”)) 120. Please note that Figure 1Only components related to the present invention are shown in the figure. In fact, the local device 102 may include additional components to implement other functions, and / or the remote device 104 may include additional components to implement other functions. In addition, the hybrid echo cancellation circuit 116 and the multiplexer 118 are shown as external components of the hybrid circuit 110. However, in some embodiments of the present invention, the hybrid echo cancellation circuit 116 and the multiplexer 118 may be integrated into the hybrid circuit 110. In short, the present invention does not particularly limit the implementation of the hybrid circuit 110 and the hybrid echo cancellation circuit 116.

[0031] The LTP generator circuit 106 is configured to generate an LTP signal S_LTP (which is a digital signal representing an LTP waveform), wherein the LTP signal S_LTP complies with the IEEE 802.3 standard. Figure 2 yes Figure 1 Schematic diagram of an LTP waveform 202 represented by an LTP signal S_LTP generated by the LTP generator circuit 106 shown. The LTP waveform 202 complies with the LTP template 204 defined by the IEEE 802.3 standard. For example, the LTP waveform 202 should be limited to ±3.1V and the width should not be greater than 42 bit times (BT). In some embodiments of the present invention, the LTP signal S_LTP can be a fast link pulse (FLP) of AN or a normal link pulse (NLP) of 10BASE-T.

[0032] The TX circuit (which includes the TX digital-to-analog converter and the driver 108) receives the LTP signal S_LTP generated by the LTP generator circuit 106 and transmits the corresponding medium dependent interface (hereinafter referred to as "MDI") signal through the Ethernet cable (which is a twisted-pair cable) 103. When the connection between the local device 102 and the remote device 104 is successfully established, the RX circuit (including the RX variable gain amplifier and the clipper 120) of the remote device 104 receives the MDI signal from the Ethernet cable 103 and obtains the LTP signal S_LTP sent by the local device 102. Since the test signal required by the real-time Ethernet cable diagnostic function proposed in the present invention is the LTP signal S_LTP that complies with the IEEE802.3 standard, the real-time Ethernet cable diagnostic function can perform cable diagnosis without affecting the normal operation of the IEEE 802.3 Ethernet system 100.

[0033] The Ethernet cable 103 may be damaged due to an open circuit or a short circuit. The local device 102 may enable the real-time Ethernet cable diagnostic function proposed by the present invention to identify the cable status of the Ethernet cable 103 and / or the location where the Ethernet cable 103 has a cable problem (e.g., an open circuit or a short circuit). When the real-time Ethernet cable diagnostic function proposed by the present invention is enabled, the hybrid circuit 110 operates to achieve simultaneous transmission and reception (i.e., duplex communication) on the same twisted pair of the Ethernet cable 103. Specifically, since the hybrid circuit 110 supports hybrid transmission (i.e., simultaneous transmission and reception), after the LTP signal S_LTP is sent via the Ethernet cable 103, the reflected LTP signal caused by the open circuit, short circuit or impedance mismatch can be received through the loopback feedback transmission of the LTP signal S_LTP. If the local device 102 is a 1000BASE-T device or a 2500BASE-T device, the Ethernet physical layer (PHY) itself already supports hybrid transmission function, so no additional hardware is needed to implement the real-time Ethernet cable diagnosis function proposed by the present invention. In this embodiment, during the period when the LTP signal S_LTP is transmitted through the hybrid circuit 110, the RX circuit of the local device 102 (which includes the RX variable gain amplifier and the clipper 112) is used to receive the RX signal S_RX from the hybrid circuit 110. In this way, by analyzing the signal characteristics of the received signal S_RX, the real-time Ethernet cable diagnosis can be implemented.

[0034] Please note that the real-time Ethernet cable diagnostic function proposed in the present invention can work normally regardless of whether the echo cancellation is enabled / used. Figure 3 FIG. 1 is a waveform diagram of the RX signal S_RX when the echo cancellation is not enabled / used (HYBRID_EC=off) according to an embodiment of the present invention. When the echo cancellation is not enabled / used, the multiplexer 118 controlled by HYBRID_EC=off selects the analog signal S1 as the input of the RX circuit (which includes the RX variable gain amplifier and the clipper 112) of the local device 102. Regarding the case where the cable status is OPEN (i.e., the Ethernet cable 103 is open), as shown in FIG. Figure 3As shown in the sub-figure (A) of FIG. 1 , the RX signal S_RX includes an echo signal 302 caused by the LTP signal S_LTP being transmitted through the hybrid circuit 110, and a positive reflection signal 304 generated by the LTP signal being reflected due to the high impedance of the open circuit. Regarding the case where the cable status is SHORT (i.e., the Ethernet cable 103 is short-circuited), as shown in FIG. Figure 3 As shown in the sub-figure (C) of FIG. 1 , the RX signal S_RX includes an echo signal 302 caused by the LTP signal S_LTP being transmitted through the hybrid circuit 110, and a negative reflection signal 306 generated by the LTP signal being reflected due to the short circuit having a low impedance. Regarding the case where the cable state is LOAD (i.e., the Ethernet cable 103 is a load circuit), as shown in FIG. Figure 3 As shown in sub-figure (B), the RX signal S_RX includes the echo signal 302 caused by the LTP signal S_LTP being transmitted through the hybrid circuit 110. However, due to the impedance matching between the local device 102 and the remote device 104, the RX signal S_RX does not have the reflection signal generated by the reflection of the LTP signal.

[0035] Figure 4 FIG. 1 is a waveform diagram of the RX signal S_RX when the echo cancellation is enabled / used (HYBRID_EC=on) according to an embodiment of the present invention. When the echo cancellation is enabled / used, the multiplexer 118 controlled by HYBRID_EC=on selects the analog signal S2 as the input of the RX circuit (which includes the RX variable gain amplifier and the clipper 112) of the local device 102. Regarding the case where the cable status is OPEN (i.e., the Ethernet cable 103 is open), as shown in FIG. Figure 4 As shown in the sub-figure (A) of FIG. 1 , the RX signal S_RX does not include the echo signal caused by the LTP signal S_LTP being transmitted through the hybrid circuit 110, but includes the positive reflection signal 402 generated by the LTP signal being reflected due to the high impedance of the open circuit. Regarding the case where the cable status is SHORT (i.e., the Ethernet cable 103 is short-circuited), as shown in FIG. Figure 4 As shown in the sub-figure (C) of FIG. 1 , the RX signal S_RX does not include the echo signal caused by the LTP signal S_LTP being transmitted through the hybrid circuit 110, but includes the negative reflection signal 404 generated by the LTP signal being reflected due to the short circuit having a low impedance. Regarding the case where the cable state is LOAD (i.e., the Ethernet cable 103 is a load circuit), as shown in FIG. Figure 4 As shown in sub-figure (B), the RX signal S_RX does not include the echo signal caused by the LTP signal S_LTP being transmitted through the hybrid circuit 110. In addition, due to the impedance matching between the local device 102 and the remote device 104, the RX signal S_RX does not have the reflection signal generated by the LTP signal reflection.

[0036] When the RX signal S_RX has Figure 3 and Figure 4 When any waveform shown is obtained, the real-time Ethernet cable diagnostic function proposed by the present invention can operate normally. The post-processing circuit 114 is used to perform cable diagnosis on the Ethernet cable 103 according to the received signal S_RX. The operation procedure of the real-time Ethernet cable diagnostic function proposed by the present invention can be divided into a recording phase and an analysis phase, wherein the recording phase is used to record the sample value of the RX signal S_RX (which is a digital signal representing the RX waveform with / without echo cancellation), and the analysis phase is used to identify one or both of the cable status and the location (length) of the channel problem. In this embodiment, the total power of the observed RX waveform can indicate the cable status, and the timing of the reflected wave can indicate the location (length) of the channel problem. The following is a detailed description of the further details of the real-time Ethernet cable diagnostic function proposed by the present invention with reference to the accompanying drawings.

[0037] Figure 5 4 is a flowchart of an operation procedure of recording sampled values ​​of the RX signal S_RX for subsequent cable status identification according to an embodiment of the present invention. Figure 5 The steps shown may be performed by the post-processing circuit 114. The steps do not have to be exactly the same as above provided that substantially the same results can be obtained. Figure 5. In step S502, the cable status is unknown. In step S504, the post-processing circuit 114 checks whether the connection between the local device 102 and the remote device 104 has been successfully established. If the connection status indicates that the connection has been successfully established, the post-processing circuit 114 identifies the cable status as LOAD and ends the process. If the connection status indicates that the connection has not been successfully established, the post-processing circuit 114 performs initialization of the recording process (step S506), so that the recording process is started (CDT_en=ENABLE), the hybrid echo cancellation circuit 116 can be enabled / used (enabled / used) or disabled / bypassed (HYBRID_EC=off / on), and the recording index value (recording index) REC_IDX is initialized to a preset value (REC_IDX=0). In step S510, the post-processing circuit 114 checks whether the transmission of the LTP signal S_LTP has started by checking the status of one or more related signals (e.g., signal XMIT_LTP). When the status of the signal XMIT_LTP is true, it means that the transmission of the LTP signal S_LTP has started, and the post-processing circuit 114 starts to record the sampled values ​​CDP_REC[REC_IDX] of the RX signal S_RX output by the RX circuit (including the RX variable gain amplifier and the clipper 112) of the local device 102. These sampled values ​​are the digital values ​​ADC_IN sequentially output by the received signal S_RX. The post-processing circuit 114 will continue to execute the recording process until the recorded index value REC_IDX reaches the maximum value MAX_IDX (steps S512 and S514). When the plurality of sample values ​​CDP_REC[0]-CDP_REC[MAX_IDX-1] have been recorded (ie, the number of recorded sample values ​​is equal to MAX_IDX), the post-processing circuit 114 stops the recording process (CDT_en=DISABLE) and enables subsequent cable status identification post-processing (steps S516 and S518).

[0038] Figure 6 4 is a flowchart of an operation procedure of post-processing the sampled values ​​of the recorded RX signal S_RX to perform cable status identification according to an embodiment of the present invention. Figure 6 The steps shown are performed by the post-processing circuit 114. The steps do not have to be exactly the same as above provided that substantially the same results can be obtained. Figure 6Execute in sequence according to the order shown. In step S602, the accumulated result pwr_sum is initialized to a preset value (pwr_sum = 0). In step S604, the post-processing circuit 114 accumulates multiple sample values CDP_REC[0] to CDP_REC[MAX_IDX - 1] as an estimate of the total power of the observed RX signal S_RX, and updates the accumulated result pwr_sum (pwr_sum = sum(CDP_REC[0:MAX_IDX - 1])). In step S606, the post-processing circuit 114 compares the accumulated result pwr_sum with a predetermined threshold thrs_pwr_total_open. When the accumulated result pwr_sum is greater than the predetermined threshold thrs_pwr_total_open, the post-processing circuit 114 identifies the cable status Cable_Status as OPEN (step S608). When the accumulated result pwr_sum is not greater than the predetermined threshold thrs_pwr_total_open, the post-processing circuit 114 compares the accumulated result pwr_sum with another predetermined threshold thrs_pwr_total_short (step S610). When the accumulated result pwr_sum is less than the predetermined threshold thrs_pwr_total_short, the post-processing circuit 114 identifies the cable status Cable_Status as SHORT (step S612). When the accumulated result pwr_sum is not less than the predetermined threshold thrs_pwr_total_short, the post-processing circuit 114 identifies the cable status Cable_Status as LOAD (step S614).

[0039] The accumulated result pwr_sum obtained by receiving the RX signal S_RX through the mixing circuit 110 without echo cancellation participating in the generation of the RX signal S_RX will be greater than the accumulated result pwr_sum obtained by receiving the RX signal S_RX through the mixing circuit 110 with echo cancellation participating in the generation of the RX signal S_RX. Regarding the case where the RX signal S_RX is received through the mixing circuit 110 without echo cancellation participating in the generation of the RX signal S_RX, the first value V1 is assigned to the predetermined threshold thrs_pwr_total_open, and the second value V2 (V2 < V1) is assigned to the predetermined threshold thrs_pwr_total_short. Regarding the case where the RX signal S_RX is received through the mixing circuit 110 with echo cancellation participating in the generation of the RX signal S_RX, the third value V3 (V3 < V1) is assigned to the predetermined threshold thrs_pwr_total_open, and the fourth value V4 (V4 < V2) is assigned to the predetermined threshold thrs_pwr_total_short.

[0040] Please note, Figure 6 The process shown is only for illustration and is not intended to be limiting of the present invention. In fact, any means capable of realizing cable status identification by checking the recorded sample values ​​of the RX signal S_RX (which is received by the hybrid circuit 110 during the period when the hybrid circuit 110 transmits the LTP signal S_LTP compliant with the IEEE 802.3 standard) falls within the scope of the present invention.

[0041] In addition to identifying the cable status of the Ethernet cable 103 , the real-time Ethernet cable diagnosis function proposed by the present invention can also identify the location (length) of the cable problem of the Ethernet cable 103 . Figure 7 is a flowchart of an operation procedure for recording sample values ​​of the RX signal S_RX for subsequent position detection according to an embodiment of the present invention. Figure 7 The steps shown are performed by the post-processing circuit 114. The steps do not have to be exactly the same as above provided that substantially the same results can be obtained. Figure 7. In step S702, the length is unknown. In step S704, the post-processing circuit 114 checks whether the connection between the local device 102 and the remote device 104 has been successfully established. If the connection status indicates that the connection has been successfully established, the post-processing circuit 114 determines that the length is unknown and ends the process (step S708). If the connection status indicates that the connection has not been successfully established, the post-processing circuit 114 performs initialization of the recording program (step S706), so that the recording program will be enabled (CDT_en=ENABLE), the hybrid echo cancellation circuit 116 can be enabled / used or disabled / bypassed (HYBRID_EC=off / on), and the recording index value REC_IDX will be initialized to a preset value (REC_IDX=0). In step S710, the post-processing circuit 114 checks whether the transmission of the LTP signal S_LTP has started by checking the status of one or more related signals (for example, the signal XMIT_LTP). When the state of the signal XMIT_LTP is true, it indicates that the transmission of the LTP signal S_LTP has begun, and the post-processing circuit 114 begins to record the sample values ​​CDP_REC[REC_IDX] of the RX signal S_RX output by the RX circuit (including the RX variable gain amplifier and the cropper 112) of the local device 102. These sample values ​​are the digital values ​​ADC_IN sequentially output by the received signal S_RX. The post-processing circuit 114 will continue to execute the recording process until the record index REC_IDX reaches the maximum value MAX_IDX (steps S712 and S714). When multiple sample values ​​CDP_REC[0]~CDP_REC[MAX_IDX-1] have been recorded (that is, the number of recorded sample values ​​is equal to MAX_IDX), the post-processing circuit 114 stops the recording process (CDT_en=DISABLE) and enables subsequent post-processing of cable problem location detection (steps S716 and S718). In some embodiments of the present invention, the post-processing circuit 114 is used to Figure 5 The recorded sample values ​​CDP_REC[0] to CDP_REC[MAX_IDX-1] of the cable status identification can be reused in Figure 7 Position detection shown.

[0042] Figure 8 FIG. 4 is a flowchart of an operation procedure of post-processing the sample values ​​of the recorded RX signal S_RX to perform location detection of a cable problem according to an embodiment of the present invention. Figure 8 The steps shown are performed by the post-processing circuit 114. The steps do not have to be exactly the same as above provided that substantially the same results can be obtained. Figure 8The RX signal S_RX includes sample values ​​CDP_REC[0], CDP_REC[1], ..., CDP_REC[MAX_IDX-2], CDP_REC[MAX_IDX-1] at different time points in the forward direction. That is, the time point at which the sample value CDP_REC[m] is obtained is later than the time point at which the sample value CDP_REC[n] is obtained, where m is greater than n. The post-processing circuit 114 is used to sequentially check the sample values ​​CDP_REC[0] to CDP_REC[MAX_IDX-1] in the backward direction to identify the location of the cable problem (e.g., open circuit or short circuit) of the Ethernet cable 103. That is, the post-processing circuit 114 first checks the sample value CDP_REC[m] (m>n) before checking the sample value CDP_REC[n], and the first sample value checked is CDP_REC[MAX_IDX-1].

[0043] The post-processing circuit 114 performs initialization of the position detection program in step S802, so that the index value idx is initialized to a preset value (idx = MAX_IDX-1), and the flag short_flag is initialized to a preset value (short_flag = DISABLE). In step S804, the post-processing circuit 114 checks whether the cable status is LOAD. When the cable status is OPEN or SHORT, the Ethernet cable 103 has a cable problem (e.g., open circuit or short circuit), and the process proceeds to step S806. In step S806, the post-processing circuit 114 sets a plurality of parameters (e.g., thrs_pwr, intercept, and slope) according to the cable status. Specifically, the differential of the reflected signal of the local device 102 and the impedance mismatch position can be used to perform open circuit / short circuit position diagnosis. In this embodiment, when the cable state is OPEN, the parameter thrs_pwr is set by a predetermined value (thrs_pwr = thrs_pwr_open), the parameter intercept is set by a predetermined value (intercept = intercept_open), and the parameter slope is set by a predetermined value (slope = slope_open); when the cable state is SHORT, the parameter thrs_pwr is set by a predetermined value (thrs_pwr = thrs_pwr_short), the parameter intercept is set by a predetermined value (intercept = intercept_short), and the parameter slope is set by a predetermined value (slope = slope_short).

[0044] As described above, when the echo cancellation is enabled / used (HYBRID_EC = on), the RX signal S_RX does not include the echo signal caused by the TX operation of the local device; when the echo cancellation is disabled / bypassed (HYBRID_EC = off), the RX signal S_RX includes the echo signal caused by the TX operation of the local device. Therefore, in some embodiments of the present invention, the predetermined values ​​thrs_pwr_open' and thrs_pwr_short may depend on the on / off state of the echo cancellation, for example, when the echo cancellation is enabled / used (HYBRID_EC = on), the predetermined values ​​thrs_pwr_open and thrs_pwr_short may be set to normal values, and when the echo cancellation is disabled / bypassed (HYBRID_EC = off), the predetermined values ​​thrs_pwr_open and thrs_pwr_short may be set to larger values, however, this is only for exemplary purposes and is not intended to be limiting of the present invention.

[0045] Fig. 9: is a diagram comparing the waveforms of the RX signal S_RX obtained at different positions (lengths) of the cable problem. Without echo cancellation, the positive reflection signal caused by the open circuit at a longer distance (e.g., 20m) of the cable problem will not be disturbed by the echo signal, and the negative reflection signal caused by the short circuit at a longer distance (e.g., 20m) of the cable problem will not be disturbed by the echo signal. With echo cancellation, the positive reflection signal caused by the open circuit at a longer distance (e.g., 20m) of the cable problem and the negative reflection signal caused by the short circuit at a longer distance (e.g., 20m) of the cable problem will be symmetric. With echo cancellation, the positive reflection signal caused by the open circuit at a shorter distance (e.g., 0m) of the cable problem and the negative reflection signal caused by the short circuit at a shorter distance (e.g., 0m) of the cable problem will be symmetric, which allows the parameter thrs_pwr to be set to a normal value. However, without echo cancellation, the positive reflection signal and the echo signal caused by the open circuit when the cable problem is located at a shorter distance (e.g., 0m) will be constructive, which results in a larger total power of the observed signal; the negative reflection signal and the echo signal caused by the short circuit when the cable problem is located at a shorter distance (e.g., 0m) will be destructive, which results in a smaller total power of the observed signal. Therefore, in some embodiments of the present invention, when the cable status is SHORT and the echo cancellation is disabled / bypassed (HYBRID_EC=off), the parameter thrs_pwr can be set to a smaller value to identify the location of the cable problem. However, this is only for illustrative purposes and is not intended to be a limitation of the present invention.

[0046] The starting point LP_start of the LTP signal S_LTP is static, and the end point LP_END of the reflected signal in the RX signal S_RX corresponds to the length. In step S808, the post-processing circuit 114 attempts to find the end point LP_END by checking a specific condition. As described above, the post-processing circuit 114 identifies the location of the cable problem of the Ethernet cable 103 by sequentially checking the sample values ​​CDP_REC[MAX_IDX-1], CDP_REC[MAX_IDX-2], ..., CDP_REC[1], CDP_REC[0]. Therefore, the post-processing circuit 114 first checks whether the last recorded sample value CDP_REC[MAX_IDX-1] is greater than the threshold value thrs_pwr or less than the threshold value thrs_pwr. If the recorded sample value CDP_REC[MAX_IDX-1] is neither greater than the threshold value thrs_pwr nor less than the threshold value thrs_pwr, the end point LP_END is not updated by the current index value idx=MAX_IDX-1 and remains at a preset value (e.g., LP_END=0). Since the end point LP_END is not a non-zero value, the post-processing circuit 114 updates the index value idx by a decrement value of -1 (steps S810 and S812). In step S814, the post-processing circuit 114 checks whether the updated index value idx reaches zero. When the updated index value idx reaches zero, the post-processing circuit 114 identifies the cable status as unknown (step S822). When the updated index value idx does not reach zero, the post-processing circuit 114 executes step S808 to continue checking the next recorded sample value CDP_REC[MAX_IDX-2].

[0047] When the post-processing circuit 114 finds that the current sample value CDP_REC[idx] is greater than the threshold value thrs_pwr or less than the threshold value thrs_pwr, the current sample value CDP_REC[idx] will be identified as the end point of the reflection signal caused by the reflection of the LTP signal S_LTP, the end point LP_END will be updated by the index value idx, and the flag short_flag will be updated according to certain conditions. In this embodiment, the flag short_flag is used to prevent the observed RX signal from being misjudged when the total power of the LOAD state is less than thrs_pwr_total_short. Specifically, the flag short_flag is used to prevent the state misjudgment when the cable state is LOAD and the current sample value CDP_REC[idx] is less than the threshold value thrs_pwr. In this embodiment, when the cable status is OPEN, the flag short_flag is set to 0; when the cable status is not OPEN and the current sampling value CDP_REC[idx] is not less than the threshold thrs_pwr, the flag short_flag is set to 0, and the cable status is changed to SHORT; when the cable status is not OPEN and the current sampling value CDP_REC[idx] is less than the threshold thrs_pwr, the flag short_flag is set to 1.

[0048] When the end point LP_END is a non-zero value, the post-processing circuit 114 checks whether the cable state is OPEN or whether the flag short_flag is set to 1 (step S816). When the cable state is SHORT and the flag short_flag is set to 0, the post-processing circuit 114 identifies that the cable state is LOAD (step S820). When the cable state is OPEN or the flag short_flag is set to 1 (which means that the cable state is SHORT and the current sample value CDP_REC[idx] is less than the threshold thrs_pwr), the post-processing circuit 114 calculates the length tap (step S818), and then calculates the length (which indicates the location of the cable problem) according to the length tap and the parameters intercept and slope (step S824). In step S826 , the post-processing circuit 114 further checks whether the length obtained in step S824 exceeds a resolution limit. If the length exceeds the resolution limit, the post-processing circuit 114 identifies the cable status as unknown (step S822 ).

[0049] Please note, Figure 8The process shown is only for illustration and is not intended to be a limitation of the present invention. In fact, any means that can achieve position detection by checking the recorded sample values ​​of the RX signal S_RX (which is received by the hybrid circuit 110 during the period when the hybrid circuit 110 transmits the LTP signal S_LTP that complies with the IEEE 802.3 standard) falls within the scope of the present invention.

[0050] The above descriptions are only preferred embodiments of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. An Ethernet network device, comprising: A line test pulse generator circuit is used to generate a line test pulse signal that complies with the IEEE 802.3 standard; Hybrid circuits; A transmission circuit, used for transmitting the connection test pulse signal to the Ethernet cable through the hybrid circuit; A receiving circuit for receiving a receiving signal from the Ethernet cable during a period when the connection test pulse signal is transmitted through the hybrid circuit; as well as The post-processing circuit is used to perform cable diagnosis of the Ethernet cable according to the received signal.

2. The Ethernet network device as claimed in claim 1, wherein the connection test pulse signal is a fast connection pulse of auto-negotiation or a normal connection pulse of 10BASE-T.

3. The Ethernet device as claimed in claim 1, wherein the received signal comprises a plurality of sample values ​​at different time points, and the post-processing circuit is used to accumulate the plurality of sample values ​​to generate an accumulation result, and identify the cable status of the Ethernet cable according to the accumulation result.

4. The Ethernet device as claimed in claim 3, wherein the post-processing circuit is used to compare the accumulated result with a predetermined threshold value to identify the cable status of the Ethernet cable.

5. The Ethernet device as claimed in claim 3, wherein the received signal is received by the hybrid circuit with echo cancellation participating in the generation of the received signal.

6. The Ethernet device of claim 3, wherein the receive signal is received by the hybrid circuit without echo cancellation participating in the generation of the receive signal.

7. The Ethernet device as claimed in claim 1, wherein the received signal comprises a plurality of sample values ​​at different time points in a forward direction, and the post-processing circuit is used to identify the location of the cable problem of the Ethernet cable by sequentially checking the plurality of sample values ​​of the received signal in a reverse direction.

8. The Ethernet device as claimed in claim 7, wherein the post-processing circuit is used to sequentially check the plurality of sample values ​​of the received signal in the reverse direction by comparing each sample value of the plurality of sample values ​​with a predetermined threshold.

9. The Ethernet device as claimed in claim 7, wherein the received signal is received by the hybrid circuit with echo cancellation participating in the generation of the received signal.

10. The Ethernet device of claim 7, wherein the receive signal is received by the hybrid circuit without echo cancellation participating in the generation of the receive signal.

11. A method for diagnosing an Ethernet cable, comprising: Generates connection test pulse signals that comply with IEEE 802.3 standards; The connection test pulse signal is transmitted to the Ethernet cable through the hybrid circuit; receiving a reception signal from the Ethernet cable during a period when the connection test pulse signal is transmitted through the hybrid circuit; as well as A cable diagnosis of the Ethernet cable is performed according to the received signal.

12. The Ethernet cable diagnostic method as claimed in claim 11, wherein the connection test pulse signal is a fast connection pulse of auto-negotiation or a normal connection pulse of 10BASE-T.

13. The Ethernet cable diagnostic method of claim 11, wherein the received signal comprises a plurality of sample values ​​at different time points, and the step of performing cable diagnostics of the Ethernet cable according to the received signal comprises: Accumulating the plurality of sample values ​​to generate an accumulation result; and The cable status of the Ethernet cable is identified according to the accumulated result.

14. The Ethernet cable diagnostic method as claimed in claim 13, wherein the step of identifying the cable status of the Ethernet cable according to the accumulated result comprises: The accumulated result is compared with a predetermined threshold value to identify the cable status of the Ethernet cable.

15. The Ethernet cable diagnostic method as claimed in claim 13, wherein the receiving signal is received by the hybrid circuit with echo cancellation participating in the generation of the receiving signal.

16. The Ethernet cable diagnostic method of claim 13, wherein the received signal is received by the hybrid circuit without echo cancellation participating in the generation of the received signal.

17. The Ethernet cable diagnostic method of claim 11, wherein the received signal comprises a plurality of sample values ​​at different time points in a forward direction, and the step of performing cable diagnostics of the Ethernet cable according to the received signal comprises: The location of a cable problem in the Ethernet cable is identified by sequentially examining a plurality of sample values ​​of the received signal in a reverse direction.

18. The Ethernet cable diagnostic method of claim 17, wherein the step of identifying the location of the cable problem of the Ethernet cable by sequentially checking the plurality of sample values ​​of the received signal in the reverse direction comprises: Each sample value of the plurality of sample values ​​is compared with a predetermined threshold.

19. The Ethernet cable diagnostic method as claimed in claim 17, wherein the receiving signal is received by the hybrid circuit with echo cancellation participating in the generation of the receiving signal.

20. The Ethernet cable diagnostic method of claim 17, wherein the received signal is received by the hybrid circuit without echo cancellation participating in the generation of the received signal.

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