CN114760424A - Signal forwarding method, circuit, device and signal distribution testing device - Google Patents
Signal forwarding method, circuit, device and signal distribution testing device Download PDFInfo
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Abstract
The invention provides a signal forwarding method, a circuit, a device and a signal distribution testing device, wherein the signal forwarding method carries out linear compensation on an input analog video signal to realize corresponding compensation and recovery on signal amplitude reduction caused by one-to-multiple-path signal forwarding, meanwhile, the distributed n2 paths of analog video signals are output to a receiving terminal after signal processing, and the drive-by-wire signals reversely transmitted by the receiving terminal are analyzed, meanwhile, the analog video signal is transmitted to a signal transmitting circuit at the later stage and a drive-by-wire signal transmitted reversely at the later stage is received, one receiving terminal only needs to be connected with one signal transmitting circuit and one sending terminal to complete the test, and m receiving terminals only need to be connected with m signal transmitting circuits and one sending terminal to complete the test, so that the test cost is reduced, the test efficiency is improved, and meanwhile, the high-fidelity output of the analog video signal and the reverse transmission of the drive-by-wire signal are realized.
Description
Technical Field
The invention belongs to the technical field of signal processing, and particularly relates to a signal forwarding method, a signal forwarding circuit, a signal forwarding device and a signal distribution testing device.
Background
Currently, Video signals are classified into digital Video signals and analog Video signals according to types, such as a typical analog Video camera, and the output Video signals are transmitted by using an analog CVBS (Composite Video Broadcast Signal).
The CVBS signal has a composite characteristic that all components required for generating a video signal are combined in the same signal, specifically, the signal is composed of each field in series, the signal of each field contains components such as a line signal, a field sync, a field blanking, a coaxial line control, and the like, and the signal of each line contains components such as a line sync, a color component, a luminance component, a line blanking, and the like.
In the development and testing field of the video monitoring field, it is necessary to perform performance testing on a sending terminal corresponding to a receiving terminal of an analog video signal, for example, as a hard disk video recorder serving as the receiving terminal in fig. 1, a 16-channel hard disk video recorder is connected to 16 analog video cameras serving as the sending terminal, the 16 analog video cameras serve as monitoring front ends, respectively collect real-time video data of respective monitoring sites, and output the analog video signal to each video port of an analog high-definition hard disk video recorder connected to the rear end to perform preview monitoring and video recording of each channel video. In order to ensure the accuracy of a test result, an operator must set up a sufficient number of cameras in a test link in the field of equipment research and development and a production test quality inspection link in the field of equipment manufacturing, and then the cameras are connected to each video input port of the video recorder one to one.
All channels to be fully connected with the video recorder need to be provided with 16 cameras, so in the research and development and manufacturing fields, each development and testing personnel needs to be provided with 16 cameras, more testing resources and office areas can be occupied, particularly in the testing link, the situation is more prominent, the aging test of an equipment model machine generally needs to be provided with about 10 sets of quantity scales, therefore, for the model of the 16 channels, the aging test environment is provided with 160 cameras, the field wiring harness is difficult to avoid and complicated in arrangement, the testing equipment and a large-area testing area are seriously occupied, the later period of inspection and maintenance work is time-consuming and labor-consuming, the operation and maintenance are not convenient, and the efficiency is low.
Disclosure of Invention
The invention aims to provide a signal forwarding method, which aims to solve the problems of high cost and low efficiency in the test of terminal equipment and realize high-fidelity signal forwarding.
A first aspect of an embodiment of the present invention provides a signal forwarding method, which is applied to a signal forwarding circuit, where a plurality of signal forwarding circuits are cascaded, each signal forwarding circuit is connected to a receiving terminal, and the signal forwarding method includes:
acquiring an analog video signal output by a sending terminal or a front-stage signal forwarding circuit, and acquiring and analyzing a line control signal output by a receiving terminal connected with the front-stage signal forwarding circuit or acquiring a line control signal output by a rear-stage signal forwarding circuit;
performing linear compensation on the analog video signals, distributing the analog video signals into n1+1 paths, respectively performing signal processing, and outputting n2 paths of the analog video signals to n2 signal ports of the receiving terminal connected to the current stage and outputting one path of the analog video signals to the signal forwarding circuit connected to the subsequent stage, wherein n1 ≧ n2 ≧ 2;
and reversely outputting the drive-by-wire signal to the sending terminal or the preceding stage of the signal forwarding circuit.
Optionally, the acquiring and analyzing the line control signal output by the receiving terminal connected to the current stage specifically includes:
decoding the analog video signal and generating a driving signal;
identifying the vertical blanking in the analog video signal and generating an enabling signal;
and performing line control pulse superposition on the driving signal and the enabling signal and analyzing to generate the line control signal.
A second aspect of an embodiment of the present invention provides a signal forwarding circuit, including:
the compensation recovery circuit is used for connecting a sending terminal or the preceding signal forwarding circuit, acquiring the analog video signal output by the sending terminal or the preceding signal forwarding circuit, and performing signal linear compensation and distribution to n1+1 paths;
the n1+1 paths of bidirectional signal transmission circuits are connected with the output end of the compensation recovery circuit in common and receive the n1+1 paths of analog video signals one by one; wherein,
n1 paths of the bidirectional signal transmission circuit, wherein n2 paths of the bidirectional signal transmission circuit are connected with n2 signal ports of a receiving terminal connected with the stage, and after performing signal processing on each path of the analog video signal, n2 paths of the analog video signal are output to the receiving terminal connected with the stage, and a line control signal output by the receiving terminal connected with the stage is obtained and analyzed;
the other two-way signal transmission circuit is used for performing signal processing on the analog video signal output by the compensation recovery circuit, outputting the analog video signal to the post-stage signal forwarding circuit and acquiring a line control signal output by the post-stage signal forwarding circuit;
and each line control signal is reversely output to the sending terminal through the compensation recovery circuit.
Optionally, each of the bidirectional signal transmission circuits includes:
a first signal transmission circuit, a first end of which is connected to the compensation recovery circuit, a second end of which is connected to the receiving terminal of the current stage or the signal forwarding circuit of the next stage, and the first signal transmission circuit is configured to perform signal processing on the analog video signal output by the compensation recovery circuit and output the processed analog video signal to the receiving terminal of the current stage or the signal forwarding circuit of the next stage;
and the first end of the second signal transmission circuit is connected with the compensation recovery circuit, the second end of the second signal transmission circuit is connected with the receiving terminal or the post-stage signal forwarding circuit, and the second signal transmission circuit is used for analyzing the drive-by-wire signal output by the receiving terminal connected with the current stage or acquiring the drive-by-wire signal output by the post-stage signal forwarding circuit, and reversely outputting the drive-by-wire signal to the sending terminal or the pre-stage signal forwarding circuit through the compensation recovery circuit.
Optionally, the first signal transmission circuit includes:
the alternating current coupling circuit is connected with the compensation recovery circuit and is used for coupling and outputting the analog video signal;
the filtering driving circuit is connected with the alternating current coupling circuit and is used for filtering, amplifying and outputting the coupled and output analog video signals;
and the linear adjusting circuit is connected with the filtering driving circuit and the receiving terminal or the signal forwarding circuit at the current stage, and is used for linearly adjusting the filtered and amplified analog video signal and outputting the analog video signal with a preset amplitude.
Optionally, the second signal transmission circuit includes:
the drive-by-wire decoding circuit is connected with the receiving terminal at the current stage or the signal forwarding circuit at the later stage and is used for analyzing the reverse drive-by-wire signal in the analog video signal and generating a driving signal;
the vertical blanking synchronous circuit is connected with the line control decoding circuit and is used for identifying vertical blanking in the analog video signal and generating an enabling signal;
and the pulse superposition circuit is respectively connected with the drive-by-wire decoding circuit, the field blanking synchronous circuit and the compensation recovery circuit and is used for carrying out drive-by-wire pulse superposition on the drive signal and the enable signal and outputting the drive-by-wire signal.
Optionally, the signal forwarding circuit further includes:
the first electrostatic protection circuit is connected to the front stage of the compensation recovery circuit and is used for performing electrostatic protection on an input analog video signal or an output drive-by-wire signal;
and a first end of the second electrostatic protection circuit is connected with the receiving terminal or the post-stage signal forwarding circuit, a second end of the second electrostatic protection circuit is respectively connected with the first signal transmission circuit and the second signal transmission circuit, and the second electrostatic protection circuit is used for performing electrostatic protection on the output analog video signal or the input drive-by-wire signal.
Optionally, the signal forwarding circuit further includes:
and the power supply conversion circuit is used for converting and outputting a working power supply with a corresponding voltage to the bidirectional signal transmission circuit.
A third aspect of the embodiments of the present invention provides a signal forwarding apparatus, including the signal forwarding circuit described above.
A fourth aspect of the embodiments of the present invention provides a signal distribution testing apparatus, including m signal forwarding apparatuses as described above, where the m signal forwarding apparatuses are arranged in a cascade;
the signal forwarding devices at the first stage are connected with the sending terminal, and each signal forwarding device is connected with n2 signal ports of the receiving terminal.
Compared with the prior art, the embodiment of the invention has the following beneficial effects: the signal forwarding method carries out linear compensation on input analog video signals, realizes corresponding compensation and recovery on signal amplitude reduction caused by one-to-multiple forwarding of the signals, simultaneously outputs distributed n2 paths of analog video signals to a receiving terminal after signal processing, analyzes a drive-by-wire signal reversely transmitted by the receiving terminal, forwards the analog video signals to a signal forwarding circuit at the later stage and receives the drive-by-wire signal reversely transmitted by the later stage, one receiving terminal can complete testing only by being connected with one path of signal forwarding circuit and one sending terminal, m receiving terminals can complete testing only by being connected with m paths of signal forwarding circuits and one sending terminal, reduces testing cost, improves testing efficiency, and simultaneously realizes high-fidelity output of the analog video signals and reverse transmission of the drive-by-wire signal.
Drawings
Fig. 1 is a test diagram of a conventional transmission terminal and a test terminal;
fig. 2 is a schematic diagram of a first structure of a signal forwarding circuit according to an embodiment of the present invention;
fig. 3 is a schematic flowchart of a signal forwarding method according to an embodiment of the present invention;
fig. 4 is a schematic flowchart of step S10 in the signal forwarding method according to the embodiment of the present invention;
fig. 5 is a schematic diagram of a second structure of a signal forwarding circuit according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a third structure of a signal forwarding circuit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a fourth structure of a signal forwarding circuit according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a fifth structure of a signal forwarding circuit according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a sixth structure of a signal forwarding circuit according to an embodiment of the present invention;
fig. 10 is a circuit schematic diagram of a signal forwarding circuit according to an embodiment of the present invention;
fig. 11 is a schematic structural diagram of a signal distribution testing apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
A first aspect of the embodiment of the present invention provides a signal forwarding method, which is applied to a signal forwarding circuit 1, as shown in fig. 2, a plurality of signal forwarding circuits 1 are cascaded, and each signal forwarding circuit 1 is connected to a receiving terminal 3.
As shown in fig. 3, the signal transfer method corresponding to the signal transfer circuit 1 includes:
step S10, acquiring the analog video signal output by the sending terminal 2 or the preceding stage signal forwarding circuit 1, and acquiring and analyzing the line control signal output by the receiving terminal 3 connected to the current stage or acquiring the line control signal output by the succeeding stage signal forwarding circuit 1.
Step S20, performing linear compensation on the analog video signals, distributing the analog video signals into n1+1 paths, performing signal processing respectively, and outputting n2 paths of analog video signals to n2 signal ports of the receiving terminal 3 connected at the current stage and outputting one path of analog video signals to the subsequent-stage signal forwarding circuit 1, where n1 ≧ n2 ≧ 2;
step S30, the line control signal is reversely output to the transmission terminal 2 or the preceding stage signal transfer circuit 1.
In this embodiment, corresponding to the signal receiving, distributing, and forwarding functions, the signal forwarding circuit 1 is provided with a first port IO1 for connecting the transmitting terminal 2 or the preceding stage signal forwarding circuit 1, a second port IO2 for connecting the receiving terminal 3, and a forwarding port IO3 for connecting the succeeding stage signal forwarding circuit 1.
The signal forwarding circuit 1 implements distribution and forwarding of analog video signals by using a signal forwarding method, and also implements analysis and reverse output of line control signals.
That is, the analog video signal sent by the sending terminal 2 or the analog video signal forwarded and output by the signal forwarding circuit 1 at the previous stage is received through the first port IO1, and meanwhile, in order to obtain the high fidelity of the signal-to-multi-path forwarding processing, according to the establishment principle and the constitution characteristics of the CVBS signal, the position of the signal forwarding sampling point VA is improved, the star-shaped sampling point VA for signal forwarding is moved forward and is set after linear compensation, the signal amplitude change at the star-shaped sampling point VA is only related to the distribution quantity, that is, only related to the forwarding path number, and meanwhile, the star-shaped sampling point VA is provided with a corresponding compensation module to realize linear compensation, and realize the corresponding compensation and recovery of the signal amplitude reduction caused by the signal-to-multi-path forwarding, thereby realizing the signal fidelity at the sampling point VA, and the adjustment of the compensation parameter of the advanced compensation can be flexibly adjusted according to the forwarding path number due to the forward movement of the sampling point VA, the compatibility is improved.
After the analog video signals are compensated and restored to original signals at the star-shaped sampling point VA, multiple paths of analog video signals are distributed, and each path of analog video signal is subjected to optimization processing such as filtering amplification and linear adjustment to obtain expected high-fidelity analog video signals, and the expected high-fidelity analog video signals are output to n2 signal ports of the sending terminal 2 through the second port IO2 respectively, so that the receiving terminal 3 performs video monitoring or data statistics.
Meanwhile, the high-fidelity analog video signal is further forwarded to the subsequent signal forwarding circuit 1 through the forwarding port IO3 to provide the analog video signal to each subsequent signal forwarding circuit 1, so that the analog video signal is forwarded step by step.
Meanwhile, the analog video signal is formed by multi-component high composition, not only contains the forward transmission video signal, but also modulates the line control signal in the field blanking area for reverse transmission, for example, the video camera can modulate the reverse line control signal to the field blanking area of the CVBS signal to complete the reverse control of the video recorder on the analog video camera, and realize the functions of screen menu display, remote parameter configuration and the like.
Therefore, in order to realize the reverse output of the line control signal, in the signal forwarding method, when the corresponding line control signal is received and analyzed through the second port IO2 or the third port, that is, when the second port IO2 signal is distributed, the control signal forwarding circuit 1 analyzes the line control signal reversely output by the receiving terminal 3 connected to the current stage, and at the same time, receives the line control signal output by the subsequent stage signal forwarding circuit 1 through the forwarding port IO3, and controls the signal forwarding circuit 1 to perform corresponding signal processing on the line control signal, and then reversely output to the first port IO1, and further output to the transmitting terminal 2 or the signal forwarding circuit 1 at the previous stage.
Optionally, as shown in fig. 4, the acquiring and analyzing the line control signal output by the receiving terminal 3 connected to the current stage specifically includes:
step S11, decoding the analog video signal and generating a driving signal;
step S12, identifying the vertical blanking in the analog video signal and generating an enabling signal;
and step S13, performing line control pulse superposition on the driving signal and the enabling signal, and analyzing to generate a line control signal.
In this embodiment, the corresponding decoding module analyzes the reverse line control signal in the analog video signal, so as to capture the line control signal from the analog video signal, generate the driving signal, and at the same time, the corresponding vertical blanking module is set to complete vertical blanking identification of the analog video signal, generate the enable signal and output 123, so as to provide a working reference for the pulse superposition module, and the pulse superposition module completes line control pulse superposition on the input signal, so that the line control signal of the receiving terminal 3 is decoded and synchronized, and then reversely transmitted to the first port IO1 and the sending terminal 2.
The linear compensation is carried out on the input analog video signals, the corresponding compensation and recovery of signal amplitude reduction caused by one-to-multiple forwarding of the signals are realized, meanwhile, the distributed n2 paths of analog video signals are output to the receiving terminal 3 after signal processing, the drive-by-wire signals reversely transmitted by the receiving terminal 3 are analyzed, meanwhile, the analog video signals are forwarded to the signal forwarding circuit 1 at the rear stage and the drive-by-wire signals reversely transmitted by the rear stage are received, one receiving terminal 3 can complete the test only by being connected with one path of signal forwarding circuit 1 and one sending terminal 2, the m receiving terminals 3 can complete the test only by being connected with the m paths of signal forwarding circuits 1 and one sending terminal 2, the test cost is reduced, the test efficiency is improved, and meanwhile, the high-fidelity output of the analog video signals and the reverse transmission of the drive-by-wire signals are realized.
The internal structure of the signal forwarding circuit 1 may be set correspondingly according to the signal processing, distributing, and forwarding functions, and the specific structure is not limited.
Based on the working principle of the signal forwarding method, as shown in fig. 5, a second aspect of the embodiment of the present invention provides a signal forwarding circuit 1, including:
a compensation restoring circuit 200, wherein the compensation restoring circuit 200 is used for connecting the transmitting terminal 2 or the preceding signal forwarding circuit 1, acquiring the analog video signal output by the transmitting terminal 2 or the preceding signal forwarding circuit 1, and performing linear compensation and distribution of the signal into n1+1 paths;
an n1+ 1-path bidirectional signal transmission circuit 100 which is connected with the output end of the compensation recovery circuit 200 and receives the n1+ 1-path analog video signals one by one; wherein,
the n2 bidirectional signal transmission circuits 100 of the n1 bidirectional signal transmission circuits 100 are connected to the n2 signal ports of the receiving terminal 3 connected to the current stage, and output n2 analog video signals to the receiving terminal 3 connected to the current stage after performing signal processing on each analog video signal, and acquire and analyze the line control signal output by the receiving terminal 3 connected to the current stage;
the other two-way signal transmission circuit 100 is configured to perform signal processing on the analog video signal output by the compensation recovery circuit 200, output the analog video signal to the subsequent signal forwarding circuit 1, and acquire a drive-by-wire signal output by the subsequent signal forwarding circuit 1;
each line control signal is reversely output to the transmission terminal 2 through the compensation recovery circuit 200.
In this embodiment, the signal forwarding circuit 1 implements one-to-many distribution and forwarding functions, implements high-fidelity forwarding of analog video signals, and reversely outputs line control signals, and the signal forwarding circuit 1 is provided with a first port IO1 for connecting the sending terminal 2 or the preceding stage signal forwarding circuit 1, a second port IO2 for connecting the receiving terminal 3, and a forwarding port IO3 for connecting the subsequent stage signal forwarding circuit 1, corresponding to the signal receiving, distribution, and forwarding functions.
The signal forwarding circuit 1 adopts a signal forwarding method to realize distribution and forwarding of analog video signals and simultaneously realize analysis and reverse output of line control signals.
That is, the first port IO1 is used to receive the analog video signal sent by the sending terminal 2 or the analog video signal forwarded and output by the signal forwarding circuit 1 at the previous stage, and at the same time, in order to obtain the high fidelity of the signal-to-multi-path forwarding processing, the position of the signal forwarding sampling point VA is improved according to the establishment principle and the constitution characteristics of the CVBS signal, the star-type sampling point VA for signal forwarding is moved forward and is arranged behind the compensation recovery circuit 200, the signal amplitude change at the star-type sampling point VA is only related to the distribution quantity, that is, only related to the forwarding path quantity, and at the same time, the corresponding compensation recovery circuit 200 is arranged at the star-type sampling point VA to realize the linear compensation, and realize the corresponding compensation recovery to the signal amplitude reduction caused by the signal-to-multi-path forwarding, thereby realizing the signal fidelity at the sampling point VA, and the compensation parameter allocation of the compensation recovery circuit 200 can be flexibly allocated according to the forwarding path quantity due to the forward movement of the sampling point VA, the compatibility is improved.
After the analog video signals are compensated and restored to original signals at the star-shaped sampling point VA, multiple paths of analog video signals are distributed, and each path of analog video signal is subjected to optimization processing such as filtering amplification and linear adjustment by each bidirectional signal transmission circuit 100 to obtain expected high-fidelity analog video signals, and the expected high-fidelity analog video signals are output to n2 signal ports of the sending terminal 2 through the second port IO2 respectively, so that the receiving terminal 3 performs video monitoring or data statistics.
Meanwhile, the high-fidelity analog video signal is forwarded to the subsequent signal forwarding circuit 1 through a one-path bidirectional signal transmission circuit 100 forwarding port IO3 to provide the analog video signal to each subsequent signal forwarding circuit 1, so that the analog video signal is forwarded step by step, and during testing, a plurality of receiving terminals 3 are matched with one sending terminal 2 and a plurality of signal forwarding circuits 1 to complete performance testing, thereby reducing testing cost and improving testing efficiency.
Meanwhile, the analog video signal is formed by multi-component high composition, not only contains the forward transmission video signal, but also modulates the line control signal in the field blanking area for reverse transmission, for example, the video camera can modulate the reverse line control signal to the field blanking area of the CVBS signal to complete the reverse control of the video recorder on the analog video camera, and realize the functions of screen menu display, remote parameter configuration and the like.
Therefore, in order to realize the reverse output of the line control signal, when the bidirectional signal transmission circuit 100 receives and analyzes the corresponding line control signal through the second port IO2 or the third port, that is, when the second port IO2 signal is distributed, the bidirectional signal transmission circuit 100 analyzes the line control signal reversely output by the receiving terminal 3 connected to the current stage, and at the same time, receives the line control signal output by the subsequent stage signal forwarding circuit 1 through the forwarding port IO3, and performs corresponding signal processing on the line control signal, and then reversely outputs the line control signal to the first port IO1, and further outputs the line control signal to the transmitting terminal 2 or the previous stage signal forwarding circuit 1, thereby finally realizing the reverse control of the transmitting terminal 2, and completing the operations such as parameter configuration and zoom control.
One signal forwarding circuit 1 may be connected to at least one receiving terminal 3, and may be connected to different types of receiving terminals 3, where the number of the signal ports P1 to Pn2 is 2 to n1, so as to improve test compatibility, and the number of the second port IO2 and the number of the bidirectional signal transmission circuits 100 of the signal forwarding circuit 1 may be set correspondingly according to the receiving terminals 3.
After an analog video signal is input from one path, the analog video signal is forwarded in multiple paths, the input impedance at the star-shaped sampling point VA becomes small, the amplitude of the signal is correspondingly reduced, the compensation recovery circuit 200 is used for compensating for the reduction of the input impedance at the star-shaped sampling point VA, linear compensation is completed on the amplitude of the input signal, optionally, the compensation recovery circuit 200 is composed of resistors, the number of distribution paths is different, the models of filter drivers U1 are different, the reduction of the input impedance at the star-shaped sampling point VA is also correspondingly different, optionally, as shown in fig. 10, the compensation recovery circuit 200 includes a second resistor R2 and a third resistor R3 which are connected in series.
The specific structure of the bidirectional signal transmission circuit 100 may be set correspondingly according to the signal processing requirements of the analog video signal and the line control signal, and a compensation circuit, a decoding circuit, etc. may be set correspondingly, and the specific structure is not limited.
As shown in fig. 6, optionally, each bidirectional signal transmission circuit 100 includes:
the first signal transmission circuit 110, a first end of the first signal transmission circuit 110 is connected to the compensation recovery circuit 200, a second end of the first signal transmission circuit 110 is connected to the current-stage receiving terminal 3 or the subsequent-stage signal forwarding circuit 1, and the first signal transmission circuit 110 is configured to perform signal processing on the analog video signal output by the compensation recovery circuit 200 and output the processed analog video signal to the current-stage receiving terminal 3 or the subsequent-stage signal forwarding circuit 1;
a second signal transmission circuit 120, a first end of the second signal transmission circuit 120 is connected to the compensation restoring circuit 200, a second end of the second signal transmission circuit 120 is connected to the current stage receiving terminal 3 or the next stage signal forwarding circuit 1, and the second signal transmission circuit 120 is configured to analyze the line control signal output by the current stage receiving terminal 3 or acquire the line control signal output by the next stage signal forwarding circuit 1, and reversely output the line control signal to the sending terminal 2 or the previous stage signal forwarding circuit 1 through the compensation restoring circuit 200.
In this embodiment, the first signal transmission circuit 110 completes the forward distribution work of the analog video signal, the second signal transmission circuit 120 implements the reverse transmission work of the line control signal, the first signal transmission circuit 110 completes the signal processing such as filtering amplification and linear adjustment of the analog signal, thereby implementing the maximum fidelity of the video signal, and the second signal transmission circuit 120 completes the operations such as line control decoding, field blanking synchronization, pulse superposition, and the like of the analog video signal, thereby implementing the return transmission of the line control signal to the sending terminal 2.
The first signal transmission circuit 110 and the second signal transmission circuit 120 are specifically configured according to a signal forward distribution function and a reverse transmission function of a line control signal, and the specific structure is not limited.
As shown in fig. 7, optionally, the first signal transmission circuit 110 includes:
the alternating current coupling circuit 111, the alternating current coupling circuit 111 is connected with the compensation recovery circuit 200, and couples and outputs the analog video signal;
the filter driving circuit 112 is connected with the ac coupling circuit 111, and the filter driving circuit 112 is configured to perform filtering amplification processing on the coupled and output analog video signal and output the analog video signal;
and a linear adjusting circuit 113 connected to the filter driving circuit 112 and the current-stage receiving terminal 3 or the subsequent-stage signal forwarding circuit 1, where the linear adjusting circuit 113 is configured to linearly adjust the filtered and amplified analog video signal and output an analog video signal with a preset amplitude.
In this embodiment, the ac coupling circuit 111 is configured to implement coupling output of an analog video signal and cooperate with the filter driving circuit 112 to obtain low noise performance, as shown in fig. 8, optionally, the ac coupling circuit 111 includes a capacitor C1, and the capacitor C1 is connected in series between the first port IO1 and the filter driving circuit 112.
The filter driving circuit 112 performs filtering of high-frequency noise introduced by a power supply, a line, a cable and the like on a signal output by the ac coupling circuit 111 on one hand, and completes signal amplification on the other hand, the linear adjustment circuit 113 adapts to the amplification capability of the filter driving circuit 112 to linearly adjust the composite video signal to a preset size, wherein, as shown in fig. 10, the filter driving circuit 112 includes a filter driver U1, the linear adjustment circuit 113 includes a first resistor R1, and the first resistor R1 is connected in series between the filter driver U1 and the second port IO2 or the forwarding port IO 3.
Meanwhile, the filter driver U1 of the corresponding model is selected according to the type and the resolution of the analog video signal, the value of the capacitor C1 of the AC coupling circuit 111 is selected according to the coupling bandwidth of the filter driver U1, the first resistor R1 is selected according to the amplification factor of the filter driver U1, and the resistance value of the first resistor R1 and the capacitance value of the capacitor C1 are correspondingly adjusted, so that the amplitude of the input signal of the filter driver U1 is approximate to the amplitude of the output signal of the linear adjusting circuit 113.
Meanwhile, as shown in fig. 7, the second signal transmission circuit 120 optionally includes:
the second signal transmission circuit 120 includes:
the drive-by-wire decoding circuit 121 is connected with the receiving terminal 3 at the current stage or the signal forwarding circuit 1 at the later stage, and the drive-by-wire decoding circuit 121 is used for analyzing the reverse drive-by-wire signal in the analog video signal and generating a driving signal;
a vertical blanking synchronizing circuit 122 connected to the line control decoding circuit 121, the vertical blanking synchronizing circuit 122 identifying vertical blanking in the analog video signal and generating an enable signal;
and the pulse superposition circuit 123 is respectively connected with the drive-by-wire decoding circuit 121, the vertical blanking synchronous circuit 122 and the compensation recovery circuit 200 and is used for carrying out drive-by-wire pulse superposition on the driving signal and the enabling signal and outputting a drive-by-wire signal.
In this embodiment, in order to analyze the inverted line control signal in the analog video signal, a line control decoding circuit 121 is added, the line control decoding circuit 121 captures the line control signal from the analog video signal, generates a driving signal, and outputs the driving signal to the pulse superimposing circuit 123, and optionally, as shown in fig. 10, the line control decoding circuit 121 is formed by a single-channel high-speed comparator U3.
Specifically, since the inverted drive-by-wire signals are groups of pulse periodic waves in a field blanking region, the level amplitude is usually designed to be about 1V, and for enhancing compatibility, the reference voltage V1 at the inverted input end of the high-speed comparator U3 is set to be 800mV, and the output signal is connected to the forward input end of the comparator U3.
The vertical blanking synchronizing circuit 122 completes vertical blanking identification of the analog video signal, generates an enable signal and outputs the enable signal to the pulse superimposing circuit 123 to provide a working reference for the pulse superimposing circuit 123, and optionally, the vertical blanking synchronizing circuit 122 is formed by a single-channel high-speed comparator U3, that is, the high-speed comparator U3 completes signal conversion of line control signal decoding and vertical blanking synchronization to form a common group.
Specifically, since the level amplitude of the field blanking signal is 300mV, the comparator U3 reference voltage V2 of the field blanking synchronization circuit 122 needs to be set higher than 300mV, and alternatively, the reference voltage V2 is set to 330 mV.
The pulse superimposing circuit 123 completes the pulse superimposing of the line control input signal, so that the line control signal of the receiving terminal 3 is decoded and synchronized, and then reversely transmitted to the first port IO1 and the sending terminal 2, and optionally, as shown in fig. 10, the pulse superimposing circuit 123 is composed of an analog switch U2, an NPN type triode Q1, and a sixth resistor R6.
As shown in fig. 8, optionally, the signal forwarding circuit 1 further includes:
the first electrostatic protection circuit 300 connected to the front stage of the compensation recovery circuit 200, the first electrostatic protection circuit 300, is used for performing electrostatic protection on the input analog video signal or the output line control signal;
a first end of the second electrostatic protection circuit 400 is connected to the current stage receiving terminal 3 or the subsequent stage signal forwarding circuit 1, a second end of the second electrostatic protection circuit 400 is connected to the first signal transmission circuit 110 and the second signal transmission circuit 120, respectively, and the second electrostatic protection circuit 400 is configured to perform electrostatic protection on the output analog video signal or the input line control signal.
In this embodiment, the first electrostatic protection circuit 300 and the second electrostatic protection circuit 400 are used for performing electrostatic protection on corresponding ports, and prevent external static from entering and causing circuit damage through electrostatic discharge introduced to the ports, wherein the electrostatic protection circuits are distributed at the input end and the output end of the signal forwarding circuit 1, and the electrostatic protection circuits can select unidirectional TVS transistors or other types of protection devices.
As shown in fig. 9, optionally, the signal forwarding circuit 1 further includes:
the power conversion circuit 500, is configured to convert and output a working power with a corresponding voltage to the bidirectional signal transmission circuit 100.
In this embodiment, the power conversion circuit 500 obtains an external power through the power port IO4 and converts and outputs at least one operating power to each circuit inside the signal forwarding circuit 1, so that the internal circuit implements corresponding operations such as signal processing and transmission.
The power conversion circuit 500 may adopt a buck-boost circuit, a voltage stabilizing circuit, a DC/DC conversion circuit, and the like, and the specific structure is not limited.
Meanwhile, the power conversion circuit 500 may further be internally provided with a corresponding filter circuit to realize a planar filtering function, the filter circuit may be formed by a patch ceramic capacitor, and the capacitance value of the patch ceramic capacitor is comprehensively selected according to the operating frequency ranges of the power conversion circuit 500 and the filter driver U1, and the specific size is not limited.
As shown in fig. 11, the signal forwarding apparatus 1000 includes the signal forwarding apparatus 1000, and the specific structure of the signal forwarding apparatus 1000 refers to the foregoing embodiments, and since the signal forwarding apparatus 1000 adopts all technical solutions of all the foregoing embodiments, at least all beneficial effects brought by the technical solutions of the foregoing embodiments are achieved, and are not described in detail herein.
In this embodiment, the first port IO1, the second port IO2, and the forwarding port IO3 are integrally disposed on the signal forwarding apparatus 1000, and a corresponding port structure is adopted to connect the transmitting terminal 2, the receiving terminal 3, and the subsequent signal forwarding apparatus 1000, and each circuit in the signal forwarding circuit 1 is disposed on a circuit board of the signal forwarding apparatus 1000 and electrically connected to a corresponding port, so as to implement the transmitting and receiving operations of the analog video signal and the line control signal.
Meanwhile, when the signal forwarding device 1000 is used for testing the receiving terminal 3, one receiving terminal 3 only needs to be connected with one signal forwarding device 1000 and one sending terminal 2 to complete the test, and m receiving terminals 3 only need to be connected with m signal forwarding devices 1000 and one sending terminal 2 to complete the test, so that the test cost is reduced, and the test efficiency is improved.
The present invention further provides a signal distribution testing apparatus, which includes m signal forwarding apparatuses 1000, and the specific structure of the signal forwarding apparatus 1000 refers to the above embodiments, and since the signal distribution testing apparatus adopts all technical solutions of all the above embodiments, the signal distribution testing apparatus at least has all beneficial effects brought by the technical solutions of the above embodiments, and details are not repeated herein. Wherein, m signal forwarding devices 1000 are arranged in cascade;
the signal transfer device 1000 at the head stage is connected to the transmission terminal 2, and each signal transfer device 1000 is connected to the n2 signal ports P1 to Pn2 of the reception terminal 3.
In this embodiment, the signal forwarding devices 1000 are cascaded to form a signal distribution testing device, a one-to-many connection and signal distribution work between the sending terminal 2 and the multiple receiving terminals 3 is formed, and a sending terminal 2 is matched to form a testing device, so as to realize a synchronous test on the multiple receiving terminals 3, m receiving terminals 3 can complete a test only by connecting m paths of signal forwarding devices 1000 and one sending terminal 2, thereby reducing the testing cost and improving the testing efficiency, and meanwhile, each receiving terminal 3 can also send a line control signal to the sending terminal 2 through the corresponding signal forwarding device 1000, so as to realize a many-to-one time sharing control.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
1. A signal forwarding method is applied to a signal forwarding circuit, and is characterized in that a plurality of signal forwarding circuits are cascaded, each signal forwarding circuit is connected with a receiving terminal, and the signal forwarding method comprises the following steps:
acquiring an analog video signal output by a sending terminal or a front-stage signal forwarding circuit, and acquiring and analyzing a line control signal output by a receiving terminal connected with the front-stage signal forwarding circuit or acquiring a line control signal output by a rear-stage signal forwarding circuit;
performing linear compensation on the analog video signals, distributing the analog video signals into n1+1 paths, respectively performing signal processing, and outputting n2 paths of the analog video signals to n2 signal ports of the receiving terminal connected to the current stage and outputting one path of the analog video signals to the signal forwarding circuit connected to the subsequent stage, wherein n1 ≧ n2 ≧ 2;
and reversely outputting the line control signal to the sending terminal or the front stage of the signal forwarding circuit.
2. The signal forwarding method according to claim 1, wherein the acquiring and analyzing the line control signal output by the receiving terminal connected to the current stage specifically comprises:
decoding the analog video signal and generating a driving signal;
identifying the vertical blanking in the analog video signal and generating an enabling signal;
and performing line control pulse superposition on the driving signal and the enabling signal and analyzing to generate the line control signal.
3. A signal repeating circuit, comprising:
the compensation recovery circuit is used for connecting a sending terminal or a preceding-stage signal forwarding circuit, acquiring an analog video signal output by the sending terminal or the preceding-stage signal forwarding circuit, and performing linear compensation and distribution on the signal into n1+1 paths;
the n1+1 paths of bidirectional signal transmission circuits are connected with the output end of the compensation recovery circuit in common and receive the n1+1 paths of analog video signals one by one; wherein,
n1 paths of the bidirectional signal transmission circuit, wherein n2 paths of the bidirectional signal transmission circuit are connected with n2 signal ports of a receiving terminal connected with the stage, and after performing signal processing on each path of the analog video signal, n2 paths of the analog video signal are output to the receiving terminal connected with the stage, and a line control signal output by the receiving terminal connected with the stage is obtained and analyzed;
the other two-way signal transmission circuit is used for performing signal processing on the analog video signal output by the compensation recovery circuit, outputting the analog video signal to the post-stage signal forwarding circuit and acquiring a line control signal output by the post-stage signal forwarding circuit;
and each line control signal is reversely output to the sending terminal through the compensation recovery circuit.
4. The signal repeating circuit of claim 3, wherein each of said bidirectional signal transmitting circuits comprises:
a first signal transmission circuit, a first end of which is connected to the compensation recovery circuit, a second end of which is connected to the receiving terminal of the current stage or the signal forwarding circuit of the next stage, and the first signal transmission circuit is configured to perform signal processing on the analog video signal output by the compensation recovery circuit and output the processed analog video signal to the receiving terminal of the current stage or the signal forwarding circuit of the next stage;
and the first end of the second signal transmission circuit is connected with the compensation recovery circuit, the second end of the second signal transmission circuit is connected with the receiving terminal or the post-stage signal forwarding circuit, and the second signal transmission circuit is used for analyzing the drive-by-wire signal output by the receiving terminal connected with the current stage or acquiring the drive-by-wire signal output by the post-stage signal forwarding circuit, and reversely outputting the drive-by-wire signal to the sending terminal or the pre-stage signal forwarding circuit through the compensation recovery circuit.
5. The signal repeating circuit of claim 4, wherein the first signal transmission circuit comprises:
the alternating current coupling circuit is connected with the compensation recovery circuit and is used for coupling and outputting the analog video signal;
the filtering driving circuit is connected with the alternating current coupling circuit and is used for filtering, amplifying and outputting the coupled and output analog video signals;
and the linear adjusting circuit is connected with the filtering driving circuit and the receiving terminal or the signal forwarding circuit at the current stage, and is used for linearly adjusting the filtered and amplified analog video signal and outputting the analog video signal with a preset amplitude.
6. The signal forwarding circuit of claim 4, wherein the second signal transmission circuit comprises:
the drive-by-wire decoding circuit is connected with the receiving terminal at the current stage or the signal forwarding circuit at the later stage and is used for analyzing the reverse drive-by-wire signal in the analog video signal and generating a driving signal;
the vertical blanking synchronous circuit is connected with the line control decoding circuit and is used for identifying vertical blanking in the analog video signal and generating an enabling signal;
and the pulse superposition circuit is respectively connected with the drive-by-wire decoding circuit, the field blanking synchronous circuit and the compensation recovery circuit and is used for carrying out drive-by-wire pulse superposition on the drive signal and the enable signal and outputting the drive-by-wire signal.
7. The signal repeating circuit of claim 4, wherein the signal repeating circuit further comprises:
the first electrostatic protection circuit is connected to the front stage of the compensation recovery circuit and is used for performing electrostatic protection on an input analog video signal or an output drive-by-wire signal;
and a first end of the second electrostatic protection circuit is connected with the receiving terminal or the post-stage signal forwarding circuit, a second end of the second electrostatic protection circuit is respectively connected with the first signal transmission circuit and the second signal transmission circuit, and the second electrostatic protection circuit is used for performing electrostatic protection on the output analog video signal or the input drive-by-wire signal.
8. The signal repeating circuit of claim 3, wherein the signal repeating circuit further comprises:
and the power supply conversion circuit is used for converting and outputting a working power supply with a corresponding voltage to the bidirectional signal transmission circuit.
9. A signal transfer apparatus comprising a signal transfer circuit according to any one of claims 3 to 8.
10. A signal distribution test apparatus comprising m signal forwarding apparatuses according to claim 9, wherein m signal forwarding apparatuses are arranged in cascade, and m ≧ 2;
the signal forwarding devices at the first stage are connected with the sending terminal, and each signal forwarding device is connected with n2 signal ports of the receiving terminal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210299599.8A CN114760424A (en) | 2022-03-25 | 2022-03-25 | Signal forwarding method, circuit, device and signal distribution testing device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210299599.8A CN114760424A (en) | 2022-03-25 | 2022-03-25 | Signal forwarding method, circuit, device and signal distribution testing device |
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| CN114760424A true CN114760424A (en) | 2022-07-15 |
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| CN202210299599.8A Pending CN114760424A (en) | 2022-03-25 | 2022-03-25 | Signal forwarding method, circuit, device and signal distribution testing device |
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| CN (1) | CN114760424A (en) |
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