A relay circuit for wired pulse code modulation signals and a rocket telemetry system

Abstract

This invention provides a relay circuit for wired pulse code modulation signals and a rocket telemetry system. The relay circuit includes: an isolation drive circuit electrically connected to the rocket telemetry system; a signal conditioning circuit electrically connected to the isolation drive circuit; and a back-end regeneration drive circuit electrically connected to the signal conditioning circuit. The technical solution of this invention can prevent external interference and ground loop interference, achieving effective circuit isolation.

Description

Technical Field

[0001] This utility model relates to the field of data communication technology, and in particular to a relay circuit for wired pulse code modulation signals and a rocket telemetry system. Background Technology

[0002] In rocket telemetry systems, data from various sensors and subsystems are encoded using Pulse Code Modulation (PCM) and then transmitted to ground telemetry stations via cable networks. With the increasing distribution of electronic systems and longer transmission distances, signals face several severe challenges during long-distance transmission: 1. Signal attenuation and distortion: After passing through multiple connectors or branches, impedance changes over long distances can cause PCM signal amplitude attenuation and slower edges, resulting in inter-symbol interference, which is particularly severe at high code rates (e.g., 10 Mbps). 2. Ground potential difference and common-mode interference: The rocket's massive structure creates potential differences between grounding points of different equipment. Engine ignition and high-power equipment switching introduce strong common-mode noise, which can lead to bit errors or even damage interface circuits. 3. Electromagnetic compatibility (EMC) issues: The complex onboard electromagnetic environment can easily interfere with signal transmission. For example, onboard power distribution lines, parallel binding lines, or radio frequency signals can all couple onto the PCM signal. 4. Reliability requirements: It must have protection against electrostatic discharge (ESD), surge, extreme vibration, large temperature difference, and strong electromagnetic interference to ensure stable operation in harsh environments.

[0003] Existing relay solutions mostly use simple RS422 transceivers (such as AM26C31 / 32) for signal amplification. Although this can extend the distance to a certain extent, it lacks effective electrical isolation, cannot solve the ground loop interference problem, and has shortcomings in common-mode interference immunity, transmission rate, and integrated protection. Other solutions use optocouplers and discrete transceivers, but optocouplers have slow signal transmission speed, limited bandwidth, complex peripheral circuits, and high power consumption. In addition, optocouplers have problems such as temperature sensitivity and short lifespan in the harsh environment of rockets, resulting in low reliability. Utility Model Content

[0004] This invention provides a relay circuit for wired pulse code modulation (PCM) signals and a rocket telemetry system, which solves the problems of reduced signal integrity and insufficient reliability caused by attenuation, ground potential difference and electromagnetic interference during long-distance transmission of PCM signals in the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows: This utility model provides a relay circuit for wired pulse code modulation signals, comprising: An isolated drive circuit electrically connected to the rocket telemetry system; The signal conditioning circuit is electrically connected to the isolation drive circuit; The back-end regenerative drive circuit is electrically connected to the signal conditioning circuit. The wired pulse code modulation (PCM) data stream signal output by the rocket telemetry system is input to the isolation drive circuit. The isolation drive circuit performs isolation differential conversion processing on the PCM data stream signal and outputs a first-level signal. The first-level signal is input to the signal conditioning circuit, which performs differential buffering and shaping processing on the first-level signal and outputs a second-level signal. The second-level signal is input to the back-end regeneration drive circuit, which performs power amplification and waveform shaping on the second-level signal and outputs the PCM data stream signal.

[0006] Optionally, the isolated drive circuit includes: The first integrated isolation circuit receives the input PCM data stream signal through a third resistor; the resistance value of the third resistor is equal to the characteristic impedance of the cable. A first protection circuit is connected to the differential receiving end of the first integrated isolation circuit, and the other end of the first protection circuit is connected to a third ground wire; The third resistor is connected in parallel on the two differential input lines of the differential receiver of the first integrated isolation circuit; the first protection circuit filters out spike signals in the PCM data stream signal; the first integrated isolation circuit receives the PCM data stream signal and performs electrical isolation, and outputs a first level signal.

[0007] Optionally, the first integrated isolation circuit includes: The differential receiver converts the input PCM data stream signal into a single-ended logic signal with reference to the voltage of the third ground line; An isolated transmitter electrically connected to the output of the differential receiver modulates the single-ended logic signal into a first frequency electrical signal and drives a primary coupling unit electrically connected to the output of the isolated transmitter to convert the first frequency electrical signal into an alternating magnetic field signal. The secondary coupling unit, which is physically coupled to the primary coupling unit, senses the corresponding alternating magnetic field signal and converts it into a second frequency electrical signal. The isolation receiver, which is electrically connected to the secondary coupling unit, demodulates, regenerates, and eliminates jitter in the second frequency electrical signal, generates a first level signal with the voltage of the first ground line as a reference, and outputs it.

[0008] Optionally, the isolation receiver includes: The second frequency electrical signal is demodulated to obtain a baseband signal demodulator; A low-pass filter electrically connected to the output of the demodulator filters the baseband signal and outputs the original logic signal containing jitter. A clock data recovery circuit electrically connected to the output of the low-pass filter generates a clean clock signal based on the original logic signal. The data regeneration and buffer, which is electrically connected to the output of the clock data recovery circuit, clears the timing jitter in the original logic signal according to the pure clock signal and outputs a first level signal.

[0009] Optionally, the signal conditioning circuit includes a buffer circuit, the buffer circuit comprising: A Schmitt trigger receives a first-level signal, performs a hysteresis comparison on the input voltage, and outputs a digital signal. The output drive stage, which is electrically connected to the Schmitt trigger, amplifies the received digital signal and outputs a second-level signal.

[0010] Optionally, the back-end regeneration drive circuit includes at least one set, and each set of the back-end regeneration drive circuit includes: A second integrated isolation circuit and a second protection circuit; The second integrated isolation circuit amplifies and shapes the second level signal, and outputs the PCM data stream signal after passing through a set of bias resistors; the second protection circuit, which is electrically connected to the second integrated isolation circuit, resists electrostatic discharge at the output of the second integrated isolation circuit; the set of bias resistors includes a first resistor and a second resistor.

[0011] Optionally, the second integrated isolation circuit includes: The input buffer and level converter receives the second level signal, converts the second level signal into a preset operating voltage, provides preliminary noise margin, and outputs a standard second level signal. An isolation regeneration engine, electrically connected to the input buffer and level converter, performs electrical isolation, timing jitter elimination, and waveform regeneration on the standard second-level signal, and outputs an enhanced second-level signal. The differential driver, which is electrically connected to the isolated regeneration engine, receives the enhanced second-level signal, amplifies the enhanced second-level signal, and outputs the PCM data stream signal.

[0012] Optionally, the relay circuit for the wired pulse code modulation signal further includes: The power supply unit includes a power isolation module. The input terminal of the power isolation module is connected to an external 12V DC power supply, and the output terminal provides multiple isolated target voltages, which are respectively connected to the power input terminals of the isolation drive circuit, the signal conditioning circuit, and the back-end regeneration drive circuit.

[0013] This utility model also provides a rocket telemetry system, including: The relay circuit, front-end data acquisition unit, and back-end data processor of the wired pulse code modulation signal; The relay circuit is connected between the front-end data acquisition unit and the back-end data processor of the rocket telemetry system. It isolates, shapes, and amplifies the PCM data stream signal generated by the front-end data acquisition unit, and transmits the regenerated PCM data stream signal to the back-end data processor.

[0014] The above-described solution of this utility model has at least the following beneficial effects: The relay circuit for the wired pulse code modulation signal of this utility model includes: An isolated drive circuit electrically connected to the rocket telemetry system; The signal conditioning circuit is electrically connected to the isolation drive circuit; The back-end regenerative drive circuit is electrically connected to the signal conditioning circuit. The wired pulse code modulation (PCM) data stream signal output by the rocket telemetry system is input to the isolation drive circuit. The isolation drive circuit performs isolation differential conversion processing on the PCM data stream signal and outputs a first-level signal. The first-level signal is input to a signal conditioning circuit, which performs differential buffering and shaping processing on the first-level signal and outputs a second-level signal. The second-level signal is input to a back-end regeneration drive circuit, which amplifies the power and shapes the waveform of the second-level signal, and outputs the PCM data stream signal. This extends the signal transmission distance, prevents external interference and ground loop interference, and achieves effective circuit isolation. Attached Figure Description

[0015] Figure 1 This is a block diagram of the signal principle of the relay circuit for wired pulse code modulation signals according to this utility model. Figure 2 This is a circuit schematic diagram of the isolation drive circuit and signal conditioning circuit of this utility model; Figure 3 This is a circuit diagram of the back-end regeneration drive circuit of this utility model; Figure 4 This is a block diagram illustrating the power supply principle of the relay circuit for wired pulse code modulation signals according to this utility model. Figure 5This is a circuit diagram of the power supply for the relay circuit of the wired pulse code modulation signal according to this utility model.

[0016] Among them, 11 is the isolation drive circuit; 12 is the signal conditioning circuit; 13 is the back-end regeneration drive circuit; 14 is the power supply unit; U1 is the power isolation module; U2 is the second integrated isolation circuit; U3 is the first integrated isolation circuit; U4 is the second protection circuit; U5 is the buffer circuit; U6 is the first protection circuit; GND is the ground pin; GND1 is the first ground pin; GND2 is the second ground pin; GND3 is the first ground wire; GND4 is the second ground wire; GND5 is the third ground wire; R1 is the first resistor; R2 is the second resistor; R3 is the third resistor; +VIN is the positive voltage input pin; -VIN is the negative voltage input pin; +VOUT is the positive voltage output pin; -VOUT is the negative voltage output pin; C1 is the first capacitor; C2 is the second capacitor. C3, third capacitor; C4, fourth capacitor; C5, fifth capacitor; C6, sixth capacitor; C7, seventh capacitor; C8, eighth capacitor; C9, ninth capacitor; C10, tenth capacitor; C11, eleventh capacitor; C12, twelfth capacitor; C13, thirteenth capacitor; C14, fourteenth capacitor; C15, fifteenth capacitor; C16, sixteenth capacitor; C17, seventeenth capacitor; C18, eighteenth capacitor; C19, nineteenth capacitor; RXD, data input pin; TXD, data output pin; VISIN, video signal input pin; VISOUT, video signal output pin; DE, driver enable pin; RE, receiver enable pin; VCC, power input pin; A, differential bus input pin; Y, differential bus output pin. Detailed Implementation

[0017] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0018] like Figure 1 As shown, an embodiment of this utility model proposes a relay circuit for wired pulse code modulation signals, comprising: The isolated drive circuit 11 is electrically connected to the rocket telemetry system; Signal conditioning circuit 12 is electrically connected to the isolation drive circuit 11; The back-end regenerative drive circuit 13 is electrically connected to the signal conditioning circuit 12; The wired pulse code modulation (PCM) data stream signal output by the rocket telemetry system is input to the isolation drive circuit 11. The isolation drive circuit 11 performs isolation differential conversion processing on the PCM data stream signal and outputs a first-level signal. The first-level signal is input to the signal conditioning circuit 12. The signal conditioning circuit 12 performs differential buffering and shaping processing on the first-level signal and outputs a second-level signal. The second-level signal is input to the back-end regeneration drive circuit 13. The back-end regeneration drive circuit 13 performs power amplification and waveform shaping on the second-level signal and outputs the PCM data stream signal.

[0019] In this embodiment, the wired pulse code modulation (PCM) data stream signal is transmitted to the isolation drive circuit 11 for isolation differential conversion processing to obtain a first-level signal, which is then output to the signal conditioning circuit 12. The signal conditioning circuit 12 performs differential buffering and shaping processing on the first-level signal to obtain a second-level signal, which is then output to the back-end regeneration drive circuit 13. The back-end regeneration drive circuit 13 amplifies the power and shapes the waveform of the second-level signal to obtain the PCM data stream signal, which is then output. The isolation drive circuit 11 and the back-end regeneration drive circuit 13 can adopt the same circuit structure, and the back-end regeneration drive circuit includes at least one set.

[0020] By using the isolation barrier in the isolation drive circuit, the ground loop is cut off, preventing communication between different ground wires and protecting the safety of the front-end data acquisition unit and the back-end data processor, making it suitable for harsher industrial and aerospace environments.

[0021] like Figure 2 As shown, in an optional embodiment of the present invention, the isolation drive circuit 11 includes: The first integrated isolation circuit U3 receives the input PCM data stream signal through the third resistor R3; the resistance value of the third resistor R3 is equal to the characteristic impedance of the cable. A first protection circuit U6 is connected to the differential receiving terminal of the first integrated isolation circuit U3, and the other end of the first protection circuit U6 is connected to the third ground line GND5. The third resistor R3 is connected in parallel on the two differential input lines of the differential receiver of the first integrated isolation circuit U3; the first protection circuit U6 filters out spike signals in the PCM data stream signal; the first integrated isolation circuit U3 receives the PCM data stream signal and performs electrical isolation, and outputs a first level signal.

[0022] In this embodiment, the PCM data stream signal passes through a third resistor R3 with a resistance equal to the characteristic impedance of the cable to eliminate signal reflection, and then passes through a first protection circuit U6 to eliminate high voltage spike signals and protect subsequent circuits. The signal is transmitted through the differential input line of the differential receiver and enters the first integrated isolation circuit U3 for electrical isolation, and is then output to the signal conditioning unit through the data input pin RXD.

[0023] The target voltage is connected to the power input pin VCC of the first integrated isolation circuit U3. The first ground pin GND1 of the first integrated isolation circuit U3 is connected to the first ground line GND3. An eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13 and a fourteenth capacitor C14 are connected in parallel between the power input pin VCC and the first ground pin GND1. The video signal transceiver terminal of the first integrated isolation circuit U3 is connected to the third ground line GND5. The second ground pin GND2 of the first integrated isolation circuit U3 is also connected to the third ground line GND5. A fifteenth capacitor C15, a sixteenth capacitor C16, a seventeenth capacitor C17 and an eighteenth capacitor C18 are connected in parallel between the video signal transceiver terminal pin and the second ground pin GND2. The enable pin of the first integrated isolation circuit U3 is connected to the first ground line GND3; the data input pin RXD of the first integrated isolation circuit U3 is connected to the input terminal of the signal conditioning unit. The video signal transceiver of the first integrated isolation circuit U3 includes a video signal input pin VISIN and a video signal output pin VISOUT; the enable pins of the first integrated isolation circuit U3 include a driver enable pin DE and a receiver enable pin RE. The ground pin GND of the first protection circuit U6 is connected to the third ground line GND5.

[0024] In an optional embodiment of this utility model, the first integrated isolation circuit U3 includes: The differential receiver converts the input PCM data stream signal into a single-ended logic signal with reference to the voltage of the third ground line GND5. An isolated transmitter electrically connected to the output of the differential receiver modulates the single-ended logic signal into a first frequency electrical signal and drives a primary coupling unit electrically connected to the output of the isolated transmitter to convert the first frequency electrical signal into an alternating magnetic field signal. The secondary coupling unit, which is physically coupled to the primary coupling unit, senses the corresponding alternating magnetic field signal and converts it into a second frequency electrical signal. The isolation receiver, which is electrically connected to the secondary coupling unit, demodulates, regenerates, and eliminates jitter in the second frequency electrical signal, generates a first level signal with the voltage of the first ground line GND3 as a reference, and outputs it. The isolation receiver includes: The second frequency electrical signal is demodulated to obtain a baseband signal demodulator; A low-pass filter electrically connected to the output of the demodulator filters the baseband signal and outputs the original logic signal containing jitter. A clock data recovery circuit electrically connected to the output of the low-pass filter generates a clean clock signal based on the original logic signal. The data regeneration and buffer, which is electrically connected to the output of the clock data recovery circuit, clears the timing jitter in the original logic signal according to the pure clock signal and outputs a first level signal.

[0025] In this embodiment, the first integrated isolation circuit U3 receives a differential PCM data stream signal from the rocket's front-end data acquisition unit with reference to the voltage of the third ground wire GND5. While achieving high-level electrical isolation, it completes signal conditioning, noise suppression, and timing jitter elimination, and outputs a clean and stable first-level signal with reference to the voltage of the first ground wire GND3 for subsequent circuit processing. This solves the problems of ground loop interference, common-mode noise, and signal attenuation over long distances in the rocket telemetry system.

[0026] The differential receiver converts the input differential PCM signal into a single-ended digital signal with GND5 as ground, improving the signal's immunity to common-mode noise and completing the initial signal standardization and noise suppression. The isolation transmitter modulates the low-frequency (baseband) single-ended digital signal onto a higher-frequency first-frequency electrical signal, driving the primary coupling unit (the primary coil in the miniature transformer) to convert the high-frequency first-frequency electrical signal into an alternating magnetic field signal, which then passes through the insulation barrier via the magnetic field. The secondary coupling unit senses the alternating magnetic field signal on the other side of the isolation barrier and reconstructs it, restoring it to a second-frequency electrical signal. The isolation receiver accurately recovers the original digital logic signal from the second-frequency electrical signal, while eliminating all timing defects introduced during transmission and isolation, and outputs a first-level signal.

[0027] The isolated receiver performs carrier stripping through an internally integrated demodulator, demodulating the input second-frequency electrical signal, stripping away the high-frequency carrier, and restoring the baseband signal. A low-pass filter performs noise filtering, removing residual high-frequency harmonic components of the carrier and random noise within the wide bandwidth, smoothing the signal waveform, and outputting the original logic signal. At this point, the original logic signal still exhibits timing jitter, and the logic level does not reach the standard digital level. A clock data recovery circuit performs clock extraction, analyzing the transition edges of the original logic signal to extract a pure clock signal that is strictly synchronized with the transmitting end's data clock frequency and phase. This pure clock signal is a stable, steep-edge square wave clock signal. Data regeneration and buffering perform jitter removal and waveform reconstruction, using the pure clock signal as a precise sampling clock. The original logic signal is sampled and decided at the center of each clock cycle (the moment when the data is most stable), thereby completely eliminating all accumulated jitter in the original logic signal and outputting a first-level signal. This first-level signal is a regenerated signal with steep edges, no jitter, standard logic level, and can be directly used for digital processing.

[0028] like Figure 2 As shown, in an optional embodiment of the present invention, the buffer circuit includes: A Schmitt trigger receives a first-level signal, performs a hysteresis comparison on the input voltage, and outputs a digital signal. The output drive stage, which is electrically connected to the Schmitt trigger, amplifies the received digital signal and outputs a second-level signal.

[0029] In this embodiment, the buffer circuit is mainly used for signal purification, waveform shaping and driving capability enhancement. It converts the first level signal into a second level signal with clear edges, well-defined logic and current driving capability. It eliminates noise and glitches, shapes slow edges and restores standard logic levels through Schmitt triggers, enhances the load-carrying capacity of the signal through the output driver stage, and amplifies the current so that the second level signal can have sufficient power to drive the subsequent back-end regenerative drive circuit 13.

[0030] The multiple differential bus input pins A of the buffer circuit are connected to the data input pin RXD of the first integrated isolation circuit U3; the multiple differential bus output pins Y are respectively connected to the data output pins TXD of the multiple second integrated isolation circuits U2 in the back-end regenerative drive unit; the power input pin VCC is connected to the target voltage output by the power supply unit 14; the ground pin GND is connected to the first ground line GND3; wherein, the number of the differential bus input pins A and the number of the differential bus output pins Y are the same; a nineteenth capacitor C19 is connected in parallel between the power input pin VCC and the ground pin GND.

[0031] like Figure 3 As shown, in an optional embodiment of the present invention, the back-end regeneration drive circuit 13 includes at least one set, and each set of the back-end regeneration drive circuit 13 includes: A second integrated isolation circuit U2 and a second protection circuit U4; The second integrated isolation circuit U2 amplifies and shapes the second level signal, and outputs the PCM data stream signal after passing through a set of bias resistors; the second protection circuit U4, which is electrically connected to the second integrated isolation circuit U2, resists electrostatic discharge at the output of the second integrated isolation circuit U2; the set of bias resistors includes a first resistor R1 and a second resistor R2.

[0032] In this embodiment, the back-end regenerative drive circuit 13 has at least one set, each set including a second integrated isolation circuit U2 and a second protection circuit U4; the circuit structure of the second integrated isolation circuit U2 and the second protection circuit U4 can be the same as the circuit structure of the first integrated isolation circuit U3 and the first protection circuit U6. The differential output terminal of the second integrated isolation circuit U2 amplifies and shapes the second level signal through the first resistor R1 and the second resistor R2, and outputs the PCM data stream signal. The second protection circuit U4 is connected to the two differential output lines and can resist external electrostatic surge impacts to prevent environmental damage to the internal circuit.

[0033] The target voltage is isolated and connected to the power input pin VCC and the enable pin of the second integrated isolation circuit U2 respectively. The first ground pin GND1 of the second integrated isolation circuit U2 is connected to the first ground line GND3. A third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6 are connected in parallel between the power input pin VCC and the first ground pin GND1. The video signal transceiver terminal of the second integrated isolation circuit U2 is connected to the second ground line GND4. The second ground pin GND2 of the second integrated isolation circuit U2 is also connected to the second ground line GND4. A seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9 and a tenth capacitor C10 are connected in parallel between the video signal transceiver terminal pin and the second ground pin GND2. The data output pin TXD of the second integrated isolation circuit U2 is connected to the output terminal of the signal conditioning unit; The second integrated isolation circuit U2 includes a video signal input pin VISIN and a video signal output pin VISOUT; the second integrated isolation circuit U2 includes a driver enable pin DE and a receiver enable pin RE; and the ground pin GND of the second protection circuit U4 is connected to the second ground line GND4.

[0034] In an optional embodiment of this utility model, the second integrated isolation circuit U2 includes: The input buffer and level converter receives the second level signal, converts the second level signal into a preset operating voltage, provides preliminary noise margin, and outputs a standard second level signal. An isolation regeneration engine, electrically connected to the input buffer and level converter, performs electrical isolation, timing jitter elimination, and waveform regeneration on the standard second-level signal, and outputs an enhanced second-level signal. The differential driver, which is electrically connected to the isolated regeneration engine, receives the enhanced second-level signal, amplifies the enhanced second-level signal, and outputs the PCM data stream signal.

[0035] In this embodiment, the input buffer and level converter are used to directly receive the second level signal from the signal conditioning unit, realizing secure signal access, level domain conversion and preliminary shaping, and outputting a standard second level signal with the voltage of the third ground line GND5 as a reference; the isolation regeneration engine is electrically connected to the output terminal of the input buffer and level converter, receives the standard second level signal, realizes electrical isolation and signal quality regeneration, and outputs an enhanced second level signal with accurate timing, clear logic and complete electrical isolation; the differential driver performs power amplification and differential conversion on the enhanced second level signal, thereby ensuring that the signal can drive the subsequent long-distance cable load.

[0036] like Figure 4 and Figure 5 As shown, in an optional embodiment of the present invention, the relay circuit for the wired pulse code modulation signal further includes: The power supply unit 14 includes a power isolation module U1. The input terminal of the power isolation module U1 is connected to an external 12V DC power supply, and the output terminal provides multiple isolated target voltages, which are respectively connected to the power input terminals of the isolation drive circuit 11, the signal conditioning circuit 12, and the back-end regeneration drive circuit 13.

[0037] In this embodiment, the power supply unit 14 converts the external DC power supply into a multi-channel isolated target voltage through the power isolation module U1. For example, the target voltage can be set to 3.3V or 5V for isolated power supply of the relay circuit.

[0038] The positive voltage input pin +VIN and negative voltage input pin of the power isolation module U1 A second capacitor C2 is connected between VIN and the positive voltage output pin +VOUT and negative voltage output pin of the power isolation module U1. A first capacitor C1 is connected between VOUT and the positive voltage output pin +VOUT, which outputs the target voltage. The negative voltage output pin... VOUT is connected to the first ground wire GND3.

[0039] In an optional embodiment of this utility model, the rocket telemetry system includes: The relay circuit, front-end data acquisition unit, and back-end data processor of the wired pulse code modulation signal; The relay circuit is connected between the front-end data acquisition unit and the back-end data processor of the rocket telemetry system. It isolates, shapes, and amplifies the PCM data stream signal generated by the front-end data acquisition unit, and transmits the regenerated PCM data stream signal to the back-end data processor.

[0040] In this embodiment, the rocket telemetry system includes a front-end data acquisition unit, a wired pulse code modulation (PCM) signal relay circuit, and a back-end data processing unit. These three components are sequentially connected via a cable network, forming a complete data acquisition, relay, and processing link. The front-end data acquisition unit primarily acquires various physical parameters in real time using sensors. The wired PCM signal relay circuit pulse-codes and modulates the acquired parameters and transmits them. The back-end data processing unit receives the PCM data stream delivered through the transmission link and reconstructs the original measurement data from each sensor for use in subsequent stages.

[0041] This invention effectively cuts off the ground loop, suppresses common-mode interference of up to several hundred volts, thereby protecting front-end and back-end equipment, improving system robustness, greatly reducing the bit error rate, and realizing reliable long-distance relay of high-speed PCM signals in complex environments.

[0042] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A relay circuit for wired pulse code modulation signals, characterized in that, The circuit is used in the rocket telemetry system and includes: An isolated drive circuit (11) electrically connected to the rocket telemetry system. Signal conditioning circuit (12) electrically connected to the isolation drive circuit (11); The back-end regeneration drive circuit (13) is electrically connected to the signal conditioning circuit (12). The wired pulse code modulation (PCM) data stream signal output by the rocket telemetry system is input to the isolation drive circuit (11). The isolation drive circuit (11) performs isolation differential conversion processing on the PCM data stream signal and outputs a first level signal. The first level signal is input to the signal conditioning circuit (12). The signal conditioning circuit (12) performs differential buffering and shaping processing on the first level signal and outputs a second level signal. The second level signal is input to the back-end regeneration drive circuit (13). The back-end regeneration drive circuit (13) performs power amplification and waveform shaping on the second level signal and outputs the PCM data stream signal.

2. A repeater circuit for a wire pulse code modulation signal according to claim 1, characterized in that, The isolation drive circuit (11) includes: The first integrated isolation circuit (U3) receives the input PCM data stream signal through the third resistor (R3); the resistance value of the third resistor (R3) is equal to the characteristic impedance of the cable. A first protection circuit (U6) is connected to the differential receiving end of the first integrated isolation circuit (U3), and the other end of the first protection circuit (U6) is connected to the third ground line (GND5). The third resistor (R3) is connected in parallel on the two differential input lines of the differential receiver of the first integrated isolation circuit (U3); the first protection circuit (U6) filters out spike signals in the PCM data stream signal; the first integrated isolation circuit (U3) receives the PCM data stream signal and performs electrical isolation, and outputs a first level signal.

3. The relay circuit for wired pulse code modulation signals according to claim 2, characterized in that, The first integrated isolation circuit (U3) includes: The differential receiver converts the input PCM data stream signal into a single-ended logic signal with reference to the voltage of the third ground line (GND5); An isolated transmitter electrically connected to the output of the differential receiver modulates the single-ended logic signal into a first frequency electrical signal and drives a primary coupling unit electrically connected to the output of the isolated transmitter to convert the first frequency electrical signal into an alternating magnetic field signal. The secondary coupling unit, which is physically coupled to the primary coupling unit, senses the corresponding alternating magnetic field signal and converts it into a second frequency electrical signal. The isolation receiver, which is electrically connected to the secondary coupling unit, demodulates, regenerates, and eliminates jitter in the second frequency electrical signal, generates a first level signal with the voltage of the first ground line (GND3) as a reference, and outputs it.

4. The relay circuit for wired pulse code modulation signals according to claim 3, characterized in that, The isolation receiver includes: The second frequency electrical signal is demodulated to obtain a baseband signal demodulator; A low-pass filter electrically connected to the output of the demodulator filters the baseband signal and outputs the original logic signal containing jitter. A clock data recovery circuit electrically connected to the output of the low-pass filter generates a clean clock signal based on the original logic signal. The data regeneration and buffer, which is electrically connected to the output of the clock data recovery circuit, clears the timing jitter in the original logic signal according to the pure clock signal and outputs a first level signal.

5. The relay circuit for wired pulse code modulation signals according to claim 1, characterized in that, The signal conditioning circuit (12) includes a buffer circuit (U5), which includes: A Schmitt trigger receives a first-level signal, performs a hysteresis comparison on the input voltage, and outputs a digital signal. The output drive stage, which is electrically connected to the Schmitt trigger, amplifies the received digital signal and outputs a second-level signal.

6. The relay circuit for wired pulse code modulation signals according to claim 1, characterized in that, The back-end regeneration drive circuit (13) includes at least one set, and each set of the back-end regeneration drive circuit (13) includes: A second integrated isolation circuit (U2) and a second protection circuit (U4); The second integrated isolation circuit (U2) amplifies and shapes the second level signal, and outputs the PCM data stream signal through a set of bias resistors; the second protection circuit (U4), which is electrically connected to the second integrated isolation circuit (U2), resists electrostatic shock at the output terminal of the second integrated isolation circuit (U2); the set of bias resistors includes a first resistor (R1) and a second resistor (R2).

7. The relay circuit for wired pulse code modulation signals according to claim 6, characterized in that, The second integrated isolation circuit (U2) includes: The input buffer and level converter receives the second level signal, converts the second level signal into a preset operating voltage, provides preliminary noise margin, and outputs a standard second level signal. An isolation regeneration engine, electrically connected to the input buffer and level converter, performs electrical isolation, timing jitter elimination, and waveform regeneration on the standard second-level signal, and outputs an enhanced second-level signal. The differential driver, which is electrically connected to the isolated regeneration engine, receives the enhanced second-level signal, amplifies the enhanced second-level signal, and outputs the PCM data stream signal.

8. The relay circuit for wired pulse code modulation signals according to claim 1, characterized in that, Also includes: The power supply unit (14) includes a power isolation module (U1). The input terminal of the power isolation module (U1) is connected to an external 12V DC power supply, and the output terminal provides multiple isolated target voltages, which are respectively connected to the power input terminals of the isolation drive circuit (11), the signal conditioning circuit (12), and the back-end regeneration drive circuit (13).

9. A rocket telemetry system, characterized in that, include: The relay circuit, front-end data acquisition unit, and back-end data processor for wired pulse code modulation signals as described in any one of claims 1 to 8; The relay circuit is connected between the front-end data acquisition unit and the back-end data processor of the rocket telemetry system. It isolates, shapes, and amplifies the PCM data stream signal generated by the front-end data acquisition unit, and transmits the regenerated PCM data stream signal to the back-end data processor.

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