CN218866000U

CN218866000U - Pulse signal voltage standing-wave ratio testing device

Info

Publication number: CN218866000U
Application number: CN202222886841.XU
Authority: CN
Inventors: 张虹
Original assignee: Nanjing Enruite Industrial Co Ltd
Current assignee: Nanjing Enruite Industrial Co Ltd
Priority date: 2022-10-31
Filing date: 2022-10-31
Publication date: 2023-04-14
Anticipated expiration: 2032-10-31

Abstract

The utility model discloses a pulse signal voltage standing wave ratio testing device, which comprises a double directional coupler, a wave detector, an amplitude limiter, an A/D converter, a main controller and a double-port RAM memory; the dual-directional coupler is respectively connected with the first detector and the second detector, and the first detector is connected with a first input port of the dual-port RAM through the first A/D converter; the second detector is connected with a second input port of the double-port RAM memory through the amplitude limiter and the second A/D converter; the output port of the dual-port RAM memory is connected with the main controller, and the main controller is used for calculating and displaying the voltage standing wave ratio. The utility model discloses a pulse signal voltage standing-wave ratio testing arrangement is applicable to high frequency signal transmission nodes such as two transmitter output ends, high frequency rotation interlinkage, feeder port, antenna port, matching network port, cable adapter of secondary radar, has universal suitability.

Description

Pulse signal voltage standing-wave ratio testing device

Technical Field

The utility model relates to a signal acquisition, AD conversion and demonstration technical field, concretely relates to pulse signal voltage standing wave ratio testing arrangement.

Background

The transmission efficiency of high-frequency signals is closely related to the states of all parts and connection points in the transmission line, and in order to ensure effective transmission of the high-frequency signals, reduce signal loss in transmission and avoid signal reflection to cause local heating of the transmission line and influence the stability and reliability of a system, the voltage standing-wave ratio of important nodes in the high-frequency transmission line needs to be monitored, problems are found in time, and the system is maintained in time.

The amplitude of the high-frequency signal fluctuates in the transmission line, the voltage standing wave ratio is the ratio of the maximum voltage value and the minimum voltage value of the high-frequency signal on the transmission line, wherein the maximum voltage value is obtained by adding the amplitudes of the forward wave signal and the backward wave signal, and the minimum voltage value is obtained by subtracting the amplitudes of the forward wave signal and the backward wave signal. The forward wave is the signal amplitude in the direction of signal transmission and the backward wave is the signal amplitude in the direction of signal reflection. Ideally, the impedance of the transmission line is completely matched, the high-frequency signal is transmitted forward without loss, no reflection is generated, the amplitude of the backward wave signal is zero, and the voltage standing wave ratio is 1. In practical situations, the transmission line has various components and connectors, impedance complete matching cannot be achieved, each node has voltage standing wave ratio index requirements in use, and the standing wave ratio requirements are not more than 1.2 at more important nodes such as high-frequency rotation cross connection; the standing wave ratio requirement at the output port of the transmitter or the antenna port is not more than 1.5. When the standing-wave ratio is larger than 1.5, the conditions of matching load open circuit, cable disconnection or cable adapter loosening can occur, and the maintenance and the repair are required to be carried out immediately. Therefore, a standing-wave ratio testing device which is simple in structure, convenient to operate and sensitive in response is needed.

SUMMERY OF THE UTILITY MODEL

In order to solve the above problems, the utility model provides a pulse signal voltage standing wave ratio testing device, which comprises a dual directional coupler, a wave detector, an amplitude limiter, an A/D converter, a main controller and a dual-port RAM memory; the dual-directional coupler is respectively connected with the first detector and the second detector, and the first detector is connected with a first input port of the dual-port RAM through the first A/D converter; the second detector is connected with a second input port of the double-port RAM memory through the amplitude limiter and the second A/D converter; the output port of the double-port RAM memory is connected with a main controller, and the main controller is used for calculating and displaying the voltage standing wave ratio; the signal to be tested is a pulse signal.

Furthermore, the dual directional coupler comprises a first microstrip line, a second microstrip line, a third microstrip line, a first resistor and a second resistor, wherein a first port and a second port are respectively arranged at two ends of the first microstrip line; one end of the second microstrip line is a third port, and the other end of the second microstrip line is grounded after being connected with the first resistor in series; one end of the third microstrip line is a fourth port, and the other end of the third microstrip line is grounded after being connected with the second resistor in series.

Further, a signal to be tested is input from the first port and output from the second port; the first microstrip line is a main transmission line and can bear the peak power and the average power of a signal to be tested; the second microstrip line is parallel to the first microstrip line, the distance between the second microstrip line and the first microstrip line is a first interval, and the forward wave signal is coupled and output from the third port by a first coupling degree; the third microstrip line is parallel to the first microstrip line, the distance between the third microstrip line and the first microstrip line is a second interval, and the backward wave signal is coupled and output from the fourth port by a second degree of coupling; the first distance is larger than the first distance, and the first coupling degree is smaller than the second coupling degree.

Furthermore, the first port, the second port, the third port and the fourth port are coaxial sockets with grounded shells and are respectively connected with corresponding coaxial cables, wherein the third port and the fourth port are respectively connected with the first detector and the second detector through the coaxial cables, and the shells of the dual directional couplers are grounded.

Furthermore, the reference voltages of the first A/D converter and the second A/D converter are the same, and the forward wave coupling degree of the double directional coupler is smaller than the backward wave coupling degree.

Furthermore, the output end of the first detector is connected with the input end of the first A/D converter, the output end of the second detector is connected with the input end of the second A/D converter after passing through the amplitude limiter, and the amplitude limiting voltage of the amplitude limiter is equal to the reference voltage of the second A/D converter.

Further, the A/D conversion clocks of the first and second A/D converters lag behind the sampling clock by half a cycle.

Compared with the prior art, the utility model discloses following beneficial effect has:

the pulse signal voltage standing-wave ratio testing device has the advantages of simple structure, easy operation, high testing efficiency and low testing cost; when the backward wave is detected, an amplitude limiter is added between the wave detector and the A/D converter, so that the conversion precision of the backward wave is improved; the method is suitable for high-frequency signal transmission nodes such as two transmitter output ends of a secondary radar, a high-frequency rotary cross connection, a feeder port, an antenna port, a matching network port, a cable adapter and the like, and has universal applicability.

Drawings

Fig. 1 is a schematic diagram illustrating a pulse signal voltage standing wave ratio testing apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic signal processing diagram of a pulse signal voltage standing wave ratio testing apparatus according to an embodiment of the invention.

Fig. 3 is a schematic structural diagram of a dual directional coupler according to an embodiment of the invention.

Fig. 4 is a schematic diagram of sampling secondary radar transmission signals according to an embodiment of the present invention.

Description of the reference numerals:

the device comprises a first port 1, a first microstrip line 2, a second port 3, a second microstrip line 4, a first resistor 5, a third port 6, a third microstrip line 7, a second resistor 8 and a fourth port 9.

Detailed Description

The pulse signal voltage standing wave ratio testing device provided by the invention is described in detail below with reference to the accompanying drawings.

The utility model relates to a pulse signal voltage standing wave ratio testing arrangement specifically includes following several parts: the system comprises a double directional coupler, a detector, an amplitude limiter, an A/D converter, a main controller and a double-port RAM memory; the dual-directional coupler is respectively connected with the first detector and the second detector, and the first detector is connected with a first input port of the dual-port RAM through the first A/D converter; the second detector is connected with a second input port of the double-port RAM memory through the amplitude limiter and the second A/D converter; the output port of the double-port RAM memory is connected with the main controller. The main controller is used for calculating and displaying the voltage standing wave ratio; the signal to be tested is a pulse signal.

The double directional coupler: including forward wave signal coupling and backward wave signal coupling. And disconnecting the high-frequency pulse signal transmission line at a monitoring point, connecting a double directional coupler in series, and coupling a few forward wave signals and backward wave signals from the main transmission line, wherein the double directional coupler needs to be designed according to the peak power and the average power of the high-frequency signals and the reference voltage of the A/D converter. Therefore, the dual directional coupler needs to meet certain index requirements: firstly, a main transmission path of the bi-directional coupler can bear the peak power and the average power of a transmission signal, so that the overheating problem is avoided; secondly, the forward wave coupling degree of the double-directional coupler needs to be designed according to the peak power and the average power of the high-frequency signal and the reference voltage of the A/D converter, and the forward wave coupling signal is as close to the reference voltage value as possible under the condition of meeting the reference voltage of the A/D converter so as to obtain the A/D conversion precision as high as possible; furthermore, the backward wave coupling degree of the dual directional coupler is designed by considering: when the standing wave ratio is 2.0, the backward wave coupling signal is close to but not more than the reference voltage of the A/D converter, so that linear A/D conversion output can be obtained under the condition that the standing wave ratio is not more than 2.0, the standing wave ratio 1.5 is a threshold point for fault judgment, and the fault of the transmission line can be judged as long as the standing wave ratio is more than 1.5, so that when the standing wave reaches or exceeds 2.0, the specific exceeding amount is not required to be concerned, and the fault of the transmission line is definitely judged; and finally, according to the characteristic that the amplitude of the transmitted signal is greater than that of the reflected signal, because the forward wave and the backward wave adopt the same A/D converter and have the same reference voltage, the coupling degree of the forward wave is smaller than that of the backward wave, and the maximum amplitude of the forward wave and the backward wave coupling signal is ensured to be equivalent.

The main transmission path of the bi-directional coupler is capable of bearing the peak power and the average power of the transmission signal, and the insertion loss of the main transmission path of the bi-directional coupler is reduced as much as possible.

The coupling degree of the double directional coupler needs to be designed according to the magnitude of the peak power of a transmission signal and the reference voltage of an A/D converter, and according to the principle that a reflection signal is generated by a transmission signal and is smaller than the transmission signal, if a first A/D converter and a second A/D converter with the same reference voltage are adopted for a forward wave signal and a backward wave signal, the coupling degree of the forward wave is smaller than the coupling degree of the backward wave, and the coupling output of the forward wave is equal to the coupling output of the backward wave; if the first a/D converter with a larger reference voltage is used for the forward wave signal and the second a/D converter with a smaller reference voltage is used for the backward wave signal, the forward wave coupling degree and the backward wave coupling degree may be the same. The value of the coupling degree is to ensure that the maximum A/D conversion precision is obtained, namely the maximum voltage of the signal to be converted is close to but not more than the reference voltage of the A/D converter.

An amplitude limiter: the output end of the backward wave detector is connected with an amplitude limiter, so that the backward wave coupling signal input to the A/D converter does not exceed the reference voltage of the A/D converter when the standing-wave ratio is more than 2.0, and the conversion precision of the backward wave is improved.

An A/D converter: and the forward wave and backward wave signal processing module is used for receiving and processing the forward wave and backward wave signals to obtain digitized forward wave and backward wave voltage amplitude values. For the pulse modulation signal, detection is needed firstly, and then the digital pulse modulation signal voltage amplitude value is obtained through sampling and A/D conversion on the detected pulse signal, wherein the sampling rate is not less than 2 times of the reciprocal of the pulse width.

A detector: and processing the forward wave and the backward wave of the pulse signal output by the double directional coupler to obtain the envelope of the pulse signal.

An A/D converter: modulating a pulse gating sampling clock and an A/D conversion clock, and respectively sampling and A/D converting an envelope in a pulse by a detector and an A/D converter to finally obtain a quantized value of the envelope of the pulse signal, wherein the frequency of the sampling clock is more than 2 times of the bandwidth of the envelope signal, and the A/D conversion clock lags behind the sampling clock by half a period, so that the A/D conversion is carried out after the sampling signal is stably kept, and the specific reference can be made to figure 4.

Dual port RAM memory: the sampling rate and A/D conversion rate of forward wave and backward wave are very high, if real-time data transmission is carried out between the main controller, the processing time of a computer can be greatly occupied, the standing wave ratio calculation and display are only 1 item in the numerous state display of radar, the data transmission efficiency can be effectively improved by carrying out stage data transmission through the memory, the quantized values of the pulse signal envelopes of the forward wave and the backward wave are sequentially written into a double-port RAM, the main controller reads all the forward wave and backward wave values stored in the double-port RAM at one time according to the refreshing rate of the voltage standing wave ratio, the counter and the writing pointer of the double-port RAM are reset after data is read, the forward wave and backward wave values after each reading operation are written from the head, the refreshing rate is a fixed value, and a double-port RAM area with a proper size can be set according to the sampling times in each refreshing interval.

A master controller: the main controller restores the real voltage amplitude values of the forward wave and the backward wave according to the forward wave coupling degree and the backward wave coupling degree of the used dual directional coupler, and calculates the voltage standing wave ratio. The main controller is a single chip microcomputer or a computer, and the main controller in the embodiment is preferably the computer. The voltage standing wave ratio obtained in real time usually fluctuates in a certain range, if the voltage standing wave ratio is refreshed and displayed directly according to the A/D conversion rate, the numerical value changes quickly and is inconvenient for human eyes to observe, according to the response time of human eyes, the voltage standing wave ratio is refreshed and displayed in a fixed period, and the displayed numerical value is the average value of a plurality of voltage standing wave ratios in the refreshing period.

To facilitate understanding of the public, embodiments of the present invention will be described in further detail below, taking the secondary radar transmitter output as an example.

The secondary radar has two transmitters of Σ and Ω, which respectively generate a pulse-modulated Σ transmission signal and an Ω transmission signal, and the envelope of the pulse signal is as shown in fig. 4, where the Σ transmission signal includes two pulses P1 and P3, the Ω transmission signal includes 1 pulse P2, and the pulse widths are all 0.8 μ s. The peak power of both transmission signals is more than 1.5kW, and the corresponding peak voltage is more than 274V. By taking the standing wave ratio of 1.5, the voltage of the obtained forward wave is 5 times of that of the backward wave, and the voltage is 274V and 54.8V respectively.

The sigma-delta transmitter of the secondary radar generates a pulse modulated sigma-delta transmission signal, the envelope of which is shown in fig. 4, wherein the sigma-delta transmission signal comprises two pulses P1 and P3, and the pulse width is 0.8 μ s. The pulse power of the transmission signals is larger than 1.5kW, and the corresponding peak voltage is larger than 274V. In order to simplify the circuit structure, the same A/D converter is adopted for forward wave voltage and backward wave coupling voltage, the reference voltage of the A/D converter is 2V, and the forward wave voltage 274V is attenuated to 2V through-43 dB; when the standing-wave ratio is 1.5, the backward wave voltage is 54.8V, and is attenuated to 2V through-29 dB; when the standing-wave ratio is 2.0, the backward wave voltage is 91.3V, and is attenuated to 2V through-33 dB. The design of the bi-directional coupler is as follows: the redundancy of 3dB attenuation is added to the coupling degree of the forward wave, and the voltage after the coupling of the forward wave is ensured not to exceed the reference voltage 2V of the A/D converter, namely the coupling degree of the forward wave is-46 dB; the coupling degree of backward wave is-33 dB, so that the voltage of the coupled backward wave is not more than 2V when the standing-wave ratio of the backward wave is not more than 2.0, and the A/D conversion is in a linear range; the standing-wave ratio exceeds 1.5 and is in a fault state, so the standing-wave ratio exceeds 2.0 or more, linear conversion has no practical significance, and the linear conversion is directly displayed for 2.0, so that an amplitude limiter with the amplitude of 2V is added at the output end of a backward wave detector, the output end of the amplitude limiter is connected with an A/D converter, and the voltage of an A/D input end does not exceed 2V when the standing-wave ratio is more than 2.0.

A dual directional coupler for realizing the coupling output of forward wave and backward wave signals is shown in fig. 3, and the dual directional coupler includes a first microstrip line 2, a second microstrip line 4, a third microstrip line 7, a first resistor 5 and a second resistor 8, where two ends of the first microstrip line 2 are respectively a first port 1 and a second port 3; one end of the second microstrip line 4 is a third port 6, and the other end is grounded after being connected with the first resistor 5 in series; one end of the third microstrip line 7 is a fourth port 9, and the other end is grounded after being connected in series with the second resistor 8. A signal to be tested is input from a first port 1 and output from a second port 3; the first microstrip line 2 is a main transmission line and can bear 1.5kW peak power and 7.5W average power; the second microstrip line 4 is parallel to the first microstrip line 2, the distance between the second microstrip line and the first microstrip line is a first distance, and a forward wave signal is coupled and output from an output port of the second microstrip line 4 by a first coupling degree; the third microstrip line 7 is parallel to the first microstrip line 2, the distance between the third microstrip line and the first microstrip line is a second distance, and a backward wave signal is coupled and output from the fourth port 9 by a second coupling degree; the first distance is larger than the first distance, and the first coupling degree is smaller than the second coupling degree; in this embodiment, the first coupling is-46 dB and the second coupling is-33 dB. The first port 1 and the second port 3, the third port 6 and the fourth port 9 are coaxial sockets with grounded shells and are respectively connected with corresponding coaxial cables, wherein the third port 6 and the fourth port 9 are respectively connected with the first detector and the second detector through the coaxial cables, and the shells of the double directional couplers are grounded.

The specific test device is shown in fig. 1, the sampling process is shown in fig. 4, and since the pulse widths of the secondary radar sigma-delta transmission signal and the omega transmission signal are both 0.8 μ s, the sampling clocks are both 5MHz, which is greater than 2/0.8 μ s =2.5MHz. The inherent modulation pulse of a secondary radar system is utilized, the modulation pulse is delayed by 0.1 mu s, the pulse width of 0.6 mu s is intercepted to generate a sampling gating signal, the sampling gating signal controls a sampling clock, the sampling clock outputs only in the effective period of the gating signal, the sampling clock samples the pulse envelope, and the sampling pulse is delayed by 0.1 mu s to generate an A/D conversion clock. And obtaining a quantized value by A/D conversion of the sampled forward wave and backward wave coupling signals.

The transmitting period of the secondary radar is 250Hz, each time of transmission generates 6 forward wave and backward wave numbers, 1500 groups of data per second are written into the double-port RAM in sequence and counted; the computer reads corresponding forward wave and backward wave values from the dual-port RAM at one time according to the written count value according to the refresh rate of one frame per second, and resets the count value and the write pointer of the dual-port RAM after the computer reads the data, so that the writing of the forward wave and the backward wave starts from the beginning. Since the refresh rate is a fixed value, the size of the dual-port RAM memory area is also fixed, and the dual-port RAM memory area is set to 2000 sets of forward wave and backward wave memory cells in consideration of a certain redundancy. The computer restores the real voltage amplitude values of the forward wave and the backward wave according to the-46 dB forward wave coupling degree and the-33 dB backward wave coupling degree, calculates the voltage standing wave ratio value corresponding to each sampling and calculates the average value in the refreshing rate period, and refreshes the display value of the voltage standing wave ratio by using the average value. The refresh rate is set to 1 second, i.e. the voltage standing wave ratio is updated every 1 second, depending on the human eye reaction time. The calculation flow is as shown in fig. 2, and the detector, limiter, and the like are omitted in fig. 2.

The utility model discloses although the embodiment of device uses two transmitter output ends of secondary radar as an example, high frequency signal transmission nodes such as high-frequency rotation interlinkage, feeder port, antenna port, matching network port, cable adapter of secondary radar are suitable for this device equally.

The beneficial effects of the utility model are summarized as follows:

the pulse signal voltage standing-wave ratio testing device has the advantages of simple structure, easy operation, high testing efficiency and low testing cost; when the backward wave is detected, an amplitude limiter is added between the wave detector and the A/D converter, so that the conversion precision of the backward wave is improved; the utility model is suitable for a high frequency signal transmission nodes such as two transmitter output ends, the rotatory handing-over of high frequency, feeder port, antenna port, matching network port, cable adapter of secondary radar have universal suitability.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A pulse signal voltage standing wave ratio testing device is characterized by comprising a double directional coupler, a wave detector, an amplitude limiter, an A/D converter, a main controller and a double-port RAM memory; the dual-directional coupler is respectively connected with the first detector and the second detector, and the first detector is connected with a first input port of the dual-port RAM through the first A/D converter; the second detector is connected with a second input port of the double-port RAM memory through the amplitude limiter and the second A/D converter; the output port of the double-port RAM memory is connected with a main controller, and the main controller is used for calculating and displaying the voltage standing wave ratio; the signal to be tested is a pulse signal.

2. The device for testing the voltage standing-wave ratio of the pulse signal according to claim 1, wherein the dual directional coupler comprises a first microstrip line (2), a second microstrip line (4), a third microstrip line (7), a first resistor (5) and a second resistor (8), and a first port (1) and a second port (3) are respectively arranged at two ends of the first microstrip line (2); one end of the second microstrip line (4) is a third port (6), and the other end of the second microstrip line is grounded after being connected with the first resistor (5) in series; one end of the third microstrip line (7) is a fourth port (9), and the other end is grounded after being connected with the second resistor (8) in series.

3. The pulse signal voltage standing wave ratio test device according to claim 2, wherein the signal to be tested is input from the first port (1) and output from the second port (3); the first microstrip line (2) is a main transmission line and can bear the peak power and the average power of a signal to be tested; the second microstrip line (4) is parallel to the first microstrip line (2), the distance between the second microstrip line and the first microstrip line is a first distance, and a forward wave signal is coupled and output from the third port (6) by a first coupling degree; the third microstrip line (7) is parallel to the first microstrip line (2), the distance between the third microstrip line and the first microstrip line is a second distance, and a backward wave signal is coupled and output from the fourth port (9) by a second coupling degree; the first distance is larger than the first distance, and the first coupling degree is smaller than the second coupling degree.

4. The testing apparatus for voltage standing wave ratio of pulse signals according to claim 3, wherein the first port (1), the second port (3), the third port (6) and the fourth port (9) are coaxial sockets with grounded housings, and are respectively connected to corresponding coaxial cables, wherein the third port (6) and the fourth port (9) are respectively connected to the first detector and the second detector through the coaxial cables, and the housings of the dual directional couplers are grounded.

5. The apparatus according to claim 4, wherein the first and second A/D converters have the same reference voltage, and the degree of forward wave coupling of the bi-directional coupler is smaller than the degree of backward wave coupling.

6. The apparatus according to claim 5, wherein the output of the first detector is connected to the input of the first A/D converter, the output of the second detector is connected to the input of the second A/D converter after passing through a limiter, and the limiting voltage of the limiter is equal to the reference voltage of the second A/D converter.

7. The device according to claim 4, wherein the A/D conversion clocks of the first and second A/D converters lag behind the sampling clock by half a cycle.