System and method for measuring actuation time of microwave multi-channel delay assembly

Abstract

A system and a method for measuring actuation time of a microwave multichannel time delay assembly belong to the field of time delay measurement of measurement and control, communication and the like, and the system comprises a microwave signal source, a power divider, a measured microwave multichannel time delay assembly, a combiner, a detector, an oscilloscope and an instruction sending device which are connected with one another. And connecting the system, starting the microwave signal source, continuously sending an instruction sequence by the instruction sending device, changing the time delay of the channel, changing the time interval of the instruction in the instruction sequence, and observing the waveform on the oscilloscope until the waveform does not change before and after the change of the time interval, thereby obtaining the action time of the microwave multi-channel time delay assembly. According to the method, a conventional laboratory instrument is adopted to build a measurement system, the action time of the microwave multi-channel time delay assembly to be measured is obtained through simple measurement steps, judgment is carried out only according to an output result after the action of the microwave multi-channel time delay assembly is completed, factors such as cable time delay do not need to be considered, and compared with the prior art, the cost is low, and implementation is convenient.

Description

Technical Field

[0001] This invention belongs to the field of time delay measurement in measurement and control, communication, etc., and specifically relates to the measurement of the action time of microwave multi-channel delay components in phased array antennas. Background Technology

[0002] A phased array antenna is an advanced antenna system that changes the direction, shape, or pointing of a beam by controlling the phase (and sometimes amplitude) of multiple independent radiating elements without physically moving the antenna itself. It is widely used in radar, communications, satellite, and 5G fields.

[0003] A phased array consists of multiple independent antenna elements (such as patch antennas, dipoles, etc., also called array elements or radiating elements) arranged in a regular array (straight line, plane or curved surface). By precisely controlling the phase difference of the transmitted signal of each element, the signals of each element are coherently superimposed in space, forming a strong main beam in a specific direction and canceling each other out in other directions.

[0004] Phased array antennas can achieve rapid beam scanning, with electronic scanning speeds reaching microsecond levels, far faster than mechanical rotation; they have multi-beam capability, simultaneously generating multiple independent beams to perform different tasks (such as simultaneously searching and tracking multiple targets); the failure of individual elements has little impact on overall performance, resulting in high reliability; the beam can rapidly change direction, making it difficult to intercept; and the beam shape can be dynamically adjusted (such as widening, shaping nulls to resist interference), providing flexible beamforming.

[0005] In a phased array antenna, the beam pointing is primarily determined by the phase difference between the array elements. By precisely controlling the phase of the transmitted or received signal of each radiating element, the antenna beam can perform rapid scanning in space without mechanical movement. The antenna beam velocity depends on the rate at which the phase of the array elements changes.

[0006] The command-controlled microwave multi-channel delay component is a component that generates phase differences among the various elements of a phased array antenna. By controlling the delay of each channel, the phase is changed, thereby controlling the beam direction.

[0007] The microwave multi-channel delay component is a module / subsystem that can perform high-precision, programmable time delay control on multiple parallel microwave signal channels. Its core function is to control the "time" of electromagnetic wave propagation, that is, to precisely schedule when each array element transmits a signal.

[0008] Microwave multi-channel delay components are a landmark component in the transition of broadband phased array systems from the "phase-shifting era" to the "true delay era." By precisely controlling the "time axis" of microwave signals, it solves a fundamental problem in broadband signal processing and is a key enabling technology supporting the high performance and multifunctionality of modern radar, communication, and electronic warfare systems.

[0009] In microwave multi-channel delay components, the delay of each channel is controlled by commands. Measuring the action time from receiving the control command to the completion of the final action of each delay channel is a crucial technical indicator with clear engineering significance: this action time parameter directly determines the minimum beam pointing change time interval of the system, thus limiting the maximum beam scanning speed of the system. Beam scanning speed requirements are explicitly included in the core design specifications of many phased array systems.

[0010] In existing technologies, time delay measurement can be achieved using a high-speed real-time oscilloscope combined with pulse alignment. Connection method: Control port: Connect the "latch / enable" signal (LVDS / TTL) to Ch1 of the oscilloscope using an SMA probe; RF port: Connect a coaxial cable to the input and output of the delay component to build a "reference channel" and a "test channel", and input both signals to Ch2 / Ch3 at the same time.

[0011] Steps: 1) The FPGA sends a single "state transition" command (e.g., from 0000 to 1111); 2) The oscilloscope is triggered at the rising edge of Ch1, and the time t0 when the pulse envelopes of Ch2 and Ch3 first "overlap" is recorded; 3) Command-response delay Δt = t0 – t_trigger; 4) Repeatability after multiple averaging is <50 ps.

[0012] This method requires an oscilloscope with a bandwidth of ≥20 GHz (costing more than 500,000 RMB) and a phase-stabilized cable of <0.4 mm; otherwise, cable bending will introduce an error of >30 ps, ​​resulting in high costs and many factors to consider.

[0013] Wan Limai disclosed a similar method in his article "Time Delay Measurement of Modulation Systems Based on Oscilloscope" in the 32nd volume (5th issue) of Foreign Electronic Measurement Technology in 2013.

[0014] Furthermore, Chinese patent CN112260890B, "Digital Array Delay Measurement Method," discloses the following: A reference clock generated by a clock source is sent to a time-frequency system to generate multiple sampling clocks and synchronization signals, which are distributed to delay measurement modules of different subarrays in the digital array system. The phase relationship between the synchronization trigger times of the subarrays is detected by the delay measurement module to obtain the output signals of each channel. The delay measurement module sends the reference signal of the delay measurement point and the two-stage clock of the excitation channel of each subarray to the clock synchronization system FPGA after sampling. The relative delay between multiple channels is measured. The reference signal is processed by frequency difference with different delay times. After frequency difference, the single-frequency signal related to the frequency domain position and delay time is used for delay calculation to obtain the relative delay value between the channel under test and the reference channel, and the delay time is calculated. This method involves a lot of hardware and is inconvenient to implement.

[0015] Currently, there is no effective, low-cost, and rapidly implementable measurement solution. Summary of the Invention

[0016] In view of the shortcomings of current technology, this invention proposes a low-cost measurement scheme using common instruments.

[0017] To achieve the purpose of the invention, the present invention proposes the following technical solution: a microwave multi-channel delay component action time measurement system, characterized in that the system includes a microwave signal source, a microwave N-channel power divider connected to the microwave signal source, the output of the microwave N-channel power divider connected to the microwave multi-channel delay component under test, the output of the microwave multi-channel delay component connected to a microwave N-channel combiner, the output of the microwave N-channel combiner connected to a detector, the output of the detector connected to a pulse time measuring device, and the microwave multi-channel delay component is also connected to a command sending device via a communication interface; the pulse time measuring device is an oscilloscope.

[0018] Furthermore, N≥2.

[0019] Furthermore, the bandwidth of the oscilloscope is ≥20MHz.

[0020] Based on the above measurement system, this invention also proposes a method for measuring the action time of a microwave multi-channel delay component, comprising the following steps: S1: Set up the measurement system; S2: Turn on the microwave signal source and output a sine wave; S3: The command sending device continuously sends a sequence of commands, including command 1 and command 2. Command 1 sets the delay of half of the channels to 0, and the delay of the other half of the channels to a value that creates a 180° phase difference at the test frequency. Command 2 sets the delay of all channels to 0. S4: Change the time interval between instruction 1 and instruction 2, and observe the waveform on the oscilloscope until the waveform before and after the time interval change does not change; S5: Read the voltage change time on the oscilloscope to obtain the action time Ta of the microwave multi-channel delay component under test.

[0021] Beneficial effects: This invention uses conventional laboratory instruments to build a measurement system. The action time of the microwave multi-channel delay component under test is obtained through simple measurement steps. The judgment is based only on the output result after the microwave multi-channel delay component completes its action, without considering factors such as cable delay. Compared with the prior art, it is low in cost and easy to implement. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the measurement system. Figure 2This is the waveform displayed on the oscilloscope after the command sequence is sent. Figure 3 , Figure 4 To obtain the waveform displayed on the oscilloscope during the action time. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings. The drawings and detailed description do not constitute any limitation on the present invention.

[0024] See Figure 1 This embodiment proposes a system for measuring the action time of a microwave multi-channel delay component. The system includes a microwave signal source, a microwave N-channel power divider connected to the microwave signal source, the output of the microwave N-channel power divider connected to the microwave multi-channel delay component under test, the output of the microwave multi-channel delay component connected to a microwave N-channel combiner, the output of the microwave N-channel combiner connected to a detector, the output of the detector connected to a pulse time measuring device, and the microwave multi-channel delay component also connected to a command sending device via a communication interface.

[0025] A microwave signal source generates a microwave signal with a fixed frequency and amplitude. The output of the signal source is connected to the input of a microwave N-channel power divider. The power divider divides the input signal into N microwave signals with the same phase and amplitude to match the microwave multi-channel delay component and outputs N independent signals to the input port of the device under test.

[0026] N microwave signals are output from the microwave multi-channel delay component and input to the corresponding input terminals of the microwave N-channel combiner. The combiner combines the processed N signals into a single integrated microwave signal and outputs it to the detector.

[0027] The detector converts the microwave signal amplitude into a voltage signal and outputs it to the pulse time measurement device. In this embodiment, an envelope detector is used.

[0028] The pulse time measuring device detects the final voltage change time.

[0029] N≥2. Ideally, N is equal to the number of channels in the multi-channel delay component. However, the number of channels in the multi-channel delay component is not limited to the number of N. In the simplest system, a 2-channel power divider and combiner can be used.

[0030] The microwave multi-channel delay component is controlled by an instruction control device, which can generate and send a digital instruction sequence with a precise time interval (the time interval between two instructions is precisely adjustable at the microsecond level) to set the delay of each signal in the microwave multi-channel delay component.

[0031] In this embodiment, the pulse time measurement device is an oscilloscope with a bandwidth ≥ 20MHz.

[0032] Oscilloscopes with bandwidths of 20MHz-100MHz are commonly used equipment in laboratories. They are inexpensive (1000-3000 yuan) and have an effective time resolution of 17.5-3.5 nanoseconds. They can automatically measure and store values ​​such as period, frequency, rise time, fall time, positive pulse width, negative pulse width, positive duty cycle, negative duty cycle, maximum value time, minimum value time, positive slope, negative slope, delay 1→2t, delay 1→2t, phase 1→2f, phase 1→2t, maximum value, minimum value, peak-to-peak value, peak value, bottom value, amplitude, high value, median value, low value, average value, RMS value, overshoot, preshoot, area, period area, period RMS value, and variance.

[0033] The action time of the microwave multi-channel delay component controlled by the command from receiving the control command to the completion of the final execution action of each delay is in the sub-millisecond range (μs). In the method proposed in this invention, the measurement error is mainly determined by the time resolution of the oscilloscope. In this embodiment, an ordinary oscilloscope is selected as the pulse time measurement device, which can fully meet the requirements.

[0034] The instruction sending device can be an FPGA, a microcontroller, etc. In this embodiment, a computer is used as the instruction sending device.

[0035] The communication interfaces between the microwave multi-channel delay component and the host computer include Ethernet interface, RS232 / 485 / 422 serial port, SPI interface, etc., providing a rich set of computer interfaces that can be configured for different interfaces.

[0036] Based on the above system, this invention also proposes an embodiment of a method for measuring the action time of a microwave multi-channel delay component, comprising the following steps: S1: Set up the measurement system.

[0037] S2: Turn on the microwave signal source and output a sine wave. Its signal expression is: S(t) = A * cos(ωt + φ_0), where A is the amplitude of the signal, ω is the angular frequency of the signal, and φ_0 is the initial phase.

[0038] S3: The instruction sending device continuously sends a sequence of instructions, including instruction 1 and instruction 2.

[0039] Command 1 sets the delay of half of the channels to 0, and the delay of the other half of the channels to a value that creates a 180° phase difference at the test frequency. Command 2 sets the delay of all channels to 0.

[0040] The component is used to set the delay. The delay required for the output waveform to form a 180-degree phase difference is different at different frequencies. This delay needs to be calculated based on the test frequency and then set into the component. The test frequency is the signal frequency generated by the microwave signal source.

[0041] Under the action of command 1, the outputs of the microwave multi-channel delay component have two forms: both are sine waves, with one half being 180° out of phase with the other half.

[0042] S4: Change the time interval between instruction 1 and instruction 2, and observe the waveform on the oscilloscope until the waveform before and after the time interval change does not change.

[0043] S5: Read the voltage change time on the oscilloscope to obtain the action time Ta of the microwave multi-channel delay component under test.

[0044] The measurement principle of this invention is explained below.

[0045] The system has N channels, and all channels originate from the same signal source, having the same frequency and initial amplitude. The microwave signal source output signal expression is: S(t) = A * cos(ωt + φ_0), where A is the amplitude of each signal, ω is the angular frequency of the signal, and φ_0 is the initial phase.

[0046] A and ω are determined by the frequency range and maximum input power of the microwave multichannel delay component itself.

[0047] The expression for a single-channel signal after passing through the splitter: S F (t) = A / N*cos(ωt + φ_0).

[0048] Each microwave signal after passing through the device under test: The command sending device continuously sends a command sequence, which includes command 1 and command 2. Command 1 sets the delay of half of the channels to 0, and the delay of the other half of the channels is such that the delay forms a 180° phase difference at the test frequency. Command 2 sets the delay of all channels to 0.

[0049] Receive instruction 1. The expression for the output of half of the input signal channels in the microwave multi-channel delay component is: S F (t) = A / N*cos(ωt + φ_0), and the expression for the other half, which connects to the input signal channel output, is: S F (t) = A / N*cos(ωt + φ_0+180).

[0050] Receive instruction 2. The expression for the output of all connected input signal channels in the microwave multi-channel delay component is: S F (t) = A / N*cos(ωt + φ_0).

[0051] The combined signal expression is as follows: The combiner performs a linear superposition of voltage signals, and the total output signal is: SH (t) =ΣS F (t).

[0052] After receiving instruction 1: S H (t) =ΣS F (t) = N / 2*A / N*cos(ωt + φ_0)+ N / 2*A·cos(ωt +φ_0+ 180°) = A / 2*cos(ωt + φ_0) - A / 2*cos(ωt + φ_0) = 0.

[0053] After receiving instruction 2: S H (t) =ΣS F (t) = N*A / N*cos(ωt + φ_0) = A* cos((ωt + φ_0) = Microwave signal source output signal.

[0054] Upon receiving command 1, the signal passes through the detector and outputs 0. Upon receiving command 2, the signal passes through the detector and outputs the original input signal. On the oscilloscope, 0 represents a low level, and the original input signal represents a high level.

[0055] It is best to choose an even number for N to ensure that the signal output after passing through the detector after receiving command 2 is 0. If N is relatively large (e.g., N>10), and N is an odd number, the signal output after passing through the detector after receiving command 2 will not be 0, but it will still be significantly different from a high level and will not affect the final result.

[0056] The detector can convert microwave signals in two states into two different voltage values.

[0057] The waveform displayed on the oscilloscope at this time is as follows: Figure 2 As shown, t0 is the time when the microwave multi-channel delay component receives command 1, t1 is the time when command 1 is completed (the falling edge of the voltage on the oscilloscope), t2 is the time when the microwave multi-channel delay component receives command 2, and t3 is the time when command 2 is completed (the rising edge of the voltage on the oscilloscope).

[0058] The action time is Ta = t1 - t0 = t3 - t2, the time interval between sending command 1 and command 2 is t2 - t0, and the time that the oscilloscope can measure is Tc = t3 - t1. At this time, Tc is not equal to Ta.

[0059] By continuously reducing the interval between the two command transmissions, when t2 = t1, the time interval between the transmission of command 1 and command 2 is equal to Ta. This is reflected on the oscilloscope as follows: Figure 3 As shown, Tc reaches its minimum value at this time, and Ta = Tc.

[0060] In actual measurements, it is difficult to achieve perfect alignment between time points t2 and t1.

[0061] When the interval between two instruction transmissions is reduced to \(t2 < t1\), and the microwave multi-channel delay component receives another instruction during the execution of an instruction, it will cache this instruction and wait to execute the cached instruction immediately after the current instruction is completed. In this case, \(Tc\) will not change, that is, as Figure 4 shown. Utilizing this characteristic, the test conditions can be relaxed. There is no need to require \(t2 = t1\). When \(t2 < t1\), a measurable waveform will appear on the oscilloscope.

[0062] In implementation, at the start of the test, the interval between two instruction transmissions can be set to be less than the estimated value of the action time of the measured microwave multi-channel delay component. In this case, when the time interval between Instruction 1 and Instruction 2 is further reduced, the waveforms before and after the change in the time interval remain unchanged, and the obtained waveform can be measured.

[0063] In order to observe the change in the waveform during the test, in step S3, the time interval between Instruction 1 and Instruction 2 is \(t\), and \(t\) is greater than the estimated value of the action time of the measured microwave multi-channel delay component.

[0064] The action time of the microwave multi-channel delay component is generally 200 - 300 μs. In this embodiment, \(t\) is set to the estimated value + 50 μs.

[0065] In step S4, change the time interval between Instruction 1 and Instruction 2, each time reducing it by 1% of the estimated value, and observe the waveform on the oscilloscope until the waveforms before and after the change in the time interval remain unchanged.

[0066] The present invention also proposes an embodiment for verifying the action time on the measurement system: Take \(Ta\) as the time interval between Instruction 1 and Instruction 2, and the instruction sending device continuously sends an instruction sequence to obtain Waveform 1 on the oscilloscope.

[0067] Increase the time interval between Instruction 1 and Instruction 2, and the instruction sending device continuously sends an instruction sequence. At this time, the waveform of the voltage change on the oscilloscope should become wider.

[0068] Reduce the time interval between Instruction 1 and Instruction 2, and the instruction sending device continuously sends an instruction sequence. At this time, the waveform of the voltage change on the oscilloscope should recover to Waveform 1.

[0069] The increased or decreased time can be less than 1% of \(Ta\).

[0070] Observe three waveforms on the oscilloscope to verify the value of \(Ta\). If it conforms to the expected change, the value of \(Ta\) is correct.

Claims

1. A system for measuring the action time of a microwave multi-channel delay component, characterized in that, The system includes a microwave signal source, a microwave N-channel power divider connected to the microwave signal source, the output of the microwave N-channel power divider connected to the microwave multi-channel delay component under test, the output of the microwave multi-channel delay component connected to a microwave N-channel combiner, the output of the microwave N-channel combiner connected to a detector, the output of the detector connected to a pulse time measuring device, and the microwave multi-channel delay component also connected to a command sending device via a communication interface. The pulse time measuring device is an oscilloscope.

2. The system according to claim 1, characterized in that, The N≥2.

3. The system according to claim 1, characterized in that, The instruction sending device is a computer, and the communication interface includes an Ethernet interface, an RS232 / 485 / 422 serial port, and an SPI interface.

4. The system according to claim 1, characterized in that, The bandwidth of the oscilloscope is ≥20MHz.

5. A method for measuring the action time of a microwave multi-channel delay component, implemented based on the microwave multi-channel delay component action time measurement system described in claim 1, characterized in that, Includes the following steps: S1: Set up the measurement system; S2: Turn on the microwave signal source and output a sine wave; S3: The instruction sending device continuously sends an instruction sequence, which includes instruction 1 and instruction 2; Command 1 sets the delay of half of the channels to 0, and the delay of the other half of the channels to a value that creates a 180° phase difference at the test frequency. Command 2 sets the delay of all channels to 0. S4: Change the time interval between instruction 1 and instruction 2, and observe the waveform on the oscilloscope until the waveform before and after the time interval change does not change; S5: Read the voltage change time on the oscilloscope to obtain the action time Ta of the microwave multi-channel delay component under test.

6. The method according to claim 5, characterized in that, In step S3, the time interval between instruction 1 and instruction 2 is t, where t is greater than the estimated value of the action time of the microwave multi-channel delay component under test. In step S4, the time interval between instruction 1 and instruction 2 is changed, and the estimated value is reduced by 1% each time.

7. The method according to claim 5, characterized in that, Using Ta as the time interval between instruction 1 and instruction 2, the instruction sending device continuously sends the instruction sequence. Increase the time interval between instruction 1 and instruction 2, and the instruction sending device continuously sends the instruction sequence. The time interval between instruction 1 and instruction 2 is reduced, and the instruction sending device continuously sends the instruction sequence. Observe the three waveforms on the oscilloscope to verify the Ta value.

Images