Microwave testing device and method for multipath influence suppression in external field environment

Abstract

The invention discloses a microwave test device and method for multipath influence suppression in an external field environment, the test device comprises a vector network analyzer, amplitude and phase modulation equipment, a transmitting antenna and a receiving antenna, and the method comprises the following steps: searching a time domain window by using the distance R between the transmitting antenna and the receiving antenna; a transmitting antenna switch is turned off, a vector network analyzer is switched to a time domain mode, a time domain axis range is set to be 0-(R / 0.3 + 50) nanoseconds, the transmitting antenna switch is turned on, at the moment, a transmitted signal appears in a time domain, another crest value appears at the position, the crest value is a signal caused by multiple paths, the leading edge of the signal is set to be the central position of a time domain window, and the crest value is set to be the central position of the time domain window. The width of the time domain window is set to be 200 picoseconds, and multipath signals can be isolated at the moment; and then the time domain window position and the multipath effect suppression effect are verified. According to the system testing method, the multipath effect is improved to the greatest extent under the condition that physical structures such as the antenna aperture received by a testing system are not changed.

Description

Technical Field

[0001] This invention relates to electronic signal processing technology, specifically to a microwave testing device and method for suppressing multipath effects in an external environment, belonging to the field of electronics and communications. Background Technology

[0002] In field testing scenarios, due to the complexity of the actual environment, the signal will encounter multiple reflections from various objects such as buildings and vegetation during propagation, which will cause multipath effects. This will cause distortions such as phase interference and amplitude fading in the signal received by the receiving antenna, ultimately reducing the accuracy of the received signal.

[0003] Existing multipath suppression techniques employ diversity methods, which require changes to the signal transmission method, antenna structure, and antenna polarization. However, these methods make signal processing more complex and reduce spectrum utilization. Summary of the Invention

[0004] This invention discloses a microwave testing device and method for suppressing multipath effects in an outdoor environment. It uses a time-domain window approach to suppress multipath effects, and maximizes the improvement of multipath effect system testing methods without changing the physical structure of the receiving antenna aperture and other physical structures of the testing system, and without changing the phase and other information of the receiving system.

[0005] The above objectives are achieved through the following technical solutions:

[0006] The present invention first provides a microwave test device for suppressing multipath effects in an outdoor environment. The test device includes a vector network analyzer, an amplitude and phase modulation device, a transmitting antenna, and a receiving antenna. Port 1 of the vector network analyzer is connected to the receiving antenna, and port 2 of the vector network analyzer transmits signals and is connected to the amplitude and phase modulation device and a switch before being connected to the transmitting antenna. The distance between the transmitting antenna and the receiving antenna is R.

[0007] The present invention also provides a microwave testing method for suppressing multipath effects in an external field environment using the above-mentioned microwave testing device for suppressing multipath effects in an external field environment. The method includes the following steps:

[0008] Step 1: Construct the testing apparatus as described in claim 1;

[0009] Step 2: Using the distance R between the transmitting and receiving antennas, locate the time-domain window; turn off the transmitting antenna switch, switch the vector network analyzer to time-domain mode, and determine the time-domain window based on the distance R (in meters) and the speed of light. Set the time domain axis range to 0~(R / 0.3+50) nanoseconds, turn on the transmit antenna switch, and the signal transmitted by the transmit antenna will appear in the time domain, and another peak will appear at this position. This value is the signal caused by multipath. Set the leading edge of the signal to the center position of the time domain window, and set the width of the time domain window to 200 picoseconds. At this time, multipath signals can be isolated.

[0010] Step 3, verify the position of the time-domain window; turn on the switch located at the transmitting antenna. At this time, the receiving antenna will receive the signal. Compare the signal received in the vector network time domain with the signal when there is no signal. If you see a signal at point R, the position of the time-domain window is correct.

[0011] Step 4: Verify the multipath effect suppression effect.

[0012] Further, the specific method of step 4 is as follows: When the signal has multipath effects, the amplitude and phase values ​​adjusted by the device will be inaccurate. Therefore, by adjusting the amplitude and phase values ​​of the device, analyze whether the amplitude and change of the acquired signal are consistent with the adjusted values. If they are consistent, it indicates that the multipath effect of the signal has been suppressed. Switch the vector network analyzer to frequency domain mode, such as adjusting the amplitude and phase modulation device, setting the attenuation to AdB, and observing the amplitude attenuation of the vector network analyzer to AdB, and setting the phase modulation device to phase shift. The phase change observed by the vector network analyzer should be [degrees]. Spend.

[0013] Compared with the prior art, the significant advantages of the present invention are:

[0014] This invention provides a microwave testing method for suppressing multipath effects in outdoor environments. The advantage of this method is that, without altering the physical structure of the test system, such as the receiving antenna aperture, it minimizes the impact of multipath effects on the test system in a relatively convenient manner. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the steps of a microwave testing method for suppressing multipath effects in an external field environment, as proposed in this invention.

[0016] Figure 2 Connection diagram for the test scenario;

[0017] Figure 3 The interface for setting up the time domain of a vector network analyzer;

[0018] Figure 4 This is a time-domain window plot of the signal;

[0019] Figure 5 This is a verification chart for amplitude adjustment;

[0020] Figure 6 This is a phase adjustment verification diagram. Detailed Implementation

[0021] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0022] like Figure 1 The diagram shows the microwave testing method for suppressing multipath effects in an external environment. The specific steps are as follows:

[0023] Step 1, set up the test scenario, such as Figure 2 As shown. A signal is transmitted through port 2 of the vector network analyzer, connected to amplitude and phase modulation equipment and a switch, and then connected to an antenna. Another receiving antenna is located at a distance R from the transmitting antenna and is connected to port 1 of the vector network analyzer.

[0024] Where R represents the distance between the receiving antenna and the transmitting antenna;

[0025] Step 2: Locate the time-domain window using the distance between the transmitting and receiving antennas; turn off the transmitting antenna switch and switch the vector network analyzer to time-domain mode, such as... Figure 3 As shown. Based on the scene distance R meters and the speed of light propagation. Set the time-domain axis range to 0 to (R / 0.3+50) nanoseconds. Turn on the transmit antenna switch. At this time, the signal transmitted by the transmit antenna will appear in the time domain. Figure 3 The signal appears at 292.89 nanoseconds, and another peak appears at 293 nanoseconds. This is a signal caused by multipath. Setting the leading edge of this signal at 292.89 nanoseconds is the center position of the time domain window, and the width of the window is set to 200 picoseconds. This can isolate the multipath signal.

[0026] Step 3, verify the time-domain window position; turn on the switch located at the transmitting antenna. At this time, the receiving antenna will receive the signal. Compare the signal received in the vector network time domain with the signal received when there is no signal. Figure 4 As shown, a signal can be seen at point R, indicating that the time-domain window is in the correct position.

[0027] Step 4: Verify the multipath effect suppression effect. When multipath effects exist in the signal, the amplitude and phase values ​​adjusted by the device will be inaccurate. Therefore, by adjusting the amplitude and phase values ​​of the device, analyze whether the amplitude and change of the acquired signal are consistent with the adjusted values. If they are consistent, it indicates that the multipath effect of the signal has been suppressed. Switch the vector network analyzer to frequency domain mode, such as adjusting the amplitude and phase modulation device, setting the attenuation to AdB, and observe the amplitude attenuation of the vector network analyzer to AdB. Figure 5 As shown. The phase modulation device is configured to shift the phase. The phase change observed by the vector network analyzer should be [degrees]. Degree, such as Figure 6 As shown.

[0028] The above are merely preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, under the guidance of the present invention, can make many other forms without departing from the spirit and scope of the claims of the present invention, and all of these are within the protection scope of the present invention.

Claims

1. A microwave testing device for suppressing multipath effects in an external environment, characterized in that, The test setup includes a vector network analyzer, an amplitude and phase modulation device, a transmitting antenna, and a receiving antenna. Port 1 of the vector network analyzer is connected to the receiving antenna, and port 2 of the vector network analyzer transmits signals. After being connected to the amplitude and phase modulation device and a switch, the transmitting antenna is connected. The distance between the transmitting antenna and the receiving antenna is R.

2. A microwave testing method for suppressing multipath effects in an external field environment using the microwave testing apparatus for suppressing multipath effects in an external field environment as described in claim 1, characterized in that, The method includes the following steps: Step 1: Construct the testing apparatus as described in claim 1; Step 2: Using the distance R between the transmitting and receiving antennas, locate the time-domain window; turn off the transmitting antenna switch, switch the vector network analyzer to time-domain mode, and determine the time-domain window based on the distance R (in meters) and the speed of light. Set the time domain axis range to 0~(R / 0.3+50) nanoseconds, turn on the transmit antenna switch, and the signal transmitted by the transmit antenna will appear in the time domain, and another peak will appear at this position. This value is the signal caused by multipath. Set the leading edge of the signal to the center position of the time domain window, and set the width of the time domain window to 200 picoseconds. At this time, multipath signals can be isolated. Step 3, verify the position of the time-domain window; turn on the switch located at the transmitting antenna. At this time, the receiving antenna will receive the signal. Compare the signal received in the vector network time domain with the signal when there is no signal. If you see a signal at point R, the position of the time-domain window is correct. Step 4: Verify the multipath effect suppression effect.

3. The test method according to claim 2, characterized in that, Step 4 is specifically as follows: When multipath effects exist in the signal, the amplitude and phase values ​​adjusted by the device will be inaccurate. Therefore, by adjusting the amplitude and phase values ​​of the device, analyze whether the amplitude and change of the acquired signal are consistent with the adjusted values. If they are consistent, it indicates that the multipath effect of the signal has been suppressed. Switch the vector network analyzer to frequency domain mode, such as adjusting the amplitude and phase modulation devices, setting the attenuation to AdB, and observing the amplitude attenuation of the vector network analyzer to AdB, and setting the phase modulation device to phase shift. The phase change observed by the vector network analyzer should be [degrees]. Spend.

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