A variable local oscillator delay frequency synthesizer receiver

Abstract

The variable local oscillator delay frequency synthesizer receiver comprises a waveform generation and control module, a frequency synthesizer and a radio frequency receiver, the waveform generation and control module outputs a variable delay wideband intermediate frequency LFM signal or a variable delay intermediate frequency point frequency signal to the frequency synthesizer, the variable delay wideband intermediate frequency LFM signal or the variable delay intermediate frequency point frequency signal is multiplied and mixed by the frequency synthesizer to obtain a variable delay local oscillator signal; the radio frequency receiver receives the variable delay local oscillator signal and a radio frequency echo signal, the radio frequency echo signal is modulated by the variable delay local oscillator signal to obtain an intermediate frequency echo signal output; the time delay of the variable delay local oscillator signal is adjusted according to the radio frequency echo signal, when the radio frequency echo signal slanting angle changes, the time delay of the local oscillator signal is changed, so that the local oscillator signal is always located in the middle of the near-end echo signal and the far-end echo signal. The application well reduces the echo bandwidth of the spaceborne super high resolution radar.

Description

Technical Field

[0001] This invention relates to micromillimeter wave high bandwidth signal transceiver technology, specifically to a variable local oscillator delay frequency synthesizer receiver. Background Technology

[0002] Spaceborne ultra-high resolution radar employs a wide pulse width transmission and beat reception method to reduce peak power and echo bandwidth. Traditional beat reception uses the signal from the center of the scene at any given moment for beat reception, meaning the beat local oscillator signal is precisely in the middle of the near-end and far-end echoes, resulting in the minimum echo bandwidth after the beat. The beat reception bandwidth is related to the observation swath width and the transmitted signal bandwidth (proportional to the resolution). Given a fixed swath width, the higher the resolution, the larger the beat reception bandwidth. In the traditional small-angle sliding beamforming mode, the beat reception bandwidth uses a fixed local oscillator delay during a single imaging process. As the scanning angle changes, the near-end and far-end echo delays shift, resulting in an actual beat reception bandwidth greater than the ideal beat reception bandwidth. This makes reducing the intermediate frequency echo bandwidth a technical challenge for spaceborne ultra-high resolution radar. Summary of the Invention

[0003] The purpose of this invention is to provide a variable frequency delay receiver to solve the problem of large echo bandwidth in spaceborne ultra-high resolution radar reception.

[0004] To achieve the above objectives, the present invention provides a variable local oscillator delay frequency synthesizer receiver, comprising a waveform generation and control module, a frequency synthesizer, and an RF receiver. The waveform generation and control module outputs a variable delay broadband intermediate frequency (LFM) signal or a variable delay intermediate frequency point frequency signal to the frequency synthesizer, which multiplies and mixes the signal to obtain a variable delay local oscillator signal. The RF receiver receives the variable delay local oscillator signal and the RF echo signal, and modulates the RF echo signal using the variable delay local oscillator signal to obtain an intermediate frequency echo signal output. The delay of the variable delay local oscillator signal is adjusted according to the RF echo signal. When the angle of view of the RF echo signal changes, the delay of the local oscillator signal is changed to ensure that the local oscillator signal is always located in the middle between the near-end echo signal and the far-end echo signal.

[0005] In the aforementioned variable local oscillator delay frequency synthesizer receiver, the variable delay local oscillator signal output by the frequency synthesizer switches between a broadband radio frequency LFM signal and a radio frequency point frequency signal, but remains fixed during a single operation.

[0006] In the aforementioned variable local oscillator delay frequency synthesizer receiver, when the RF echo signal bandwidth is >1.2GHz, the RF receiver adopts beat reception mode, and the first output channel of the waveform generation and control module outputs a variable delay broadband intermediate frequency (LFM) signal. The variable delay local oscillator signal output by the frequency synthesizer is a variable delay broadband RF LFM signal. When the RF echo signal bandwidth is ≤1.2GHz, the RF receiver adopts direct reception mode, and the first output channel of the waveform generation and control module outputs a variable delay intermediate frequency (IF) spot frequency signal. The variable delay local oscillator signal output by the frequency synthesizer is a variable delay RF spot frequency signal.

[0007] The aforementioned variable local oscillator delay frequency synthesizer has a maximum bandwidth of >5GHz for the variable delay broadband local oscillator signal and a maximum bandwidth of >5GHz for the radio frequency echo signal.

[0008] Compared with the prior art, the beneficial technical effects of the present invention are:

[0009] This invention enables the local oscillator signal to switch between a variable delay broadband LFM signal and a variable delay point frequency signal, and the delay of the local oscillator signal is adjustable. When the angle of view of the radio frequency echo signal changes, the delay of the local oscillator signal can be changed to ensure that the local oscillator signal is always located in the middle of the near-end and far-end echo signals, which effectively reduces the echo bandwidth of the spaceborne ultra-high resolution radar. Attached Figure Description

[0010] The variable oscillator delay frequency synthesizer of the present invention is given by the following embodiments and figures.

[0011] Figure 1 This is a block diagram of a variable oscillator delay frequency synthesizer receiver according to a preferred embodiment of the present invention. Detailed Implementation

[0012] The following will combine Figure 1 The variable oscillator delay frequency synthesizer of the present invention will be described in further detail.

[0013] Fixed local oscillator delay beat reception suffers from the problem that the near-end and far-end echo delays shift with changes in the scanning angle, resulting in an actual beat reception bandwidth that is larger than the ideal beat reception bandwidth, making it difficult to reduce the echo bandwidth of spaceborne ultra-high resolution radar. This invention aims to solve this technical problem.

[0014] Figure 1 The diagram shown is a block diagram of a variable oscillator delay frequency synthesizer receiver according to a preferred embodiment of the present invention.

[0015] join Figure 1 The variable local oscillator delay frequency synthesizer receiver in this embodiment includes a waveform generation and control module, a frequency synthesizer, an RF receiver, and a secondary power supply;

[0016] The waveform generation and control module has two output channels. The first output channel outputs a variable delay broadband intermediate frequency LFM signal (i.e., a broadband intermediate frequency linear frequency modulation signal) or a variable delay intermediate frequency point frequency signal. The second output channel outputs a broadband intermediate frequency LFM signal (without delay).

[0017] The variable-delay broadband intermediate frequency (LFM) signal or variable-delay intermediate frequency point frequency signal output from the first output channel of the waveform generation and control module is multiplied and mixed by the frequency synthesizer to obtain a Ka-band variable-delay local oscillator signal. The delay amount of the Ka-band variable-delay local oscillator signal is adjustable.

[0018] The broadband intermediate frequency (LFM) signal output from the second output channel of the waveform generation and control module is multiplied and mixed by the frequency synthesizer to obtain the Ka-band transmission excitation signal and the radio frequency calibration signal.

[0019] The radio frequency receiver receives the Ka-band variable delay local oscillator signal and the radio frequency echo signal, and uses the Ka-band variable delay local oscillator signal to modulate the radio frequency echo signal to obtain an intermediate frequency echo signal output.

[0020] The secondary power supply provides power to the waveform generation and control module, the frequency synthesizer, and the radio frequency receiver.

[0021] When the first output channel of the waveform generation and control module outputs a variable delay broadband intermediate frequency (LFM) signal, the variable delay local oscillator signal output by the frequency synthesizer is a variable delay broadband radio frequency (LFM) signal; for the variable delay broadband radio frequency (LFM) signal (local oscillator signal), the radio frequency receiver adopts a beat reception mode;

[0022] When the first output channel of the waveform generation and control module outputs a variable delay intermediate frequency signal, the variable delay local oscillator signal output by the frequency synthesizer is a variable delay radio frequency signal; for the variable delay radio frequency signal (local oscillator signal), the radio frequency receiver adopts a direct reception mode.

[0023] In this embodiment, the delay of the local oscillator signal output by the frequency synthesizer is adjustable. When the angle of view of the radio frequency echo signal changes, the delay of the local oscillator signal is changed to ensure that the local oscillator signal is always located in the middle between the near-end echo signal and the far-end echo signal. The delay of the local oscillator signal (i.e., the delay amount) is determined based on the radio frequency echo signal received by the radio frequency receiver.

[0024] In this embodiment, the local oscillator signal output by the frequency synthesizer can switch between a variable delay broadband LFM signal and a variable delay point frequency signal, but remains fixed during a single operation.

[0025] In this embodiment, when the bandwidth of the radio frequency echo signal received by the radio frequency receiver is greater than 1.2 GHz, the radio frequency receiver adopts the beat reception mode, and the first output channel of the waveform generation and control module outputs a variable delay broadband intermediate frequency (LFM) signal; when the bandwidth of the radio frequency echo signal is less than or equal to 1.2 GHz, the radio frequency receiver adopts the direct reception mode, and the first output channel of the waveform generation and control module outputs a variable delay intermediate frequency (LFM) spot frequency signal.

[0026] In this embodiment, the variable delay broadband radio frequency LFM signal (local oscillator signal) output by the frequency synthesizer has a maximum bandwidth of >5GHz; the transmit excitation signal and radio frequency calibration signal output by the frequency synthesizer have a maximum bandwidth of >5GHz; and the radio frequency echo signal received by the radio frequency receiver has a maximum bandwidth of >5GHz.

[0027] This invention enables the local oscillator signal to switch between a variable delay broadband LFM signal and a variable delay point frequency signal, and the delay of the local oscillator signal is adjustable. When the angle of view of the radio frequency echo signal changes, the delay of the local oscillator signal can be changed to ensure that the local oscillator signal is always located in the middle of the near-end and far-end echo signals, which effectively reduces the echo bandwidth of the spaceborne ultra-high resolution radar.

Claims

1. A variable local oscillator delay frequency synthesizer receiver, comprising a waveform generation and control module, a frequency synthesizer, and an RF receiver, characterized in that, The waveform generation and control module outputs a variable delay broadband intermediate frequency (LFM) signal or a variable delay intermediate frequency point frequency signal to the frequency synthesizer. After frequency multiplication and mixing by the frequency synthesizer, a variable delay local oscillator signal is obtained. The radio frequency receiver receives the variable delay local oscillator signal and the radio frequency echo signal, and uses the variable delay local oscillator signal to modulate the radio frequency echo signal to obtain an intermediate frequency echo signal output. The delay of the variable delay local oscillator signal is adjusted according to the radio frequency echo signal. When the angle of the radio frequency echo signal changes, the delay of the local oscillator signal is changed so that the local oscillator signal is always located in the middle between the near-end echo signal and the far-end echo signal. The variable local oscillator delay frequency synthesizer outputs a variable delay local oscillator signal that switches between a broadband radio frequency LFM signal and a radio frequency point frequency signal, but remains fixed during a single operation.

2. The variable local oscillator delay frequency synthesizer receiver as described in claim 1, characterized in that, When the RF echo signal bandwidth is >1.2GHz, the RF receiver adopts beat reception mode, and the first output channel of the waveform generation and control module outputs a variable delay broadband intermediate frequency (LFM) signal. The variable delay local oscillator signal output by the frequency synthesizer is a variable delay broadband RF LFM signal. When the RF echo signal bandwidth is ≤1.2GHz, the RF receiver adopts direct reception mode, and the first output channel of the waveform generation and control module outputs a variable delay intermediate frequency (IF) spot frequency signal. The variable delay local oscillator signal output by the frequency synthesizer is a variable delay RF spot frequency signal.

3. The variable local oscillator delay frequency synthesizer receiver as described in claim 1, characterized in that, The maximum bandwidth of the variable delay broadband local oscillator signal is >5GHz; the maximum bandwidth of the radio frequency echo signal is >5GHz.

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