A deskew mechanism for a wideband frequency source

Abstract

The application provides a de-skew broadband frequency source, wherein the output end of a reference source P1 is connected with the input end of a power division amplification circuit; the output of the power division amplification circuit U1 is respectively used as the reference input signal of a point frequency source P2, a frequency source P3 and a frequency source P4; the output end of the point frequency source P2 is connected with the input end of a broadband waveform circuit; the output end of the broadband waveform circuit U2 is connected with the input end of a transceiver switch S1; the two optional output ends of the transceiver switch S1 are respectively connected with the intermediate frequency input end of a mixing module U3 and a mixing module U4; the output end of the frequency source P3 is connected with the local oscillator input end of the mixing module U3; the output end of the frequency source P4 is connected with the local oscillator input end of the mixing module U4; the output signal of the mixing module U3 is output to a transmitter as an excitation signal of radar emission; and the output signal of the mixing module U4 is output to a radar receiving front end as a local oscillator signal of a radar receiver. The application can meet the requirement of a frequency source of a broadband measurement imaging radar based on a de-skew system.

Description

Technical Field

[0001] This invention relates to radar measurement and imaging technology, and in particular to a deskewing broadband frequency source. Background Technology

[0002] In fields such as radar and communications, broadband signals can acquire more target information. Conventional broadband signal processing involves directly receiving the signal and then sampling it. This method requires a high analog-to-digital (AD) sampling rate. However, under current technological conditions, the AD sampling rate is limited by the capabilities of the devices, making it difficult to further increase the signal bandwidth. Simultaneously, a higher sampling rate leads to a significant increase in the amount of data processed. This necessitates corresponding improvements in processing power, storage capacity, I / O interfaces, power supply, and heat dissipation, further increasing the system's equipment requirements and technical implementation complexity.

[0003] Deskewing reception can be used to solve this problem. Deskewing reception can directly convert the target echo of a broadband signal into a single-frequency signal. At the same time, the frequency value of this signal can be controlled by the time delay of the echo signal and the reference signal during the implementation process. A lower sampling rate can be used, thereby reducing the system's requirements for AD and back-end data processing. Therefore, the signal bandwidth can be further improved and the number of devices can be significantly reduced.

[0004] However, deskewing receivers place higher demands on the frequency source, mainly in the following aspects: (1) The local oscillator changes from a conventional continuous wave signal to a broadband linear frequency modulated signal. (2) The timing control requirements for the local oscillator are increased, that is, the local oscillator must be generated within the time period occupied by the target echo. Summary of the Invention

[0005] The purpose of this invention is to propose a de-skewed broadband frequency source to meet the frequency source requirements of broadband measurement and imaging radar based on the de-skewed system.

[0006] The technical solution to achieve the purpose of this invention is: a de-skewed broadband frequency source, comprising: a reference source P1, a power divider amplifier circuit U1, a point frequency source P2, a broadband waveform circuit U2, a transceiver switch S1, a frequency source P3, a frequency source P4, a mixer module U3, and a mixer module U4, wherein:

[0007] The output of reference source P1 is connected to the input of the power divider amplifier circuit; the output of the power divider amplifier circuit U1 serves as the reference input signal for the point frequency source P2, frequency source P3, and frequency source P4, respectively; the output of point frequency source P2 is connected to the input of the broadband waveform circuit; the output of the broadband waveform circuit U2 is connected to the input of the transceiver switch S1; the two outputs of the transceiver switch S1 are connected to the intermediate frequency inputs of the mixer module U3 and the mixer module U4, respectively; the output of frequency source P3 is connected to the local oscillator input of the mixer module U3; the output of frequency source P4 is connected to the local oscillator input of the mixer module U4; the output signal of the mixer module U3 is output to the transmitter as the excitation signal for radar transmission; the output signal of the mixer module U4 is output to the radar receiver front end as the local oscillator signal of the radar receiver.

[0008] The aforementioned de-skewed broadband frequency source operates as follows:

[0009] The reference source P1 generates a reference clock signal with a frequency of 100MHz; the power divider amplifier circuit U1 amplifies the signal from the reference source P1 and outputs it to the point frequency source P2, frequency source P3, and frequency source P4 respectively; the point frequency source P2 adopts an analog phase-locked dielectric oscillator and has an output frequency of f. c The point frequency signal serves as the input reference clock signal for the broadband waveform circuit U2. The broadband waveform circuit U2 is a broadband pulse waveform generation circuit based on DDS, providing a broadband linear frequency modulated signal with a frequency range of f1 to f2, where f1 and f2 refer to frequencies. The transceiver switch S1 is used to switch between the transmit channel and the local oscillator signal channel. The local oscillator needs to be generated within the time period occupied by the target echo. The frequency source P3 and frequency source P4 are composed of multiple point frequency sources and switching components, providing local oscillator signals to the mixing modules U3 and U4, respectively. The mixing module U3 is used to upconvert the broadband linear frequency modulated signal f1 to f2 to a signal f3 to f4, providing an excitation signal for the radar transmitter, where f3 and f4 refer to frequencies. The mixing module U4 is used to upconvert the broadband linear frequency modulated signal f1 to f2 to a signal f5 to f6, providing a deskewing signal for the local oscillator of the radar receiver, where f5 and f6 refer to frequencies.

[0010] The reference source P1 uses a 100MHz low-phase-noise temperature-controlled crystal oscillator with a frequency setting accuracy better than 3×10⁻⁶. -7 Spurious emissions are better than -70dBc, and phase noise is better than -165dBc / Hz@1kHz.

[0011] The broadband linear frequency modulation waveform generation circuit U2 outputs a broadband linear frequency modulation signal with a minimum frequency step of 1MHz and a signal bandwidth of 1.7GHz.

[0012] The broadband linear frequency modulation waveform generation circuit U2 adopts multi-channel parallel DDS technology to effectively increase the operating clock frequency of the DDS, thereby expanding the output bandwidth of the DDS.

[0013] In imaging mode, a transmission signal bandwidth of 1.7 GHz is used, with a maximum target imaging distance of better than 175 m and a target imaging resolution of less than 0.2 m.

[0014] Within one radar repetition cycle, the frequency source generates a broadband baseband signal based on the transmit excitation trigger signal and switches the transceiver switch S1 to the channel connecting S1 and the mixer module U3. The broadband baseband signal is then output after being mixed and amplified by the mixer module U3 to provide the transmit excitation signal for the radar transmitter. When the radar receives the echo signal, it sends a local oscillator trigger control signal to the frequency source. The frequency source generates a broadband baseband signal based on this signal and switches the transceiver switch S1 to the channel connecting S1 and the mixer module U4. The broadband baseband signal is then output after being mixed and amplified by the mixer module U4 to provide the de-skewing local oscillator signal for the radar receiver.

[0015] Compared with existing technologies, the significant advantages of this invention are: 1) It solves the problem of signal and data acquisition difficulties caused by the increase in signal bandwidth, and can easily handle linear frequency modulated signals with extremely large bandwidths. 2) The maximum linear frequency modulation range reaches 1700MHz, fully ensuring the integrity of the target phase information. The maximum target imaging distance is better than 175m, and the target imaging resolution is better than 0.2m. 3) Based on the de-skewing reception system, the target echo of the broadband signal is directly converted into a single-frequency signal. At the same time, the frequency value of this signal is controlled by the time delay of the echo signal and the reference signal during the implementation process, which reduces the requirements of the system on the AD and back-end processing. Therefore, the signal bandwidth can be further improved, and the number of devices can be significantly reduced. 4) The phase noise of the local oscillator and the transmitted excitation signal is better than -90dBc / Hz@1kHz. Attached Figure Description

[0016] Figure 1 This is a block diagram illustrating the principle of a de-skewed broadband frequency source.

[0017] Figure 2 This is a flowchart of the slant removal process for the entire machine in imaging mode.

[0018] Figure 3 This is a flowchart of the desampling process for the receiving channel in broadband imaging mode.

[0019] Figure 4 This is a waveform diagram of descrambling pulse compression in the receiving channel under broadband imaging mode.

[0020] Figure 5 This is a structural diagram of a broadband DDS in broadband imaging mode. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] A de-skewed broadband frequency source includes: a reference source P1, a power divider amplifier circuit U1, a point frequency source P2, a broadband waveform circuit U2, a transceiver switch S1, a frequency source P3, a frequency source P4, a mixer module U3, and a mixer module U4.

[0023] The reference source P1 is used to generate a reference signal with a frequency of 100MHz. The power divider amplifier circuit U1 amplifies the signal from the reference source P1 and outputs it to the point frequency source P2, frequency source P3, and frequency source P4 respectively. The point frequency source P2 uses an analog phase-locked dielectric oscillator with an output frequency of f. c The point frequency signal is used as the input reference signal of the broadband waveform circuit U2. The broadband waveform circuit U2 is a broadband pulse waveform generation circuit based on DDS, providing a broadband linear frequency modulated signal with a frequency range of f1 to f2, where f1 and f2 refer to frequencies. The transceiver switch S1 is used to switch between the transmit channel and the local oscillator signal channel. The frequency source P3 and frequency source P4 are composed of multiple point frequency sources and switching components, providing local oscillator signals to the mixing modules U3 and U4, respectively. The mixing module U3 is used to upconvert the broadband linear frequency modulated signal f1 to f2 to a signal f3 to f4, providing an excitation signal for the radar transmitter, where f1, f2, f3, and f4 refer to frequencies. The mixing module U4 is used to upconvert the broadband linear frequency modulated signal f1 to f2 to a signal f5 to f6, providing a deskewing signal for the local oscillator of the radar receiver, where f1, f2, f5, and f6 refer to frequencies.

[0024] The output of reference source P1 is connected to the input of the power divider amplifier circuit. The output of the power divider amplifier circuit U1 serves as the reference input signal for frequency sources P2, P3, and P4, respectively. The output of frequency source P2 is connected to the input of the broadband waveform circuit. The output of the broadband waveform circuit U2 is connected to the input of the transceiver switch S1. The two outputs of the transceiver switch S1 are connected to the intermediate frequency inputs of mixer modules U3 and U4, respectively. The output of frequency source P3 is connected to the local oscillator input of mixer module U3. The output of frequency source P4 is connected to the local oscillator input of mixer module U4. The output signal of mixer module U3 can be output to the transmitter as the excitation signal for radar transmission. The output signal of mixer module U4 can be output to the radar receiver front end as the local oscillator signal for the radar receiver.

[0025] This application provides a de-skewed broadband frequency source, which achieves the following specifications:

[0026] a) Frequency range of the transmitted excitation signal: f3~f4

[0027] b) Frequency range of a local oscillator signal: f5~f6

[0028] c) Maximum linear frequency modulation range: 1700MHz

[0029] d) Minimum frequency step interval: 1MHz

[0030] e) Frequency setting accuracy: 3×10⁻⁷

[0031] f) Phase noise of the local oscillator and emitter excitation: ≤-90dBc / Hz@1kHz (f3~f4)

[0032] This de-skewed broadband frequency source can serve as an ideal local oscillator for broadband measurement imaging radar transmitters and receivers. The increased signal bandwidth ensures high-precision range resolution, and the de-skewed pulse compression method guarantees data acquisition even with low-sampling-rate, high-precision AD converters. The advantage of this de-skewed broadband frequency source lies in its ability to simultaneously address the issues of ultra-high-precision range resolution and relatively low data sampling rates.

[0033] Example

[0034] To verify the effectiveness of the present invention, the following experiment was conducted.

[0035] Figure 1 This application provides a principle block diagram of one embodiment. It includes: a reference source P1, a power divider amplifier circuit U1, a point frequency source P2, a broadband waveform circuit U2, a transceiver switch S1, a frequency source P3, a frequency source P4, a mixer module U3, and a mixer module U4.

[0036] Reference source P1 uses a 100MHz low-phase-noise temperature-controlled crystal oscillator with a frequency setting accuracy better than 3×10⁻⁶. -7The spurious emissions are better than -70dBc, and the phase noise is better than -165dBc / Hz@1kHz. The output of reference source P1 is electrically connected to the input of the power divider amplifier circuit via an SMA connection. The output of the power divider amplifier circuit is electrically connected to the inputs of point frequency sources P2, P3, and P4 via SMA connections, respectively. The output of point frequency source P2 is electrically connected to the input of the broadband waveform circuit via an SMA connection. The output of the broadband waveform circuit U2 is electrically connected to the input of the transceiver switch S1 via an SMA connection. The two outputs of the transceiver switch S1 are electrically connected to the intermediate frequency inputs of mixer modules U3 and U4 via SMA connections, respectively. The output of frequency source P3 is electrically connected to the local oscillator input of mixer module U3 via an SMA connection. The output of frequency source P4 is electrically connected to the local oscillator input of mixer module U3 via an SMA connection. The output of mixer module U3 can be connected to the input of the radar transmitter via an SMA RF cable. The output of mixer module U4 can be connected to the local oscillator input of the radar receiver via an SMA RF cable.

[0037] The output signal of reference source P1, after passing through a power divider amplifier circuit, serves as the reference input signal for point frequency sources P2, frequency sources P3, and frequency sources P4, respectively. The output signal of point frequency source P2, after passing through a broadband waveform circuit U2, outputs a broadband linear frequency modulated (LFM) waveform with a bandwidth of 1700MHz. The 1700MHz broadband LFM signal output from the broadband waveform circuit U2 is then selected by the two output terminals of the transceiver switch S1, and output to the RF excitation branch where the mixer module U3 is located and the local oscillator signal branch where the mixer module U4 is located, respectively. The output signal of transceiver switch S1 when switched to the excitation channel and the output signal of frequency source P3, after up-conversion by mixer module U3, can be used as the excitation signal for the radar transmitter. The output signal of transceiver switch S1 when switched to the receiver channel and the output signal of frequency source P4, after up-conversion by mixer module U4, can be used as the local oscillator signal for the radar receiver in de-skew mode.

[0038] Figure 2 This is a flowchart illustrating the deskewing process performed based on the frequency source of this application during imaging.

[0039] Figure 3 The flowchart shows the deslant pulse compression process for the receiving channel in broadband imaging mode.

[0040] Figure 4 The waveform diagram for descrambling pulse compression in the receiving channel under broadband imaging mode.

[0041] Figure 5 This is a flowchart of the DDS workflow in broadband imaging mode.

[0042] This application provides a de-skewed broadband frequency source, which achieves the following specifications:

[0043] a) Frequency range of the transmitted excitation signal: f3~f4

[0044] b) Frequency range of a local oscillator signal: f5~f6

[0045] c) Maximum linear frequency modulation range: 1700MHz

[0046] d) Minimum frequency step interval: 1MHz

[0047] e) Frequency setting accuracy: 3×10⁻⁷

[0048] f) Phase noise of the local oscillator and emitter excitation: ≤-90dBc / Hz@1kHz (f3~f4)

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A de-skewed broadband frequency source, characterized in that, include: Reference source P1, power divider amplifier circuit U1, point frequency source P2, broadband linear frequency modulation waveform generation circuit U2, transceiver switch S1, frequency source P3, frequency source P4, mixer module U3, mixer module U4, wherein: The output of reference source P1 is connected to the input of the power divider amplifier circuit; the output of the power divider amplifier circuit U1 serves as the reference input signal for point frequency source P2, frequency source P3, and frequency source P4, respectively; the output of point frequency source P2 is connected to the input of the broadband linear frequency modulation waveform generation circuit U2; the output of the broadband linear frequency modulation waveform generation circuit U2 is connected to the input of the transceiver switch S1; the two outputs of the transceiver switch S1 are connected to the intermediate frequency inputs of the mixer module U3 and the mixer module U4, respectively; the output of frequency source P3 is connected to the local oscillator input of the mixer module U3; the output of frequency source P4 is connected to the local oscillator input of the mixer module U4; the output signal of the mixer module U3 is output to the transmitter as the excitation signal for radar transmission. The output signal of the mixer module U4 is output to the radar receiver front end as a local oscillator signal of the radar receiver; Within one radar repetition cycle, the frequency source generates a broadband baseband signal based on the transmit excitation trigger signal and switches the transceiver switch S1 to the channel connecting S1 and the mixer module U3. The broadband baseband signal is then output after being mixed and amplified by the mixer module U3 to provide the transmit excitation signal for the radar transmitter. When the radar receives the echo signal, it sends a local oscillator trigger control signal to the frequency source. The frequency source generates a broadband baseband signal based on this signal and switches the transceiver switch S1 to the channel connecting S1 and the mixer module U4. The broadband baseband signal is then output after being mixed and amplified by the mixer module U4 to provide the de-skewing local oscillator signal for the radar receiver.

2. The de-skewed broadband frequency source according to claim 1, characterized in that, The work process is as follows: The reference source P1 generates a reference clock signal with a frequency of 100 MHz; the power division amplification circuit U1 outputs the signal from the reference source P1 to the point frequency source P2, the frequency source P3 and the frequency source P4 respectively after power division amplification; the point frequency source P2 adopts an analog phase-locked dielectric oscillator, and outputs a point frequency signal with a frequency of f c as an input reference clock signal of the wideband linear frequency modulation waveform generation circuit U2; the wideband linear frequency modulation waveform generation circuit U2 is a wideband pulse waveform generation circuit based on DDS, and provides a wideband linear frequency modulation signal with a frequency range of f1~f2, where f1 and f2 refer to frequencies; the transceiving switch S1 is used for switching between a transmitting channel and a local oscillator signal channel, and the local oscillator needs to be generated within a time period occupied by a target echo; the frequency source P3 and the frequency source P4 are composed of a multi-path point frequency source and a switch assembly, and provide local oscillator signals for the mixing modules U3 and U4 respectively; the mixing module U3 is used for up-converting the f1~f2 wideband linear frequency modulation signal to a signal with a frequency of f3~f4, and provides an excitation signal for a radar transmitter, where f3 and f4 refer to frequencies; the mixing module U4 is used for up-converting the f1~f2 wideband linear frequency modulation signal to a signal with a frequency of f5~f6, and provides a desquaring signal for a radar receiver local oscillator, where f5 and f6 refer to frequencies.

3. The de-skewed broadband frequency source according to claim 1, characterized in that, The reference source P1 uses a 100MHz low-phase-noise temperature-controlled crystal oscillator with a frequency setting accuracy better than 3×10⁻⁶. -7 Spurious emissions are better than -70dBc, and phase noise is better than -165dBc / Hz@1kHz.

4. The de-skewed broadband frequency source according to claim 1, characterized in that, The broadband linear frequency modulation waveform generation circuit U2 outputs a broadband linear frequency modulation signal with a minimum frequency step of 1MHz and a signal bandwidth of 1.7GHz.

5. The de-skewed broadband frequency source according to claim 4, characterized in that, The broadband linear frequency modulation waveform generation circuit U2 adopts multi-channel parallel DDS technology to effectively increase the operating clock frequency of the DDS, thereby expanding the output bandwidth of the DDS.

6. The de-skewed broadband frequency source according to claim 1, characterized in that, In imaging mode, a transmission signal bandwidth of 1.7 GHz is used, with a maximum target imaging distance of better than 175 m and a target imaging resolution of less than 0.2 m.

Images