CN115372697A - Broadband instantaneous frequency measurement method and equipment based on single-bit reception - Google Patents

Abstract

The invention provides a broadband instantaneous frequency measurement method and equipment based on single-bit receiving, wherein the method directly samples radio frequency signals through a super-high-speed single-bit ADC with a sampling rate of 40Gsps, and the instantaneous frequency measurement of signals from 0.1GHz to 18GHz is realized through an instantaneous frequency measurement method. The invention realizes the broadband instantaneous frequency measurement through the time domain correlation detection technology, has the advantages of low computation complexity, wide instantaneous bandwidth and the like, and has strong universality and engineering realizability.

Description

Broadband instantaneous frequency measurement method and equipment based on single-bit reception

Technical Field

The present invention relates to digital signal processing, and more particularly, to a wideband instantaneous frequency measurement method and apparatus based on single-bit reception.

Background

The frequency is the main characterization parameter of the electromagnetic wave signal, and with the continuous development of the electronic warfare technology and the radar technology, the radar signal develops towards higher frequency and wider frequency band. In order to adapt to the complex electromagnetic environment of modern war, the instantaneous frequency measurement technology is widely applied to the field of electronic warfare. In order to ensure undistorted conversion of an analog signal into a digital signal by a conventional frequency measurement receiver, a radio frequency signal needs to be subjected to down-conversion first, and then a frequency-converted intermediate frequency signal needs to be sampled and processed, so that the sampling rate of an analog-to-digital conversion chip (ADC) is limited, and the instantaneous bandwidth of the receiver is not higher than half of the sampling rate, so that the instantaneous frequency measurement bandwidth is limited. With the continuous improvement of the level of electronic devices, the sampling rate of a single-bit ADC is higher and higher, and the direct sampling and processing of radio frequency signals can be realized. However, the ultrahigh sampling rate brings more processing pressure to the digital signal processing chip at the back end, and for the single-bit ADC with the ultrahigh sampling rate, the currently common signal instantaneous frequency measurement methods include a time domain frequency measurement method taking delay correlation calculation as a core and a frequency domain algorithm of simplified Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT). The time domain frequency measurement method has the advantages of low calculation complexity, resource saving, poor noise resistance, multiple signal processing capabilities, large calculation amount, difficulty in matching the signal sampling rate with the data transmission rate and high engineering realization difficulty.

Disclosure of Invention

The present invention aims to provide a wideband instantaneous frequency measurement method and device based on single-bit reception, which perform differential calculation on the instantaneous phase and resolve the phase difference ambiguity, so as to obtain the instantaneous frequency of the sampling signal.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a broadband instantaneous frequency measurement method based on single-bit reception, which comprises the following steps:

s1, a wireless and microwave component completes the receiving processing of radio frequency signals, and generates sampling signals to be output to an FPGA after single-bit high-speed ADC sampling;

s2, after receiving the N-point sampling signals, the FPGA performs circular correlation calculation on the sampling signals;

s3, performing Hilbert transformation on the sequence after the cyclic correlation calculation to obtain a real part I (k) and an imaginary part Q (k) of the transformed sequence;

s4, calculating an instantaneous phase sequence;

s5, carrying out differential calculation on the instantaneous phase sequence and resolving phase ambiguity;

s6, carrying out mean value statistics;

and S7, calculating instantaneous frequency.

Further, in S2, the cyclic correlation calculation performed on the sampling signal is as follows:

wherein S (k) is a cyclic correlation result; n is the total number of sampling points; i is the sequence number of sampling points; s (i) is an original sampling signal; s _k (i) The original sampled signal is circularly shifted by k points to the right.

Further, in S4, the method for calculating the instantaneous phase sequence Φ (k) includes:

further, in S4, a calculation method for performing difference calculation on the instantaneous phase sequence and resolving the phase ambiguity includes:

if φ (k + 1) - φ (k) ≧ π, Δ φ (k) = φ (k + 1) - φ (k) -2 π

If φ (k + 1) - φ (k) ≦ - π, Δ φ (k) = φ (k + 1) - φ (k) +2 π

If- π < φ (k + 1) - φ (k) < π, Δ φ (k) = φ (k + 1) - φ (k)

Where Δ φ (k) is the phase difference calculation result of φ (k).

Further, in S6, the mean value statistics method includes:

further, in S7, the instantaneous frequency is calculated by:

wherein f is the instantaneous frequency calculation result, f _s Is the sampling rate.

In addition, the broadband instantaneous frequency measurement device based on the single-bit reception is used for realizing the broadband instantaneous frequency measurement method based on the single-bit reception.

Further, it comprises:

an antenna: the device is used for receiving radio frequency signals and converting the received electromagnetic wave signals into electric signals;

a microwave assembly: the low noise amplifier, the band-pass filter and the amplifier are included;

the input end of the low-noise amplifier is connected with the antenna;

the output end of the low-noise amplifier is connected with the input end of the band-pass filter so as to realize low-noise amplification of signals;

the band-pass filter performs band-pass filtering on the signal after low-noise amplification;

the amplifier amplifies the filtered signal and converts the amplified signal into a radio frequency output signal.

Further, the method also comprises the following steps:

a digital component: the single-bit ADC and the FPGA comprise 40 Gsps;

the input end of the 40Gsps single-bit ADC is connected with the output end of the amplifier, and the radio frequency output signal is subjected to analog-to-digital conversion to output a sampling signal;

and the FPGA receives the sampling signal of the 40Gsps single-bit ADC and carries out frequency measurement, and finally, a frequency measurement result is output.

The beneficial effects of the invention are as follows: according to the method, the instantaneous frequency of the sampling signal is obtained by directly sampling the 0.1GHz to 18GHz signal, calculating the instantaneous phase of the sampling signal through time domain processing, carrying out differential calculation on the instantaneous phase and resolving phase difference ambiguity, and the method has the advantages of wide instantaneous bandwidth, strong noise resistance, low calculation complexity, high realizability and the like.

Drawings

FIG. 1 is a block diagram of a wideband instantaneous frequency measurement device based on single-bit reception according to the present invention;

fig. 2 is a process of frequency measurement data processing according to the first embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

Please refer to, a wideband instantaneous frequency measurement method based on single-bit reception, comprising the following steps:

s1, a wireless and microwave component completes receiving processing of radio frequency signals, and generates sampling signals to be output to an FPGA after single-bit high-speed ADC sampling;

s2, after receiving the N-point sampling signals, the FPGA performs circular correlation calculation on the sampling signals;

s3, performing Hilbert transformation on the sequence after the cyclic correlation calculation to obtain a real part I (k) and an imaginary part Q (k) of the transformed sequence;

s4, calculating an instantaneous phase sequence;

s5, carrying out differential calculation on the instantaneous phase sequence and solving phase ambiguity;

s6, carrying out mean value statistics;

and S7, calculating instantaneous frequency.

In S2, performing cyclic correlation calculation on the sampling signal includes:

wherein S (k) is a cyclic correlation result; n is the total number of sampling points; i is the sequence number of sampling points; s (i) is an original sampling signal; s _k (i) The original sampled signal is circularly shifted by k points to the right.

In S4, the method for calculating the instantaneous phase sequence Φ (k) includes:

in S4, the calculation method for performing difference calculation on the instantaneous phase sequence and resolving the phase ambiguity includes:

if φ (k + 1) - φ (k) ≧ π, Δ φ (k) = φ (k + 1) - φ (k) -2 π

If φ (k + 1) - φ (k) is less than or equal to- π, Δ φ (k) = φ (k + 1) - φ (k) +2 π

If- π < φ (k + 1) - φ (k) < π, Δ φ (k) = φ (k + 1) - φ (k)

Where Δ φ (k) is the phase difference calculation result of φ (k).

In S6, the method for mean value statistics includes:

in S7, the instantaneous frequency calculation method includes:

wherein f is the instantaneous frequency calculation result, f _s Is the sampling rate.

As shown in fig. 1, a wideband instantaneous frequency measurement device based on single-bit reception includes:

antenna 1: the device is used for receiving radio frequency signals and converting the received electromagnetic wave signals into electric signals;

a microwave assembly: comprises a low noise amplifier 201, a band-pass filter 202 and an amplifier 203;

the input end of the low noise amplifier 201 is connected with the antenna 1;

the output end of the low noise amplifier 201 is connected with the input end of the band-pass filter 202 to realize low noise amplification of signals;

the band-pass filter 202 performs band-pass filtering on the signal after low-noise amplification;

the amplifier 203 amplifies the filtered signal and converts the amplified signal into a radio frequency output signal.

A wideband instantaneous frequency measurement device based on single bit reception, further comprising:

digital components: the single-bit ADC3 and the FPGA4 comprise 40 Gsps;

the input end of the 40Gsps single-bit ADC is connected with the output end of the amplifier, and analog-to-digital conversion is carried out on a radio frequency output signal to output a sampling signal;

and the FPGA receives the sampling signal of the 40Gsps single-bit ADC and carries out frequency measurement, and finally, a frequency measurement result is output.

A broadband instantaneous frequency measurement device based on single bit reception mainly comprises: antenna, microwave component, digital component and power supply component. The antenna mainly receives radio frequency signals and converts the received electromagnetic wave signals into electric signals.

The microwave component comprises a low-noise amplifier, a band-pass filter and an amplifier, wherein the input end of the low-noise amplifier is connected with the antenna, and the output end of the low-noise amplifier is connected with the input end of the band-pass filter, so that the low-noise amplification of signals is realized; the band-pass filter performs band-pass filtering on the signal after low-noise amplification; the amplifier amplifies the filtered signal and converts the amplified signal into a radio frequency output signal.

The digital assembly comprises a 40Gsps single-bit ADC and an FPGA, wherein the input end of the 40Gsps single-bit ADC is connected with the output end of the amplifier, and the radio frequency output signal is subjected to analog-to-digital conversion to output a sampling signal; and the FPGA receives the sampling signal of the single-bit ADC, performs frequency measurement and finally outputs a frequency measurement result. The power supply assembly provides a direct current power supply for the microwave assembly and the digital assembly to work normally.

Example one

Referring to fig. 2, a wideband instantaneous frequency measurement method based on single-bit reception, for a 100MHz signal, the frequency measurement process flow is as follows: the radio frequency output data of the 100MHz radio frequency signal s (t) after the band-pass filtering and the amplification is subjected to the sampling rate f _s Sampling a single-bit ADC (analog to digital converter) with the sampling rate of =40Gsps to obtain single-bit sampling data s (n), performing cyclic correlation processing on the single-bit sampling data to obtain a cyclic correlation calculation result s (k), performing Hilbert conversion to obtain a real part I (k) and an imaginary part Q (k) of Hilbert conversion, calculating an instantaneous phase phi (k) of the Hilbert conversion result, performing phase difference calculation and resolving phase ambiguity delta phi (k), and counting a mean value to obtain a result

Instantaneous frequency calculation result

The above-mentioned embodiments only express the embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be defined by the appended claims.

Claims (9)

1. A broadband instantaneous frequency measurement method based on single-bit reception is characterized by comprising the following steps:

s1, a wireless and microwave component completes the receiving processing of radio frequency signals, and generates sampling signals to be output to an FPGA after single-bit high-speed ADC sampling;

s2, after receiving the N-point sampling signals, the FPGA performs circular correlation calculation on the sampling signals;

s3, performing Hilbert transform on the sequence after the cyclic correlation calculation to obtain a real part I (k) and an imaginary part Q (k) of the transformed sequence;

s4, calculating an instantaneous phase sequence;

s5, carrying out differential calculation on the instantaneous phase sequence and resolving phase ambiguity;

s6, carrying out mean value statistics;

and S7, calculating instantaneous frequency.

2. A wideband instantaneous frequency measurement method based on single-bit reception according to claim 1, characterized in that: in S2, the cyclic correlation calculation of the sampling signal is as follows:

wherein S (k) is a cyclic correlation result; n is the total number of sampling points; i is the sequence number of sampling points; s (i) is an original sampling signal; s _k (i) The original sampled signal is circularly shifted by k points to the right.

3. The wideband instantaneous frequency measurement method based on single-bit reception according to claim 2, wherein in S4, the instantaneous phase sequence Φ (k) is calculated by:

4. the wideband instantaneous frequency measurement method based on single-bit reception according to claim 3, wherein in S4, the calculation method for performing difference calculation on the instantaneous phase sequence and resolving the phase ambiguity includes:

if φ (k + 1) - φ (k) ≧ π, Δ φ (k) = φ (k + 1) - φ (k) -2 π

If φ (k + 1) - φ (k) ≦ - π, Δ φ (k) = φ (k + 1) - φ (k) +2 π

If- π < φ (k + 1) - φ (k) < π, Δ φ (k) = φ (k + 1) - φ (k)

Where Δ φ (k) is the phase difference calculation result of φ (k).

5. The method of claim 4, wherein in S6, the method of mean value statistics is as follows:

6. the wideband instantaneous frequency measurement method based on single-bit reception according to claim 5, wherein in S7, the instantaneous frequency is calculated by:

wherein f is the instantaneous frequency calculation result, f _s Is the sampling rate.

7. A wideband instantaneous frequency measurement device based on single-bit reception, which is used for implementing the wideband instantaneous frequency measurement method based on single-bit reception as claimed in any one of claims 1 to 6.

8. A wideband instantaneous frequency measurement device based on single-bit reception according to claim 7, characterized by comprising:

an antenna: the device is used for receiving radio frequency signals and converting the received electromagnetic wave signals into electric signals;

a microwave assembly: the low-noise amplifier, the band-pass filter and the amplifier are included;

the input end of the low noise amplifier is connected with the antenna;

the output end of the low-noise amplifier is connected with the input end of the band-pass filter so as to realize low-noise amplification of signals;

the band-pass filter performs band-pass filtering on the signal after low-noise amplification;

the amplifier amplifies the filtered signal and converts the amplified signal into a radio frequency output signal.

9. The wideband instantaneous frequency measurement device based on single-bit reception according to claim 8, characterized by further comprising:

digital components: the single-bit ADC comprises 40Gsps and an FPGA;

the input end of the 40Gsps single-bit ADC is connected with the output end of the amplifier, and analog-to-digital conversion is carried out on a radio frequency output signal to output a sampling signal;

and the FPGA receives the sampling signal of the 40Gsps single-bit ADC and carries out frequency measurement, and finally, a frequency measurement result is output.

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