CN213482447U

CN213482447U - Reflection pulse signal time delay measuring circuit

Info

Publication number: CN213482447U
Application number: CN202022130425.8U
Authority: CN
Inventors: 沙文祥; 王�锋; 钱张宏; 张燕
Original assignee: Nanjing Glarun Atten Technoogy Co ltd
Current assignee: Nanjing Glarun Atten Technoogy Co ltd
Priority date: 2020-09-24
Filing date: 2020-09-24
Publication date: 2021-06-18
Anticipated expiration: 2030-09-24

Abstract

The utility model discloses a reflection pulse signal time delay measurement circuit, the signal quadrature demodulation to launching wave and back wave respectively, obtain corresponding baseband signal, carry out the multiplication operation again, calculate the complex conjugate of launching wave and back wave, through the arctangent operation, divide by 2 pi fc, obtain the phase difference value delta T of launching wave and back wave, can calculate the time delay of reflection pulse signal fast, circuit structure is simple, the cost is lower, easily realize, real part and the imaginary part of utilizing quadrature signal separation launching wave and back wave, ingenious through the conjugate operation, obtain the phase difference value of launching wave and back wave, avoid the error, it is more accurate.

Description

Reflection pulse signal time delay measuring circuit

Technical Field

The utility model belongs to the technical field of electronic circuit, concretely relates to pulse signal circuit technique.

Background

The structure principle of the measuring device is shown in fig. 1, a signal source transmits a pulse signal to a measured object through a transmitting device, such as an antenna, an ultrasonic generator and the like, the pulse signal is received by a receiving device after being reflected by the measured object, the delay quantity delta T between the transmitted pulse and the reflected pulse is compared, and then the distance from the measured object to a measuring point can be calculated through a formula S-delta T-v according to the wave velocity v.

The simplest and most direct method for measuring the delay is to measure the time difference Δ T between the rising edges of two pulse signals, as shown in fig. 2, which is limited by the AD sampling clock and has a poor accuracy, usually only to milliseconds.

The current general method is to measure Δ T indirectly by measuring the phase difference Δ Φ between the transmitted and reflected pulse signals, and then calculate the distance S according to the frequency fc of the known pulse signal by the formula Δ T ═ Δ Φ/360/fc, at this time, the calculation of the phase difference is the key of the delay measurement.

The traditional phase difference calculation method is shown in fig. 3, and is characterized in that the FFT calculation of reflected wave pulse signals is carried out on the transmitted waves in the same time period to obtain amplitude-frequency data and phase-frequency data, the peak point of the amplitude-frequency data is found, the phase value corresponding to the peak point is found, and the difference is calculated to obtain the phase difference delta phi.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a solve the problem that prior art exists, provided a reflection pulse signal time delay measuring circuit, in order to realize above-mentioned purpose, the utility model discloses a following technical scheme.

The circuit comprises: the multiplier I, the multiplier II, the multiplier III, the multiplier IV, the low-pass filter I, the low-pass filter II, the orthogonal signal generator, the inverter, the complex multiplier, the phase discriminator and the fixed value multiplier; the first multiplier and the second multiplier are connected in parallel, the input end receives the transmitted wave, and the output end is connected with the input end of the first low-pass filter; the multiplier III is connected with the multiplier IV in parallel, the input end of the multiplier III receives the reflected wave, and the output end of the multiplier III is connected with the input end of the low-pass filter II; two paths of outputs of the first low-pass filter are connected with a complex multiplier, one path of output of the second low-pass filter is connected with the complex multiplier, and the other path of output is connected with the complex multiplier through an inverter; the complex multiplier is connected with the fixed value multiplier through the phase discriminator; one output of the orthogonal signal generator is connected with the input ends of the first multiplier and the third multiplier, and the other output of the orthogonal signal generator is connected with the input ends of the second multiplier and the fourth multiplier.

The orthogonal signal generator generates two orthogonal signals sin (wt) and cos (wt) with the same frequency fc as the carrier wave of the transmitting wave, and the cos (wt) is input into a first multiplier and a third multiplier, and the sin (wt) is input into a second multiplier and a fourth multiplier.

The low-pass filter I receives a multiplication result of cos (wt) and the transmitting wave, outputs a baseband signal P _ i as a real part signal of the transmitting wave, receives a multiplication result of sin (wt) and the transmitting wave, outputs a baseband signal P _ q as an imaginary part signal of the transmitting wave, and combines the P _ i and the P _ q into a transmitting wave signal P; and a second low-pass filter for receiving the multiplication result of cos (wt) and the reflected wave, outputting a baseband signal S _ i as a real part signal of the reflected wave, receiving the multiplication result of sin (wt) and the reflected wave, outputting a baseband signal S _ q as an imaginary part signal of the reflected wave, and combining S _ i and S _ q into a reflected wave signal S.

The complex multiplier receives the baseband signals P _ i, S _ i and P _ q and the baseband signal S _ q passing through the inverter and outputs the complex multiplication operation result of the transmitted wave and the reflected wave

And the phase discriminator receives the complex multiplication operation result and performs arc tangent operation.

And fixing a multiplier, wherein the coefficient is the reciprocal of 2 pi fc, receiving the arctangent operation result of the phase discriminator, performing division operation, and outputting the phase difference value delta T of the transmitted wave and the reflected wave.

The utility model discloses can calculate the time delay of reflection pulse signal fast, circuit structure is simple, and the cost is lower, easily realizes, utilizes the real part and the imaginary part of quadrature signal separation launching wave and back wave, ingenious through the conjugate operation, obtains the phase difference value of launching wave and back wave, avoids the error, and is more accurate.

Drawings

Fig. 1 is a schematic diagram of direct measurement, fig. 2 is a waveform diagram of the direct measurement principle, fig. 3 is a waveform diagram of the indirect measurement principle, fig. 4 is a schematic diagram of the present circuit, and fig. 5 is a waveform diagram of the present circuit principle.

Detailed Description

The technical scheme of the utility model is explained in detail with the attached drawings.

The circuit principle is as shown in fig. 4, the first multiplier and the second multiplier are connected in parallel, the input end receives the transmitted wave, and the output end is connected with the input end of the first low-pass filter; the multiplier III is connected with the multiplier IV in parallel, the input end of the multiplier III receives the reflected wave, and the output end of the multiplier III is connected with the input end of the low-pass filter II; two paths of outputs of the first low-pass filter are connected with a complex multiplier, one path of output of the second low-pass filter is connected with the complex multiplier, and the other path of output is connected with the complex multiplier through an inverter; the complex multiplier is connected with the fixed value multiplier through the phase discriminator; one output of the orthogonal signal generator is connected with the input ends of the first multiplier and the third multiplier, and the other output of the orthogonal signal generator is connected with the input ends of the second multiplier and the fourth multiplier.

Assuming that the transmitted wave carrier frequency is fc, the transmitted wave signal can be described as s (T) ═ cos (2 pi fct + phi), and the reflected wave signal is delayed and can be described as sc (T) ═ cos (2 pi fc × (T + Δ T) + phi).

The orthogonal signal generator generates two orthogonal signals sin (wt) and cos (wt) with the same frequency as the carrier wave of the transmitting wave, and the cos (wt) is input into a first multiplier and a third multiplier, and the sin (wt) is input into a second multiplier and a fourth multiplier.

The signals of the transmitted wave and the reflected wave are subjected to quadrature demodulation respectively to obtain corresponding baseband signals, wherein a transmitted wave baseband signal S '(T) ═ exp (j phi), a reflected wave baseband signal sc' (T) ═ exp (j × 2 pi fc × Δ T + j phi), j is a complex symbol, a real part of the transmitted wave baseband signal is P _ i, an imaginary part of the transmitted wave baseband signal is P _ q, a real part of the reflected wave baseband signal is S _ i, and an imaginary part of the reflected wave baseband signal is S _ q.

Computing

Is S_c(t) complex conjugation

A phase discriminator for receiving the complex multiplication result and performing an arctangent operation by setting r to cos (2 pi fc × Δ T) and i to sin (2 pi fc × Δ T) to obtain

A fixed multiplier with coefficient of 2 pi fc, receiving the inverse tangent result of phase discriminator, and dividing

Output shaftThe phase difference Δ T between the radio wave and the reflected wave.

The above-mentioned embodiments of the present invention are not intended to limit the present invention, and any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A reflected pulse signal delay measurement circuit, comprising: the multiplier I, the multiplier II, the multiplier III, the multiplier IV, the low-pass filter I, the low-pass filter II, the orthogonal signal generator, the inverter, the complex multiplier, the phase discriminator and the fixed value multiplier; the first multiplier and the second multiplier are connected in parallel, the input end receives the transmitted wave, and the output end is connected with the input end of the first low-pass filter; the multiplier III is connected with the multiplier IV in parallel, the input end of the multiplier III receives the reflected wave, and the output end of the multiplier III is connected with the input end of the low-pass filter II; two paths of outputs of the first low-pass filter are connected with a complex multiplier, one path of output of the second low-pass filter is connected with the complex multiplier, and the other path of output is connected with the complex multiplier through an inverter; the complex multiplier is connected with the fixed value multiplier through the phase discriminator; one output of the orthogonal signal generator is connected with the input ends of the first multiplier and the third multiplier, and the other output of the orthogonal signal generator is connected with the input ends of the second multiplier and the fourth multiplier.

2. The delay measurement circuit of claim 1, wherein the quadrature signal generator generates two orthogonal signals sin (wt) and cos (wt) having a frequency equal to the frequency fc of the transmitted carrier, and the cos (wt) is input to the first multiplier and the third multiplier, and the sin (wt) is input to the second multiplier and the fourth multiplier.

3. The delay measuring circuit of claim 2, wherein the first low pass filter receives the multiplication result of cos (wt) and the transmission wave, outputs a baseband signal P _ i as the real part signal of the transmission wave, receives the multiplication result of sin (wt) and the transmission wave, outputs a baseband signal P _ q as the imaginary part signal of the transmission wave, and combines P _ i and P _ q into the transmission wave signal P; and the second low-pass filter receives the multiplication result of cos (wt) and the reflected wave, outputs a baseband signal S _ i as a real part signal of the reflected wave, receives the multiplication result of sin (wt) and the reflected wave, outputs a baseband signal S _ q as an imaginary part signal of the reflected wave, and combines the S _ i and the S _ q into a reflected wave signal S.

4. The delay measurement circuit of claim 3, wherein the complex multiplier receives the baseband signals P _ i, S _ i, P _ q and the baseband signal S _ q via the inverter, and outputs a result of complex multiplication of the transmitted wave and the reflected wave

5. The reflected pulse signal delay measurement circuit of claim 1, wherein the phase detector receives the complex multiplication result and performs an arc tangent operation.

6. The delay measurement circuit of claim 1, wherein the fixed value multiplier receives the inverse of 2 pi fc and the inverse tangent operation result of the phase detector, performs division operation, and outputs the phase difference Δ T between the transmitted wave and the reflected wave.