Frequency modulation (FM) Doppler distance measurement signal processing device

Abstract

The invention relates to a frequency modulation (FM) Doppler distance measurement signal processing device, which comprises a high frequency active band-pass filter, a low frequency active band-pass filter, a double mixer, two automatic gain amplifiers, two diode envelope detectors and a single chip microcomputer. The working principle of the FM Doppler distance measurement signal processing device is that difference frequency signals with distance information respectively output second harmonic and fourth harmonic to the double mixer after filtering through the two active band-pass filters, the double mixer mixes the second harmonic and the fourth harmonic respectively with local oscillating signals input from the single chip microcomputer to output two-way sine wave signals, the two sine wave signals are then respectively subjected to gain of the automatic gain amplifiers and envelope detection of the diode envelope detectors, two-way envelope signals containing distance information are obtained and output to the single chip microcomputer, the single chip microcomputer carries out comparison operation for the input two-way envelope signals and judges whether to start detonating signals according to the obtained results. The FM Doppler distance measurement signal processing device has the advantages of being good in distance cut-off characteristics, strong in capacity of resisting disturbance, high in reliability of distance determination and the like.

Description

technical field [0001] The invention relates to a frequency modulation radio fuze, in particular to a frequency modulation Doppler ranging signal processing device based on a frequency modulation ranging system. Background technique [0002] FM radio fuze is a constant-amplitude continuous-wave radio fuze whose transmission signal frequency changes according to the regulation of the modulation signal. The explosion point of the fuze has nothing to do with the target’s reflection characteristics of electromagnetic waves, and it has good distance selection ability, so its research has great significance. important theoretical and practical significance. [0003] The general FM ranging system mainly determines the target distance by measuring the frequency of the difference frequency. The frequency of the transmitted signal of the FM system is a function of time. During the period when the radio signal is launched from the fuze and returns to the target, the transmitted signal...

AI Technical Summary

Problems solved by technology

Because there are some irregular areas in the difference frequency, in these irregular intervals, the difference frequency cannot be obtained by the difference frequency formula, and they have no direct relationship with the distance, and the difference frequency changes periodically according to a certain law over time, which is very Obviously, the frequency spectrum of the periodic signal is discrete, so the difference frequency is also discrete. Therefore, the distance measurement of the general FM ranging system is not very accurate.

In addition, the above-mentioned difference frequency analysis method does not consider the relative motion between the FM ranging system and the target, and also ignores the influence of Doppler, and the time-frequency method uses the direct subtraction of the transmitting frequency and the receiving frequency, but in practice Mixing should be phase subtractive

Therefore, this difference frequency analysis method is approximate, and the distance measured by this frequency modulation ranging system is also an approximate result, which cannot meet the higher precision fuze distance determination requirements

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