ASK (Amplitude Shift Keying) fast demodulation method based on secondary radar

Abstract

The invention provides an ASK (Amplitude Shift Keying) fast demodulation method based on secondary radar. The method comprises the following steps: approximating an envelope of an A / D (Analog to Digital) sampling signal into a sinusoidal signal, wherein the frequency is f<o>; performing delaying by using the characteristic of the sinusoidal signal to obtain an I-path signal and a Q-path signal being orthogonal to each other; getting a root mean square to obtain amplitude information; and outputting demodulated ASK information. Compared with an ASK demodulation method in the prior art, the ASKfast demodulation method provided by the invention has the advantage that a demodulated ASK baseband signal can be output in a shorter time. The method can be used for judging the presence of P4 pulses in an interrogation signal by an S-mode responder, and meets the requirement of the S-mode responder on response delay in a conventional mode.

Description

technical field [0001] The invention relates to an ASK fast demodulation method based on secondary radar. Background technique [0002] The software radio receiver is mainly composed of a radio frequency front end, a wideband digital-to-analog / analog-to-digital converter, a digital front end and a high-speed digital signal processor. Among them, the digital front end demodulates the digital intermediate frequency signal after A / D sampling to obtain the baseband signal. In the existing secondary radar ASK demodulation algorithm, it is necessary to mix and filter the digital intermediate frequency signal after A / D sampling to obtain the baseband and then perform decoding operation, which causes the conventional mode response delay (conventional mode response The delay index requires 3±0.5us) to be greater than 3.5us, which does not meet the system design requirements. [0003] In the existing solution, when the software processing delay increases, the delay time of the hardw...

AI Technical Summary

Problems solved by technology

In the existing secondary radar ASK demodulation algorithm, it is necessary to mix and filter the digital intermediate frequency signal after A / D sampling to obtain the baseband and then perform decoding operation, which causes the conventional mode response delay (conventional mode response The delay index requires 3±0.5us) to be greater than 3.5us, which does not meet the system design requirements

[0003] In the existing solution, when the software processing delay increases, the delay time of the hardware channel can be compressed to meet the requirements of the S-mode transponder for the response delay of the conventional mode (the index of the response delay of the conventional mode requires 3 ± 0.5us ), it is necessary to improve the performance of the hardware, resulting in an increase in hardware cost

Images