Method and device for extracting local oscillation from wideband carrier

Abstract

The invention discloses a method for extracting local oscillation from a wideband carrier, which comprises the following steps that: a received carrier signal is subjected to limiting amplification to serve as a local oscillation signal of a quadrature modulator for input, and an intermediate frequency signal output by a local intermediate frequency source is decomposed into two paths of orthogonal baseband signals to serve as I and Q signals of the quadrature modulator for input; and the quadrature modulator utilizes the single-sideband modulation characteristic thereof to extract a local oscillation signal Fc-IF or Fc+IF modulated by a single sideband from a carrier. A device for extracting local oscillation from the wideband carrier comprises a local intermediate frequency (IF) source,a limiting amplification circuit, an intermediate frequency signal decomposition circuit and the quadrature modulator; a signal which is output after the carrier signal passes through the limiting amplification circuit is sent into a local oscillation signal input end of the quadrature modulator, the two paths of the orthogonal baseband signals which are acquired after the intermediate frequency signal produced by the intermediate frequency (IF) source passes through the intermediate frequency signal decomposition circuit are input into I and Q signal input ends of the quadrature modulator respectively, and the quadrature modulator outputs the needed local oscillation signal. The method and the device can effectively extract the local oscillation frequency without a bandpass filter withinthe frequency range of wideband radiofrequency carrier.

Description

technical field [0001] The invention relates to the field of signal processing in the field of electronics and communication, and is a method and device for extracting a local oscillator from a radio frequency carrier, which is suitable for the application range of broadband radio frequency carrier frequency. Background technique [0002] In wireless communication, only by tracking and locking the opponent's radar signal can the opponent's radar signal be effectively received and the signal parameters analyzed. Modern radio signal receivers generally adopt the superheterodyne form. The superheterodyne form receiver mixes the received radio signal with the local oscillator frequency, converts the signal to a fixed intermediate frequency, and then filters, amplifies and detects the intermediate frequency. The advantages of high sensitivity and good selectivity. figure 1 It is a superheterodyne receiving frequency conversion block diagram. The frequency of the local oscillato...

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Problems solved by technology

[0003] The problem to be solved by the present invention is: adopt the method of mixing carrier frequency and local intermediate frequency frequency source to extract the local oscillator frequency from the carrier, need to select the local oscillator frequency that wants to extract with band-pass filter, band-pass filter limits If the applicable carrier frequency bandwidth is not used, other frequency products of the mixing output, especially the carrier frequency leakage and image frequency will cause serious interference to the application of the local oscillator frequency, so that it cannot be used normally.

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