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A DSB demodulation method for canceling frequency offset

A demodulation method and frequency offset technology, applied in the field of DSB demodulation to offset frequency offset, can solve problems such as signal distortion, achieve amplitude stability, and improve demodulation signal-to-noise ratio

Active Publication Date: 2018-12-21
BEIJING BBEF SCI & TECH
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Problems solved by technology

[0016] The baseband signal is obtained by filtering out high-frequency components through a low-pass filter with a cutoff frequency of Ω Therefore, the demodulated signal adds a Modulate the signal, causing signal distortion

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  • A DSB demodulation method for canceling frequency offset
  • A DSB demodulation method for canceling frequency offset
  • A DSB demodulation method for canceling frequency offset

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Embodiment Construction

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0032] Such as figure 2 As shown, a DSB demodulation method for offsetting frequency offset includes the following steps:

[0033] The first step is to generate a local oscillator signal according to the frequency of the carrier signal at the sending end, and the local oscillator signal and the carrier signal have the same frequency;

[0034] The second step is to add a fixed "pre-frequency offset" signal to the local oscillator signal generated in the first step to generate a new local oscillator signal;

[0035] The third step, the new local oscillator signal and the received DSB signal are multiplied and demodulated to obtain the baseband signal with frequency offset and the secondary carrier high frequency signal;

[0036] The fourth step, using a digital low-pass filter to filter out the secondary car...

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Abstract

The invention discloses a DSB demodulation method for canceling frequency offset, which comprises the following steps: generating a cost vibration signal according to the frequency of a carrier signalof a transmitting terminal; a new local oscillator signal is generated by adding a fixed pre-frequency offset signal to the local oscillator signal. The new local oscillator signal is multiplied anddemodulated with the received DSB signal to obtain the baseband signal with frequency offset and the secondary carrier high frequency signal. Using a digital low-pass filter to filter out the secondary carrier high-frequency signal; generating a local pre-frequency offset signal at the same frequency as the aforementioned fixed pre-frequency offset signal. The band frequency offset baseband signalis multiplied by a fixed pre-frequency offset signal to obtain a clean baseband signal and a secondary pre-frequency offset signal; and the band frequency offset baseband signal is multiplied by a fixed pre-frequency offset signal to obtain a clean baseband signal and a secondary pre-frequency offset signal. A digital low-pass filter is used to filter out the secondary pre-frequency offset signal. The invention can well solve the influence of frequency offset in DSB demodulation, stabilize the amplitude of the demodulated baseband signal, and improve the demodulation signal-to-noise ratio.

Description

technical field [0001] The invention relates to the field, in particular to a DSB demodulation method for canceling frequency offset. Background technique [0002] Demodulation is the process of recovering a message from a modulated signal that carries it. In various information transmission or processing systems, the sender modulates the carrier wave with the message to be transmitted to generate a signal carrying the message. The receiving end must recover the transmitted message before it can be used, which is demodulation. [0003] At present, the commonly used demodulation method is to use the same frequency method of the local oscillator and the carrier for demodulation, that is, the DSB demodulation method. Its principle block diagram is as follows: figure 1 shown. Among them, if the received DSB signal is: [0004] u DSB (t) = cos Ω t cos w c t [0005] The local LO signal is: [0006] c(t)=cos w c t [0007] The signal output by the multiplier is: [0008...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/00
CPCH04L27/0014H04L2027/0026
Inventor 张守忠高肖霞李佳佳付欣李学军
Owner BEIJING BBEF SCI & TECH
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