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Method of demodulation of stereophonic signal

A demodulation method, stereo technology, applied in the direction of stereo broadcast reception, broadcast receiving circuit, electrical components, etc., can solve the problems of complex extraction of pilot signals, problems, inability to fully attenuate the amplitude and restore the difference signal, etc., to improve the total harmonic The effect of wave distortion

Active Publication Date: 2021-06-18
CONTINENTAL AUTOMOTIVE FRANCE +1
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The demodulation of the stereo signal may have been limited due to the complicated extraction of the pilot signal on the one hand and the use of various filters which degrade the total harmonic distortion and the left / right channel separation on the other hand. Proof is tricky, even problematic
This is especially true when the energy of the sum signal is higher than that of the difference signal, the known demodulation methods cannot sufficiently attenuate the amplitude of the sum signal to properly restore (récupérer) the difference signal

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  • Method of demodulation of stereophonic signal
  • Method of demodulation of stereophonic signal
  • Method of demodulation of stereophonic signal

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Embodiment Construction

[0024] The object of the present invention is a demodulation method, which is particularly suitable for figure 1 signal S(f) shown. Signal S(f) is a multiplexed stereo signal. The invention also aims at an apparatus for implementing the demodulation method. The device is preferably a car radio system for a motor vehicle, and in particular a system configured to receive FM channels.

[0025] The signal S(f) includes a first signal called the sum signal, which is in the first frequency band and is the sum of two mono signals, denoted G and D (for left and right) . like figure 1 It can be seen that the sum signal is represented by the symbol G+D.

[0026] The signal S(f) also includes a second signal, called the difference signal, which is in the second frequency band and is the difference between the two mono signals G and D. like figure 1 It can be seen that the difference signal is represented by the symbol G-D.

[0027] The difference signal has been modulated by a ca...

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Abstract

The subject of the invention is a method of demodulation of a multiplexed stereophonic signal (S(f)), the signal comprising a signal, termed sum signal (G+D), a signal, termed difference signal (G-D), and a pilot signal. The method comprises the following steps of eliminating the pilot frequency from the multiplexed stereophonic signal (S(f)), the resulting signal being called pilotless signal (S2(f)), and subtracting the sum signal (G+D) from the pilotless signal (S2(f)).

Description

technical field [0001] The present invention relates to a method for demodulating a multiplexed stereo signal, which method is implemented in particular by a car radio system for a motor vehicle, and in particular a system configured to receive FM channels. Background technique [0002] Such a stereo signal consists of a set of a first signal and a second signal, the first signal is called the sum signal, which is the sum of the two left and right mono signals; and the second signal is called the difference signal, which is the two The difference between the mono signals and has been modulated by a carrier wave of preferably 38 kHz. To generate this 38kHz carrier, the stereo signal also includes a pilot signal whose frequency is the frequency of the 38kHz carrier divided by two. [0003] Due to the complex extraction of the pilot signal on the one hand, and on the other hand due to the use of various filters which degrade the total harmonic distortion rate and the left / righ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/16H04H40/45
CPCH04B1/1653H04H40/45H04B1/1646H04B1/1676
Inventor G·苏利耶
Owner CONTINENTAL AUTOMOTIVE FRANCE