DTMF dual tone multi frequency signal simulation demonstration system

1 brief introduction

Introduce DTMF Principle of signal generation and detection , Use Matlab Analog DTMF signal (DTMF) As a kind of user signaling, it is used in the signal transmission process between the telephone and the switch in the telephone system . stay Matlab The simulation is helpful to the optimization design of its specific system and signal detection in low noise environment .​

2 Part of the code

function[t,st]=lpf(f,sf,B)%  low pass filter df=f(2)-f(1);fN=length(f);ym=zeros(1,fN);xm=floor(B/df);xm_shift=[-xm:xm-1]+floor(fN/2);ym(xm_shift)=1;yf=ym.*sf;[t,st]=F2T(f,yf);

3 Simulation results

4 reference

[1] Zhang Yaqi . be based on Matlab Analog multi tone signal [J]. Information and computers ： Theory Edition , 2013(6):2.

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