hi 🙂
i m trying to generate a biphasic pulse train to modulate with speech signal. but all i found is pulse train with positive amplitude only.
how could I generate a biphasic pulse train ? any help ?
MATLAB: How could I generate a biphasic pulse train
digital signal processingsignal processing
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The answer is No! .I am not aware of any function which can do that for you. Try to adapt my function for your needs or write your own.
%Does this work for you?
[t,p]=Trapezoidal_pulse(1,3,0.01,1,1,5,8);figure,plot(t,p)The function:
%%
function [t,pulse_train]=Trapezoidal_pulse(Amplitude,FlatTopTime,DwellTime,RiseTime,FallTime,DeadTime,Repetitions)%[t,pulse_train]=Trapezoidal_pulse(Amplitude,FlatTopTime,DwellTime,RiseTime,FallTime,DeadTime,Repetitions)
% All times are of same units
% DwellTime-1/Sampling rate or raster time
% DeadTime- Dead Time after each pulse
%Repetitions -Number of Trapezoidal pulses
if(RiseTime<DwellTime) warn('RiseTime<DwellTime: No Ramp up samples') rampup_samples=[];else rampup_samples= linspace(0,Amplitude,ceil(RiseTime/DwellTime));endif(FallTime<DwellTime) warn('FallTime<DwellTime: No Ramp down samples') rampdown_samples=[];else rampdown_samples= linspace(Amplitude,0,ceil(FallTime/DwellTime));endpulse=[rampup_samples Amplitude*ones(1,ceil(FlatTopTime/DwellTime)) rampdown_samples zeros(1,ceil(DeadTime/DwellTime))];%bipolar
% pulse_train=repmat(pulse,[Repetitions 1]).'.*(-1*ones(length(pulse),1)).^(0:Repetitions-1);
%unipolar
pulse_train=repmat(pulse,[Repetitions 1]).';pulse_train=pulse_train(:);%time
t=(0:(length(pulse_train)-1))*DwellTime;endUse doc or edit command to see the ownership and year at which the function is added to matlab.
Is your signal stereo instead of monochannel? You need to take that into account.
See this little demo for mono, and adapt as needed:
% Initialization steps.
clc; % Clear the command window.
fprintf('Beginning to run %s.m ...\n', mfilename);close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format short g;format compact;fontSize = 15;% Read in the sound.
[y, Fs] = audioread('guitartune.wav');% load('handel.mat'); % Another sound you can load.
% Play the sound.
soundsc(y, Fs);% Compute the time axis
t = (1 : length(y)) / Fs;subplot(3, 1, 1);plot(t, y, 'b-', 'LineWidth', 2);title('Original Audio Waveform', 'FontSize', fontSize);xlabel('Seconds', 'FontSize', fontSize);ylabel('Amplitude', 'FontSize', fontSize);xticks(1 : round(t(end)));grid on;drawnow;audioTime = length(y) / Fs; % In seconds.
fprintf('Audio length = %.3f seconds.\n', audioTime);% Compute how many seconds 2 seconds is.
pulseWidth = Fs; % Whatever it needs to get 1 (half of 2) of whatever units you're using.
onePulse = [ones(1, pulseWidth), zeros(1, pulseWidth)];% Replicate as many times as we need (more actually)
numReps = ceil(audioTime/2);pulseTrain = repmat(onePulse, [1, numReps]);% Now crop down to the actual signal length that y is
pulseTrain = pulseTrain(1 : length(y));% Reshape to be a column vector like y
pulseTrain = pulseTrain(:);% Plot the pulse train.
subplot(3, 1, 2);plot(t, pulseTrain, 'b-', 'LineWidth', 2);title('Pulse Train', 'FontSize', fontSize);xlabel('Seconds', 'FontSize', fontSize);ylabel('Amplitude', 'FontSize', fontSize);grid on;xticks(1 : round(t(end)));% Multiple the pulse train by the audio signal and plot.
yPulsed = y .* pulseTrain;% Plot the pulse train.subplot(3, 1, 3);plot(t, yPulsed, 'b-', 'LineWidth', 2);title('Pulsed Waveform', 'FontSize', fontSize);xlabel('Seconds', 'FontSize', fontSize);ylabel('Amplitude', 'FontSize', fontSize);grid on;xticks(1 : round(t(end)));pause(audioTime);% Play the sound.soundsc(yPulsed, Fs);fprintf('Done running %s.m ...\n', mfilename);
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