MATLAB: DTMF tone using matlab

dtmf

can anyone tell me how to implement DTMF tone using matlab and i have to listen the tone

Best Answer

symbol = {'1','2','3','4','5','6','7','8','9','*','0','#'};
lfg = [697 770 852 941]; % Low frequency group
hfg = [1209 1336 1477];  % High frequency group
f  = [];
for c=1:4,
    for r=1:3,
        f = [ f [lfg(c);hfg(r)] ];
    end
end
Fs  = 8000;       % Sampling frequency 8 kHz
N = 800;          % Tones of 100 ms
t   = (0:N-1)/Fs; % 800 samples at Fs
pit = 2*pi*t;
tones = zeros(N,size(f,2));
for toneChoice=1:12,
    % Generate tone
    tones(:,toneChoice) = sum(sin(f(:,toneChoice)*pit))';
    % Plot tone
    subplot(4,3,toneChoice),plot(t*1e3,tones(:,toneChoice));
    title(['Symbol "', symbol{toneChoice},'": [',num2str(f(1,toneChoice)),',',num2str(f(2,toneChoice)),']'])
    set(gca, 'Xlim', [0 25]);
    ylabel('Amplitude');
    if toneChoice>9, xlabel('Time (ms)'); end
end
set(gcf, 'Color', [1 1 1], 'Position', [1 1 1280 1024])
annotation(gcf,'textbox', 'Position',[0.38 0.96 0.45 0.026],...
    'EdgeColor',[1 1 1],...
    'String', '\bf Time response of each tone of the telephone pad', ...
    'FitBoxToText','on');

Related Solutions

MATLAB: Need help for DTMF Scoring fucntion

I wouldn't write it like this because the dtmfscor function needs to know which column of tones it needs. But if you call the following:

>>[tones,ss] = dtmfking;
function [tones,ss] = dtmfking
lfg = [697 770 852 941]; % Low frequency group
hfg = [1209 1336 1477];  % High frequency group
% construct table of frequencies
f  = [];
for c=1:4,
    for r=1:3,
        f = [ f [lfg(c);hfg(r)] ];
    end
end
Fs  = 8000;       % Sampling frequency 8 kHz
N = 800;          % Tones of 100 ms
t   = (0:N-1)/Fs; % 800 samples at Fs
pit = 2*pi*t;
tones = zeros(N,size(f,12));
for toneChoice=1:12,
    % Generate tone
    tones(:,toneChoice) = sum(sin(f(:,toneChoice)*pit))';
end
ss = dtmfscor(tones,697,20,8000);
%Here i am giving the first freq and first column to cross check
function ss = dtmfscor(tones, freq, L, fs) 
if (nargin < 4), fs = 8000; end; 
hh = (2/L)*cos(2*pi*freq*(0:L-1)/fs); 
ss = (mean(conv(tones(:,1),hh).^2) > mean(tones(:,1).^2)/5);
end
end

MATLAB: DTFM decoding using goertzel algorithm and peak-picking

I figured it out. It came down to a garbage in garbage out problem. My tone generation was bad. I wound up using this code instead, it is mostly an implementation of snippets from the 'dtmfdemo' code.

symbol = {'1','2','3','4','5','6','7','8','9','*','0','#'};
lfg = [697 770 852 941]; % Low frequency group
hfg = [1209 1336 1477];  % High frequency group
f  = [];
for c=1:4,
    for r=1:3,
        f = [ f [lfg(c);hfg(r)] ];
    end
end
Fs  = 8000;       % Sampling frequency 8 kHz
N = 800;          % Tones of 100 ms
t   = (0:N-1)/Fs; % 800 samples at Fs
pit = 2*pi*t;
tones = zeros(N,size(f,2));
for button=1:12,
    tones(:,button) = sum(sin(f(:,button)*pit))';
end
one   =  tones(:,1)';
two   =  tones(:,2)';
three =  tones(:,3)';
four  =  tones(:,4)';
five  =  tones(:,5)';
six   =  tones(:,6)';
seven =  tones(:,7)';
eight =  tones(:,8)';
nine  =  tones(:,9)';
star  =  tones(:,10)';
zero  =  tones(:,11)';
pound =  tones(:,12)';
pause =  zeros(1,800);
array = [one pause two pause three pause four pause five pause six ...
    pause seven pause eight pause nine pause star pause zero pause...
    pound];

Then I defined the function Phone Decode:

% phoneDecode.m 
% Recieves an array representing variable length DTMF tones alternated with
% variable length pauses and returns a string corresponding to the phone
% number provided.
% Written by Jarick Cammarato on 11/24/12.
function [phoneNum] = phoneDecode(array)
phoneNum = [];
buttonArray =['1' '2' '3'
    '4' '5' '6'
    '7' '8' '9'
    '*' '0' '#'];
digitIndex = find(array); % locates the non-zero indices
start = 1; % Initializing start and stop which will act at the limits of 
stop = 1;  % individual tones.
x = 1;
original_f = [697; 770; 852; 941; 1209; 1336; 1477];
L = round(original_f/8000*205);  % Indices of the DFT
estim_f = round(L*8000/205);
for k = 1:length(digitIndex)-1
    if digitIndex(k) ~= digitIndex(k+1)- 1 && ...
        digitIndex(k-2) ~= digitIndex(k+1)- 4 || ...
            k == length(digitIndex) - 1  
          % if the values of digitIndex are non-sequential it indicates a
          % break has occured due to a pause. If the array end is reached
          % then the final digit must be captured.
          stop = k; % Sets end of array equal to break point.
          tone = array(start:start+204)';
          start = digitIndex(k+1); % updates start to begining of next digit.
          TONE = abs(goertzel(tone,L+1)); % takes DFT of digit using goertzel algorithm
          vert = TONE(1:4)>50;
          horz = TONE(5:7)>50;
          phoneNum = cat(2,phoneNum,buttonArray(vert,horz));
          subplot(4,3,x)
          stem(estim_f,TONE)
          title (phoneNum(:,x))
          ylabel('DFT Magnitude');
          xlabel('Frequency (Hz)')
          x = x + 1;
      end
  end
  set(gca, 'XTick', estim_f, 'XTickLabel', estim_f, 'XLim', [650 1550]);
      ylabel('DFT Magnitude');

Best Answer

Related Solutions

MATLAB: Need help for DTMF Scoring fucntion

MATLAB: DTFM decoding using goertzel algorithm and peak-picking

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