# DTMF using MATLAB

Started by May 24, 2006
```Can any body help me in writing code of following problem in MATLAB
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::=

Design digital oscillators for DTMF frequencies at sample rate of 22500

sp/sec
Generate a seven digit DTMF using Digital Oscillators and write it in a

wav file

```
```haroon.khalil@gmail.com wrote:

> Can any body help me in writing code of following problem in MATLAB
> :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::&#2013266093;::::::::::::::::::::::
>
> Design digital oscillators for DTMF frequencies at sample rate of 22500
>
> sp/sec
> Generate a seven digit DTMF using Digital Oscillators and write it in a
>
> wav file
>

Which part are you having difficulty with ?

Paul
```
```Fs = 22.5 kHz

There are two DTMF frequencies

F1 = [L0 L1 L2 L3] % four low frequencies
F2 = [H0 H1 H2 H3] % four frequencies

ocillator coefficients for example for L0
numerator = 1
denominator = [0.5 -cos(2*pi*L0/Fs) 0.5]

When you want to generate you input an impulse, also you need to adjust
in order to get the desired amplitude value. An expert here might point
out a better way

help wavwrite

cheers

```