downsampling a wave file

[moonnightingale]

I am having a wave file
i want to downsample the signal with lets suppose M= 5. So first i have to use Low pass filter of 6 KHz
I know this can be done with upsample and downsample command of matlab but is there any a way i can do downsampling without built in command of matlab
thanks

 

[klystron]

Use an over-sample algorithm. for example 4 x over sample ; take the average of 4 samples. The effective sampling rate is reduced by a factor 4. The Nyquist criteria is maintained

 

[moonnightingale]

what abt low pass filter
how to implement that

 

[klystron]

You can implement that with a FIR or IIR digital filter in Matab. The IIR is better

 

[Salmantariq]

Please help me with one of this assignment.please help me out please i request you


Write a generic function to implement resampling with following prototype
y = myresample(x,L,M);
% L is an integer representing upsampling rate
% M is an integer representing downsampling rate
% x is the 1-D vector representing input signal of any length
% y is the 1-D vector representing output signal.
Note: save file with name myresample.m
Write a generic function to implement a Second Order IIR filter with following prototype
y = myfilter(b,a,x);
% b is a 1×3 vector representing numerator coefficients
% a is a 1×3 vector representing denominator coefficients
% x is the 1-D vector representing input signal of any length
% y is the 1-D vector representing output signal of same length as of x.
Note: save file with name myfilter.m
Read chimes.wav and define an LTI system
b =[0.1875 0 -0.1875]
a =[1.0000 -1.3085 0.6251]
use your myfilter function to generate output and compare it with output from built in function

---------- Post added at 00:50 ---------- Previous post was at 00:48 ----------

Please help me solving this problem please

Write a generic function to implement resampling with following prototype
y = myresample(x,L,M);
% L is an integer representing upsampling rate
% M is an integer representing downsampling rate
% x is the 1-D vector representing input signal of any length
% y is the 1-D vector representing output signal.
Note: save file with name myresample.m
Write a generic function to implement a Second Order IIR filter with following prototype
y = myfilter(b,a,x);
% b is a 1×3 vector representing numerator coefficients
% a is a 1×3 vector representing denominator coefficients
% x is the 1-D vector representing input signal of any length
% y is the 1-D vector representing output signal of same length as of x.
Note: save file with name myfilter.m
Read chimes.wav and define an LTI system
b =[0.1875 0 -0.1875]
a =[1.0000 -1.3085 0.6251]
use your myfilter function to generate output and compare it with output from built in function