Designing a Digital filter from given Transfer function ? Coefficient Calculation ?

First of all i am not a expert in signal processing i just know the A B C

my question is how to design a filter for my speech codec where i capture speech and compress and tx it over air

so in this event my codec hardware from Texas Instruments TLV320AIC3204 gives me a flexibility to program the filters present in it by the given transfer function

        N0   + (N1 * z^-1)
  H(z)=---------------------
        2^23 - (D1 * z^-1)

Above is an IIR Filter Example

my job is to find out the filter coefficients NO,N1,D1 and fill them up to the codec chip so that i can realize it on an hardware for that i want to take the help of matlab

any way i have some other transfer functions also waiting like biquad filters with a transfer function as below using which i can cascade a LPF and HPF to form a BPF using Biquad blocks

Transfer Function of Each biquad:

         N0  + (2* N1 * z^-1 ) +  (N2 * z^-2)
H(z)=----------------------------------------
      (2^23) -   (D1 * z^-1)   -  (D2 * z^-2)

how to realise this filter in matlab now Help me please

Answer 1

[shyam]

Any One There PLZ Reply me

Answer 2

[Dimka]

That is, You need to calculate filter coefficients? And we are given?

[shyam]

yes i just need to calculate the filter coefficients by given sampling frequency 8000Hz BPF:(200-3500Hz)

Answer 3

[Dimka]

Maybe it would be you can help...

 clc; clear; close all;
 fs = 8e3;
 fc = [200 3.5e3];
 order = 2;
 % b - nominator of complex transfer function; a - denominator;
 [b, a] = butter(order, 2*fc/fs, 'bandpass');
 disp([{'Numerator'} num2str(b); {'Denominator'} num2str(a)])
 %%check
 f = fs/2*linspace(0, 1, 8192);
 h = freqz(b,a, 8192);
 K_dB = 20*log10(abs(h));
 plot(f/1e3, K_dB, fc/1e3, [-3 -3], 'or', 'LineWidth', 2); grid on;
 xlabel('frequency, kHz'); ylabel('|H|, dB')
 axis([min(f/1e3) max(f/1e3) -60 10])

[shyam]

:) may be you have not read my question completely the filter coefficients obtained by above sample code may not help

i have explained you my problem it is using the above transfer function i have mentioned in my question

i have to design the filter then from the obtained coefficients i can program my codec if you want i could elaborate more

[Dimka]

That is, You need calculate the coefficients just for your transfer function?

[karrar mosawe]

thank for this example now i can do this easy