aneeshkm106 said:I'm want to implement Band Stop Digital filter for audio wave using VC++.
For this Which FFT is good?
How can i manipulate audio samples?
What is the nature of samples?
When i tried ;the samples are of int type.For calculations using radix-2 fft these int values are converted to decimal-point values.Here is my doubt...While casting decimal-point to int some data lost.
Please help me ....
aneeshkm106 said:I did audio file reading as per wav format. I think samples are in little endian formate.
For manipulating samples how can i take each sample...?or Can we take it as bulk sample..? Here is my doubt...
Is it the correct method of taking each sample separately?
When taking wav samples what its nature?
I'm not sure about the noise level for hearing the wav sound clearly as possile.
Please help me..........
aneeshkm106 said:I want to write code for cutting certain freq. from wav file only.
Reading wav file means as like binary file reading in c/c++ . not trying to play wav file.
I tried it using FFT .But reading and writting binary file(Wav file) as per Canonical Format. There is only this format
I tried this , but when i read Canonical Format from documents samples are in HEX values.
.First i convert HEX to DECI and manipulate using FFT radix-2 and then reconvert to HEX .
Then write it to file as Canonical Format.I suppose writing is correct .there is some doubt...
Becoz. avoiding FFT ,simply read + conversion +reconversion+ write..... resulting same file and sound.
Now i understood it is binary file . need not conversion.Simply take the samples as int
After adding FFT the file is noisy...
When read the samples one by one using array ,there is any problem with speed or anything fail?
I did this in windows programming(VC++).
Bulk reading means ,in windows programming any method for reading all sample at a time?
Please help me?
I'm a beginner...............
aneeshkm106 said:We tried Input -> FFT -> frequency cut -> IFFT -> output using C language.
We thought FFT will be suitable becoz it is fast.We were not familiar with DSP.
From your suggestion FIR would suit.
Now we are going to implement Band stop filter using FIR using windows programming.
//"Input -> filter -> output
is better and (depending on the filter), faster.""//
we didn't understand the above sentence .
What did you mean by Filter?
Can we implement This Filter in software?This is actually we want to implement
we think we can cut freq. in freq. domain.
For this the input signal(time domain) --> Freq. daimain<cut the freq>-->output(time domain).
aneeshkm106 said:I don\'t know what kind of stop band you want and I don\'t know what atteuation
you want. Here is an example design of a filter which cuts between frequencies
0.2 and 0.3. The stop band attenuation is 80 dB and its length is 68 taps.
If you want a greater attenuation it will cost you more taps.
It is therefore very flat in the passband (I have set +/- 0.1 dB).
Careful with the +/- setting, your signal output may roll over!!
Sir
Are u using any special tool like MATLAB?But we cant use such tools.Our program strictly must be in ANSI C.
We are writing this code to develop as one of the plug-ins for an IVR(Interactive Voice Response) system.
We are not sure about the what kind of band stop filter and what attenuation we need.
Will Parks - Maclellan program suit for our problem?
Please give me valuable suggestions..... Keeping in mind ur great response......
aneeshkm106 said:Sir
The Company gave only less information
//" Implement a band stop filter as a plug-in using ANSI C" //
For example from a wav file cut the freq between 300Hz and 500Hz for avoiding noise.This is the only information we have.
Our duty is to develop maximum efficient filter with highly optimized code.
aneeshkm106 said:I want to develop my project as plug-in.
I tried it .But I can't touch it. I understood it is a special type DLL.I refer so many but i can't reach final
I want basic about it
Please Help me....
aneeshkm106 said:Sir
I'm going to implement band stop FIR filter using Remez
I have c code for band pass filter using Remez
Can i convert it to Band stop?
Please help me
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