FIR filters

[peer123]

Hi there,

I am I have a .wav file and have done the FFT spectrum using audacity software.

Now, I require to use a bandpass FIR filter to filter out the unwanted frequencies.

Is this possible to insert the .wav file in Multisim or an audacity generated file?

Can you pls reply me as soon as you can

Thanks..

[Tien_P · Accepted solution]

Hi Peer123,

Multisim cannot import .wav file, but if you have LabVIEW you can create a VI that reads a .wav file and then generate a .tdms or .lvm file, Multisim can read these files format.  Attached is a LabVIEW VI that reads a .wav file and generate a .tdms.  In Multisim, place the TDM_Voltage source on the work area, double click on it and select the "Browse" button, to select the .tdms file generated by LabVIEW.  

[_user32]

peer123,

I created a simple Multisim VI that all allows you to load in a 8 or 16 bit .wav file (U8 or I16, mono or stereo formats) and play the file back through Multisim.   Place the .llb in the appropriate folder location as indicated below so that it can be loaded into Multisim when it starts up.

This was created in LabVIEW 2010 and therefore works in Multisim v11.0.1 or later.

Place the LabVIEW VI (.llb) file here:

C:\Documents and Settings\All Users\Documents\National Instruments\Circuit Design Suite 11.0\LVInstruments

or you can try here depending on your OS...

C:\Users\Public\Documents\National Instruments\Circuit Design Suite 11.0\LVInstruments

They will load in the same LabVIEW Instruments menu, under "User Defined LV Instruments".

I also included a small test circuit for you to use.   Note I also placed the Speaker instrument which will allow you to playback the audio sound after simulation is stopped.

I tested several files (U8 and I8 mono and stereo format only) from here with no issues.

Regards,

Pat N

[peer123]

hey thanx for the reply.

But I have 32 bit wave file. Will it work?or I need to convert it into 16 bit nd if I convert it my frequency will get change.

I will try to work on it though.

[_user32]

peer123,

I used the standard wav files from here: 

http://www-mmsp.ece.mcgill.ca/documents/audioformats/wave/Samples.html

Unfortunately I could not get the 32 bit files or any extended wav file format to work.   The underlying LabVIEW VI appears to only support the standard U8 and I16 formats, not the extended wav file formats.

It appears there are many wav converter programs out there.  If you find a good converter, it shouldn't impact your frequency.

Please let us know which converter software works well for this in case someone else would like to do the same with extended format (24, 32-bit) wav files.

Regards,

Pat N

[peer123]

Hi there,

I used audacity software to view the fft spectrum of the .wav file. It supports different sampling rate and bits.

It is about the breakage of sound detection and I need to figure out the frequency band for it and later need to do bandpass filtering to get the exact band of frequency. Now I am in the stage to build the filter and still not sure what filter to use. I found difficult to build Digital filter.

[peer123]

Hello Tien, Thanks for your reply but unfortunately I was not able to open the files as I am having the 8.5 version of Lab-view. Also here by I am attaching my file. Can you please let me know the steps for generating the .tdms or .lvm files for the wave file.

[Tien_P]

Hi Peer123,

I saved the file for LabVIEW 8.5, hopefully, you can open it.  If you can't open the VI, look at the .png file to view the block diagram.