Re: [Discuss-gnuradio] Problems using wavfile_source

[Jonathan Coveney]

I was able to get a 32KHz file...now it lets me go up to 640KHz sample rate, but it won't let me go beyond that. At anything beyond that it gives me the insufficient extremals error. I wouldn't need so many samples, except I want .2KHz between signals for ideal resolution. Any insight into what causes the insufficient extremals? It seems odd that I wouldn't be able to set it past 640KHz, given that when I sample from the usrp I can get up to 4MS/s...very odd

2009/8/14 Eric Blossom <address@hidden>

On Fri, Aug 14, 2009 at 04:10:11PM -0400, Jonathan Coveney wrote:
> I'm modifying fm_tx4 so that I can use wav files instead of dat files as a
> source, and output a file instead of sound.
>
> I'm having issues with sample rate. I've attached the code, but here is the
> modified pipeline code, which is used to create the FM modulated signal from
> the wavfile
>
> This code works if I set mult to <= 9 (meaning in fmtx = blks2.nbfm_tx
> (audio_rate, if_rate, max_dev=5e3, tau=75e-6) that the if_rate has to be an
> integer multiple of 44.1KHz less than 9*44.1KHz). This is really vexing! If
> the multiple is 10 or higher, I get the error below.
>
> I need the sample rate to be higher that way I can have lots of disparate
> signals. It's confusing because if audio_rate is 32KHz, then if_rate can be
> set arbitrarily large. I can't do that, though, because the sample rate of a
> wav file is 44.1KHz.

FWIW, I'm pretty sure a .wav file can contain samples at pretty much any sample rate...
There's a field in the header that gives the sample rate.

Eric