Re: [Discuss-gnuradio] Bandwidth Across USB

[Lee Patton]

Hi John -

16/D bits/sample x 64e10 samples/sec x 1 B/8 bits x 1 MB / 2^20 B <= 32
MB/sec

Therefore,

D >= 16*64e10 /(32*8*2^20) = 3.814 -> 4

So, if you want to transmit twice as many sample across the bus...

D > = 2*16*64e10 /(32*8*2^20) = 7.63 -> 8

...you have to halve your sampling frequency.

Are you aware that there is a -8 option in some of the scripts that
allows you to send 8 bits instead of 16.

Hope that helps,
 - Lee



----- Original Message -----
From: jjw <address@hidden>
Date: Wednesday, April 5, 2006 5:31 pm
Subject: [Discuss-gnuradio] Bandwidth Across USB
To: address@hidden

> 
> I know this is probably an extremely stupid question, but I wanted 
> to get
> some verification.  I've noticed that the minimum decimation rate 
> you can
> use in all of the sample programs is 4 (giving you an effective 
> samplingrate of 16 MHz).  If you are transmitting 1 real channel of 
> data (16 bits)
> at this rate, that seems to be maxing out the USB transfer rate of 
> 32 MB/s. 
> Am I correct in my deduction that you need to use a decimation rate 
> of at
> least 8 in order to transmit complex data (such as for FM 
> demodulation)successfully across the USB?  Thanks. 
> 
> Thanks,
> John
> --
> View this message in context: http://www.nabble.com/Bandwidth-
> Across-USB-t1402318.html#a3773742
> Sent from the GnuRadio forum at Nabble.com.
> 
> 
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>