Re: how is interpolation rate dynamically set?

Thank you, Brian!

Now i know how the interpolation changes, but if bitrate were set, how
are interp/decim rate and
samples-per-symbol derived respectively? Is there a default value for
interpolation rate? Thanks!!!

Bill

----- Original Message ----
From: Brian P. [email protected]
To: Bill S. [email protected]
Cc: [email protected]
Sent: Friday, September 26, 2008 4:09:25 PM
Subject: Re: [Discuss-gnuradio] how is interpolation rate dynamically
set?

On Fri, Sep 26, 2008 at 4:00 PM, Bill S.
[email protected] wrote:

Hello, everybody!

I am working on the demo file:
gnuradio-examples/python/digital/benchmark_tx.py. In the file
transmit_path.py, it is said “specify bitrate. samples-per-symbol and
interp/decim will be derived.” How are interp/decim rate and
samples-per-symbol derived respectively? what is the range for the variable
interpolation rate? Is interpolation rate increased as a multiple of 4?
could anyone tell me where i can find the dynamical range of interpolation
rate?

Try the wiki:

http://gnuradio.org/trac/wiki/UsrpFPGA#TransmitChain

The interpolating CIC filter, I believe, can handle integers in the
range [4,255]. The source can be found here:

http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib

Brian

On Fri, Sep 26, 2008 at 6:10 PM, Bill S.
[email protected] wrote:

Thank you, Brian!

Now i know how the interpolation changes, but if bitrate were set, how are
interp/decim rate and
samples-per-symbol derived respectively? Is there a default value for
interpolation rate? Thanks!!!

I believe the USRP operates at 128Msps for the TX DAC. This value
does not change.

Brian

On Fri, Sep 26, 2008 at 03:10:14PM -0700, Bill S. wrote:

Thank you, Brian!

Now i know how the interpolation changes, but if bitrate were set, how are interp/decim rate and
samples-per-symbol derived respectively? Is there a default value for interpolation rate? Thanks!!!

Bill

One of the joys of Free Software is that it comes with the source code.

Take a look at gnuradio-examples/python/digital/pick_bitrate.py

Eric