Change bitrate dynamically in tunnel.py

GNU Radio
1

Hi all,

Now I use tunnel.py with USRP2.

I set bitrate when I run tunnel.py.
I cannot change the bitrate until I finish tunnel.py.
But, I want to change bitrate dynamically when I am running tunnel.py.

Does anyone know the ways to change bitrate dynamically?

regards,
kouta

2

On Mon, Jan 9, 2012 at 2:24 AM, Kouta NISHIDA <
[email protected]> wrote:

regards,
kouta

Hi Kouta,
It’s not set up to work that way right now, but you should be able to
hack
it to do what you want.

There are a couple of settings that affect the bitrate: the rate of the
USRP and the number of samples per symbol (sps). In the current
implementations of the PSK modulations, you can set a real number for
the
sps, so you should be able to change that to affect the bit rate. But
remember, look for any place that is used since you’ll have to also
reset
the taps for the filters on both the RX and TX sides.

You can also set the sample rate of the USRP as well to affect this.

Let us know how you do with this.

Tom

3

Tom R. wrote:

But, I want to change bitrate dynamically when I am running tunnel.py.

hack it to do what you want.
Let us know how you do with this.

Tom

Thank you for your advice.

I will try setting the sample rate of the USRP to change bitrate
dynamically.

I found the parameter that Actual Bitrate with pick_bitrate.py
Is the sample rate of the USRP Actual Bitrate ?

Would you tell me it if there are the file and parameter that I should
pay attention to ?

regards,
kouta

4

On Tue, Jan 10, 2012 at 3:37 AM, Kouta NISHIDA <
[email protected]> wrote:

dynamically.

I found the parameter that Actual Bitrate with pick_bitrate.py
Is the sample rate of the USRP Actual Bitrate ?

Would you tell me it if there are the file and parameter that I should pay
attention to ?

regards,
kouta

Kouta,
If you’re still using the pick_bitrate.py file, it sounds like you are
on
an older release (pre 3.5). In that case, you might have more trouble
changing the bitrate (at least arbitrarily). But if you are using that
version, you use that script to set the interpolation or decimation
rates
of the USRP as well as the number of samples per symbol based on a
desired
rate. So using it, if you want to set a new bit rate, you will receive
new
values for both of these parameters.

Tom