Re: [Discuss-gnuradio] Power，Bandwidth and spectru m switch problems

[An He]

1. Change tx-gain if you are using tunnel.py. The default value is set to the mid value. Use -h to find out more.

2. Spectrum analyzer would help you to observe. I believe you can also "calculate" based on your settings. Maybe someone can point out where in the code the bandwidth relationship is determined.

 

3. Not sure why. I thought someone had implemented a FH system.

 

An

On Wed, Jun 30, 2010 at 2:23 AM, Johnson_lu <address@hidden> wrote:

Hi guys，
Could anybody can help me for these problems？
1、I varied Tx_amplitude from 0.1 to 1 and measured the output with a
spectrum analyzer. But the changes are very little. The output is almost the
same when Tx_amplitude is 0.1 and 1.  How can I reduce the transmit power to
a very little value?

2、How do I know bandwidth of transmission and reception channels in
tunnel.py?

3、I am using an USRP2 with Gnu Radio and XCVR2450 as daughterboard. I want
to switch frequency among different channels 2.4G~2.5G. However, I find that
switch only can succeed about 20 times, then fails.
The python code is:
       self.tb.lock()
       ok = self.tb.txpath.set_freq(new_freq)
       if not ok:
           print "Failed to set Tx frequency"
           raise SystemExit
       ok = self.tb.rxpath.set_freq(new_freq)
       if not ok:
           print "Failed to set Rx frequency"
           raise SystemExit
       self.tb.unlock()


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