Re: [Discuss-gnuradio] Power，Band width and spectrum switch problems

[Johnson_lu]

Thanks for Eric's reply. I tried the frequency switch without lock/unlock,
the switches works well, no failures happen again.

Eric Blossom wrote:
> 
> On Tue, Jun 29, 2010 at 11:23:36PM -0700, Johnson_lu 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() 
> 
> FWIW, there's no need to use lock/unlock to change the frequency.
> You only need to use those when you are reconfiguring the topology of
> the graph.
> 
> Try it without those and see if it works.
> 
> Eric
> 
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> 

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