[USRP-users] LFTX output amplitude (Michael Rahaim)

Louis Brown rfengr00 at me.com
Thu Dec 11 09:08:53 EST 2014


Ok what you are describing is the phase accumulator halting to a non zero state when you tune the oscillator back to 0 Hz.  Try generating a very low frequency sine wave (a few Hz) and you see what I mean when you tune it away from 0 Hz and then return it.  When you start you flow with a 0 Hz source, the accumulator is initialized to zero, then it starts accumulating when you tune it to some frequency.  Return it to 0 Hz and it stops at a non-zero phase, which is equivalent to a DC offset.  I'm sure this is the way it is supposed to work, and is what I have observed before.
Lou


> On Dec 11, 2014, at 07:21, Michael Rahaim <mrahaim at bu.edu> wrote:
> 
> Hi Lou,
> 
> I have the output of the LFTX connected to a scope. I'm not using the LFRX in the test loop.
> 
> Best,
> 
> -Mike
> 
>> On Wed, Dec 10, 2014 at 7:44 PM, Louis Brown via USRP-users <usrp-users at lists.ettus.com> wrote:
>> How are you measuring the LFTX output?  With additional test equipment or looping it back into the LFRX?
>> 
>> Lou
>> 
>> 
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> 
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