[Discuss-gnuradio] offset at input of LF_RX

[ematlis]

Hi all-

can anybody explain why the USRP/ LF_RX would seem to introduce a DC bias 
or offset to a signal generated by a function generator?  I have a 
function generator configured to produce a 1 kHz .1 V P-P signal into a 50 
Ohm load.  I have a Lecroy digital oscilloscope configured with the input 
at high-impedance to monitor the signal.  When I connect the signal to the 
USRP, I see the trace on the Lecroy gets shifted UP by about .06 volts, ie 
I have to add a -0.06 V offset at the function generator to zero the bias.

Oddly enough, usrp_oscope.py doesn't show any DC bias whatsoever, 
regardless of what offset I put into the function generator.  Maybe it's 
removed inside the flow-graph?

Any thoughts on either of these questions?

thanks.

eric

************************************
Eric H. Matlis, Ph.D.
Aerospace & Mechanical Engineering Dept.
120 Hessert Center for Aerospace Research
University of Notre Dame
Notre Dame, IN 46556-5684
Phone: (574) 631-6054
Fax:   (574) 631-8355