[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Basic Tx works with USRP and usrp_siggen.py
From: |
Matt Ettus |
Subject: |
Re: [Discuss-gnuradio] Basic Tx works with USRP and usrp_siggen.py |
Date: |
Fri, 15 Apr 2005 11:01:26 -0700 |
User-agent: |
Internet Messaging Program (IMP) 4.0-cvs |
Quoting Anastasopoulos Achilleas <address@hidden>:
> I hooked up an analog osciloscope on the Basic Tx daughterboard and tested
> the usrp_siggen.py. It seems to work!
>
> A couple of questions:
>
> 1) what are the units of amplitude? (the default is 16e3)
The signal into the USRP is a 16-bit signed number. 32767 is full scale.
> 2) why does the amplitude change if I change the frequency?
> I guess it is related to a constant multiplicative factor in
> the interploator?
Do you mean change the baseband (software) frequency, the DUC frequency, or the
sample rate?
> 3) What is the expected relationship between the I and Q channel
> outputs? I see the same signal with a phase shif, but not sure
> where the phase shift is comming from.
90 degree phase shift.
Matt