Hi,
Is there any way of calibrating out or mitigating the
carrier at the WBX tx frequency? I am sending
a wideband signal and the carrier (which I assume is
due to dc coupling in the WBX) is at a significant level
compared to my signal.
- Charles
Kit USRP2 - WBX - UHD
http://www.g4guo.blog
On Tue, May 25, 2010 at 03:17, Charles Brain wrote:
> Is there any way of calibrating out or mitigating the carrier at the WBX tx
> frequency? I am sending
> a wideband signal and the carrier (which I assume is due to dc coupling in
> the WBX) is at a significant level compared to my signal.
Thi
Hi Johnathan,
You can offset the carrier with UHD by passing a 2nd parameter
in the set_tx_freq call. Unfortunately it only seems to work with
small offsets, far too small to take it outside the passband of my
signal. :-( It was not so much of a problem with my DVB-S code
but I am now playing
On Tue, May 25, 2010 at 05:53, Charles Brain wrote:
> You can offset the carrier with UHD by passing a 2nd parameter
> in the set_tx_freq call. Unfortunately it only seems to work with small
> offsets, far too small to take it outside the passband of my
> signal. :-(
I haven't had the opportunit
Hi Johnathan,
I tried an offset of 10 MHz and the output on the spectrum analyser
looks frazzled, it no longer looked clean. Funnily enough the satellite
receiver still managed to lock to the signal.
I am fiddling about with an anti aliasing filter at the moment
but when I have that sorted I wil
Well I have had another look at the offset stuff.
What seems to be happening is that when you apply an offset
you have to scale back the max IQ values being sent to the USRP2.
I get this situation.
No LO offset, great raised cosine shaped QPSK signal
Add LO offset, QPSK signal looks awful.
R
On 05/25/2010 03:17 AM, Charles Brain wrote:
Hi,
Is there any way of calibrating out or mitigating the carrier at the WBX
tx frequency? I am sending
a wideband signal and the carrier (which I assume is due to dc coupling
in the WBX) is at a significant level compared to my signal.
What Johnat
On 05/25/2010 07:40 AM, Charles Brain wrote:
Well I have had another look at the offset stuff.
What seems to be happening is that when you apply an offset you have to
scale back the max IQ values being sent to the USRP2.
I get this situation.
No LO offset, great raised cosine shaped QPSK signa
3 - Measure the amplitude of the TX DC offset as received by the RX (in
this case at -1 MHz). Iteratively adjust your I TX DC offset number
until you get to the lowest power you can see. Then do the same for Q.
If it still isn't low enough, do I again.
Matt
Hi Matt,
Are the settings for
On 06/01/2010 03:41 AM, Charles Brain wrote:
3 - Measure the amplitude of the TX DC offset as received by the RX
(in this case at -1 MHz). Iteratively adjust your I TX DC offset
number until you get to the lowest power you can see. Then do the same
for Q. If it still isn't low enough, do I again.
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