If you are running the code in demo mode, and it is taking in stuff from
a typical sound card, that hump to the left of center is the 1/f noise
- DC junk in the sound card. You can see a hint of this in some Flex
3000 and 5000 radios depending on the quality of your grounding, etc.
but on noisy bands, not much.
This is the reason the power spectrum is not centered. We offset from
DC (0 Hz in a -Fs/2 , Fs/2 IF band where Fs is the sample rate) to
avoid the degradation from the noise at the center of the passband on
receive. On transmit, it makes almost no difference since it is so far
down.
Bob
N4HY
Jack Haverty wrote:
My Flex-3000 hasn't arrived yet, but I see this same "phantom image"
behavior running PowerSDR 18.0 in demo mode. It also occurred in prior
version 16. I figured I'd wait for the actual radio since it might be
an artifact of whatever demo mode does to create the band-noise. It
looks like just a fairly steady carrier at the position you describe,
and when you center on it, it's not there, but pops back up a fraction
of a second later at the offset position.
/Jack Haverty
Point Arena, CA
On Wed, 2009-04-29 at 20:44 -0400, Tim Ellison wrote:
When ever anyone has an issue, it is imperative that you tell what version of PowerSDR you are using because without that info, there is no reference point to start from.
-Tim
-----Original Message-----
From: flexradio-boun...@flex-radio.biz
[mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Randy Emerzian
Sent: Wednesday, April 29, 2009 8:31 PM
To: flexradio@flex-radio.biz
Subject: [Flexradio] Flex 5000 Phantom Image on panadaptor dispaly
Hello,
I seem to have a phantom image of a modulated signal just to the left of center. When I click on it to listen the dispay re-centers, and I hear no audio in any mode. The Image re-apeard at the same location ( two lined left of center) no matter what freq I am centered on. Any Ideas?
Randy - KI6VAU
_______________________________________________
FlexRadio Systems Mailing List
FlexRadio@flex-radio.biz
http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/
Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
--
(Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio
Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
NJQRP, QRP ARCI, QCWA, FRC.
"You don't need to see the whole staircase, just
take the first step.", MLK.
Twitter:rwmcgwier
Active: Facebook,Myspace,LinkedIn
_______________________________________________
FlexRadio Systems Mailing List
FlexRadio@flex-radio.biz
http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/
Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
