[hpsdr] ozy/janus as soundcard for digital modes

[Stephen West-Fisher]

Excellent job with small device, that does explain what I am seeing - and
why it is different from when I hook up the Softrock I have. So on to
figuring out why the Janus analogue in/out doesn't appear to do anything....

--
Stephen West-Fisher
N4IK


-----Original Message-----
From: Jeremy McDermond [mailto:mcdermj at xenotropic.com] 
Sent: Thursday, November 03, 2011 9:59 AM
To: Stephen West-Fisher
Subject: Re: [hpsdr] ozy/janus as soundcard for digital modes

We'll see how this goes typing a missive in my iPhone, but I don't have full
Internet connectivity. 

I think part of your confusion is that the I and Q signals have to be
digital. What the Softrock actually does is use analog mixing to create two
analog signals, one representing I (in phase) and one Q (90 degrees out of
phase). Your sound cards right and left channels then are used to capture
each of the I and Q. Janus was designed similarly to sample I and Q from an
SDR 1000. 

You are probably seeing output on your setup because PowerSDR is getting the
audio on the I channel of Janus. You can indeed do a lot with just the real
portion of the signal because it's already been demodulated by your analog
transceiver. You might be able to do similarly on transmit, but it will
probably be very difficult to suppress the Q side of the signal out of PSDR.
You are seeing weird input on the waterfall, etc. because PSDR is expecting
both components of the signal but is only seeing the real demodulated part.
The complex FFTs won't work right without both components. 

--Jeremy (NH6Z)

Sent from my iPhone

On Nov 3, 2011, at 6:27 AM, "Stephen West-Fisher"
<steve at coastaldatasystems.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> No need to shout, and actually I thought I was quite clear in my response
to
> Phil that the TS-480 only has analog audio out and in. My understanding of
> the HPSDR project is that it is for experimentation and learning, so I'm
> doing both.
> 
> So you are saying that I/Q data can go into an analog audio input but an
> analog audio output cannot go into an I/Q data port? Since I was able to
> decode PSK-32 doing just that I'm not sure I completely agree. I do know
the
> panadapter display looks quite odd, and I have not done any comparison of
> how well it works compared to just hooking up to a standard soundcard.
> Performance may be quite marginal, but I did get a positive response.
> 
> So then, since Janus was designed as an A/D and D/A adapter (with the TI
> TLV320AIC23B) and has non I/Q inputs and outputs so it appears to me the
> hardware should be able to handle the appropriate audio to digital
> conversion. If the hardware is capable, then the software would be the
> problem and Phil's response to me leads to that conclusion (windows
driver).
> If there is a problem with this statement, please let me know where I'm
> going wrong.
> 
> At this point the clue I am looking for is where the problem lies, Janus
> firmware or PowerSDR code?
> 
> --
> Stephen West-Fisher
> N4IK
> 
> 
> -----Original Message-----
> From: hpsdr-bounces at lists.openhpsdr.org
> [mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of george byrkit
> Sent: Thursday, November 03, 2011 8:14 AM
> To: hpsdr at lists.openhpsdr.org
> Subject: Re: [hpsdr] ozy/janus as soundcard for digital modes
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Dear Stephen,
> The 'normal sound card' is used to receive I/Q data from the SDR-1000,
which
> is then processed by PowerSDR.
> 
> Janus has better resolution and more stable timing than most sound cards,
> and the USB conntection thru Ozy has much less latency (delay) than a
normal
> sound card would.
> 
> So UNLESS YOUR TS480 OUTPUTS I/Q data (which you have not yet confirmed or
> denied), PowerSDR WILL NOT WORK WITH IT.
> 
> 73,
> George K9TRV
> 
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