[hpsdr] PureSignal for HPSDR/Penelope/Mercury

[David]

I remember doing some tests with my Mercury-Penelope setup while Warren
was developing PureSignal, but don't remember details. I think the key
was to have identical processing for the sampled amplifier output (using
Mercury) and the data sent to the DAC on Penny--so that both signals
would be go through identical CIC-FIR filters and decimation.  Mercury
has some capability for multiple receivers, but I'm not sure how that
processing might compare to what's needed for PureSignal.  I would think
that, if Mercury were to digitize the much-attenuated amplifier output
(perhaps using a relay), it might be possible to do the comparison using
the original Tx signal before it is upconverted, rather than a
downconverted-upconverted Tx signal.  There would be significant delay
to be taken into account, but this might be deduced mathematically. 
Unfortunately, I'm not familiar with the details of the PureSignal
algorithm.  While I have some experience with Verilog design and
implementation, I suspect it might be insufficient to make required
changes to FPGA code. 

I, too, would love to be able to use PureSignal with my legacy
hardware... 

David WA8YWQ 

On 2023-05-28 06:41, laurence at nicklebyhouse.co.uk wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> I don't think it is possible. The reason is:
> 
> Puresignal uses an ADC to digitise the amplified output; that bit is
> possible with just one Mercury. It also needs a downconverted *digital*
> sample stream from the upconverted digital TX signal, which would need the
> TX board to fee out a downconverted signal - and as far as I know that isn't
> possible.
> 
> Regards,
> 
> Laurence Barker
> laurence at nicklebyhouse.co.uk
> 
> -----Original Message-----
> From: Hpsdr <hpsdr-bounces at lists.openhpsdr.org> On Behalf Of George Byrkit
> Sent: Sunday, May 28, 2023 12:45 PM
> To: hpsdr at lists.openhpsdr.org
> Subject: Re: [hpsdr] PureSignal for HPSDR/Penelope/Mercury
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> While it might be technically possible, there are lots of hurdles to
> overcome, and PureSignal was not designed/implemented to work on the Mercury
> receiver.
> 
> 1) PureSignal needs an additional phase/clock-synchronous receiver channel
> to get the feedback to correct the signal.  Mercury only has ONE receiver
> channel.  You'd have to hand-stack multiple Mercury boards to begin with...
> 
> 2) PureSignal needs more FPGA memory space for code and everything.  A
> Cyclone III doesn't really have that available for you.
> 
> 3) perhaps bus timing and all are also in the way.
> 
> You should reach out to Dr Warren Pratt, NR0V, who implemented PureSignal.
> 
> 73,
> George Byrkit, K9TRV
> 
> -----Original Message-----
> From: Hpsdr <hpsdr-bounces at lists.openhpsdr.org> On Behalf Of Michael Carey
> Sent: Sunday, May 28, 2023 4:57 AM
> To: hpsdr at lists.openhpsdr.org
> Subject: [hpsdr] PureSignal for HPSDR/Penelope/Mercury
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
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