[hpsdr] Duplex and Full Duplex

[David McQuate]

Two issues--
(1)  The current USB communication protocol contains only one frequency, 
which is used by both
Penelope and Mercury, so RX & TX are on the same frequency.  For useful 
full duplex, we'll need
to send separate RX and TX frequencies.

(2) PowerSDR uses DttSP, which is set up to switch between RX and TX 
modes, processing
received audio in RX, and mic audio (or other modulation) during TX.  
This is not a fundamental
limitation, as the code can be easily modified to perform both kinds of 
processing "simultaneously".
Full duplex will require higher CPU usage. 

The Alex filter modules are somewhat independent, but there is a T/R 
relay.  Some thought will be
required here.

Dave
wa8ywq

John Melton wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> And I am also running full duplex in the TX code I am working on in 
> ghpsdr so I can monitor the signal using Mercury.
>
> I am thinking of making this an option in the code so I can run 
> satellite using a 2 Mtr transverter and a 70 cm Transverter.
>
> -- John g0orx/n6lyt
>
>
> On 07/23/09 14:41, Henry Vredegoor wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Well I see Phil already answered that question.
>>
>> He should know....... ;-)
>>
>> 73's,
>>
>> Henry.
>>
>>> -----Original Message-----
>>> From: hpsdr-bounces at lists.openhpsdr.org 
>>> [mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of Henry Vredegoor
>>> Sent: donderdag 23 juli 2009 15:38
>>> To: 'Richard Ames'; hpsdr at openhpsdr.org
>>> Subject: Re: [hpsdr] Duplex and Full Duplex
>>>
>>>
>>> ***** High Performance Software Defined Radio Discussion List *****
>>>
>>>
>>>
>>> I'm almost sure at this moment it can not work in this way.
>>> I think the whole system simply wasn't designed and implemented with 
>>> duplex
>>> in mind (?)
>>>
>>> I think you would have to check each functional block in the chain from
>>> antenna to the loudspeaker and from the microphone to the antenna 
>>> for this
>>> operating mode.
>>> If it could be MADE to work (It is SOFTWARE defined radio after 
>>> all.... ;-)
>>> ), is whole other question.
>>> I think it would be difficult but probably doable
>>>
>>> Quick, first thoughts:
>>>
>>> PC (audio route): Yes it can
>>>
>>> Software (PowerSDR):
>>> I think not, I think it would require some serious changes to make it
>>> "aware" of a duplex situation.
>>> Other software don't know.
>>>
>>> USB interface to/from Ozy: Yes it can
>>>
>>> Ozy itself: Same problem as Power SDR, it probably is not aware of a 
>>> duplex
>>> situation as well.
>>>
>>> Atlas Bus interface: Could be, would require different paths for RX 
>>> and TX
>>> data from Mercury and to Penny
>>>
>>> Mercury: Yes it could if it has it's own (Alex) RX path to the antenna
>>>
>>> Penelope: Yes it could if it has it's own (Alex) TX path to the antenna
>>> Alex: Since it shares it's filters for RX and TX you would need two
>>>
>>> In general: The whole system has to be (logically) aware of this 
>>> operating
>>> mode and I think it currently is not.
>>> Things like interlocking between RX and TX, a second (the duplex) 
>>> frequency
>>> (This is not VFO A and VFO B)
>>>
>>> Another issue would probably be performance of the various software 
>>> parts,
>>> including Ozy hardware (FPGA firmware)
>>>
>>> After having written down all this I would think the answer is not 
>>> at the
>>> moment, but maybe doable.
>>>
>>> But others can answer this much better than I can.
>>>
>>> 73's,
>>>
>>> Henry.
>>>
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: hpsdr-bounces at lists.openhpsdr.org 
>>>> [mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of Richard Ames
>>>> Sent: donderdag 23 juli 2009 14:02
>>>> To: hpsdr at openhpsdr.org
>>>> Subject: [hpsdr] Duplex and Full Duplex
>>>>
>>>>
>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>
>>>> I was asked last night weather the HPSDR could do duplex....
>>>>
>>>> I didn't know how to answer.  I sure with separate receiver and 
>>>> exciter
>>>> and software clients you could rig it up to do this on separate
>>>> frequencies.
>>>>
>>>> Can you do it with the receiver and exciter plugged it to 
>>> one alex bus
>>>> to receive and transmit at the same time???  Separate 
>>> frequencies and
>>>> antennas.
>>>>
>>>> Thanks, Richard.
>>>>



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