[hpsdr] The Basics (with updates)

Wed May 3 12:17:38 PDT 2006

Bob,
Why wouldn't we want to use a SDX HELAPS based design?

(a) It helps the AMSAT effort by increasing the use of the design (more testing and more design review eyeballs)
(b) It helps the SDR community out by using a common design to get to production quicker

I've argued since my Lockheed Martin days that we ought to mass produce OSCARs so we don't have a single point of failure (nor have all eggs in one basket). Having commonalities with the HPSDR will only help to validate the design, performance, and reliability. SpaceQual hardware always cost more because they only want quantity ONE, mass production will bring the cost down.

Alex, N3NP

----- Original Message ----
From: Robert McGwier <rwmcgwier at comcast.net>
To: Philip Covington <p.covington at gmail.com>
Cc: hpsdr at hpsdr.org
Sent: Wednesday, May 3, 2006 11:41:37 AM
Subject: Re: [hpsdr] The Basics (with updates)

***** High Performance Software Defined Radio Discussion List *****

Philip Covington wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi Alex,
>
> On 5/3/06, Alex <harvilchuck at yahoo.com> wrote:
>   
>> ***** High Performance Software Defined Radio Discussion List *****
>>     
> <snip>
>   
>> More questions:
>>
>> How is OZYMANDIAS "bigger" than LIONHEART?
>>     
>
> It uses a Cyclone II part with more I/O.
>
>   
>> What is the development status of LIONHEART?
>>     
>
> Since we haven't had a status update from Leon in quite a while I
> would say that the LIONHEART is stalled.  I would guess that Leon has
> lost interest in the project since he has also not ordered an ATLAS
> board and did not participate in the review of the ATLAS design.
>
> Leon?
>
>   
>> Is JANUS interfacing to SDR-1000 just for I/Q signals or is it also providing the LPT-based control interface?
>>     
>
> We *need* a FPGA_USB board to continue on with long term this project
> so that is why OZY was created.
>
>   
>> Are OZYMANDIAS, MERCURY and SASQUATCH going to use the Altera Cyclone II FPGA?
>>     
>
> OZY will use a 208 pin QFP Cyclone II (EP2C5)
>
> The MERCURY will probably use the same.
>
> Don't know about SASQUATCH.
>
> A couple of other things to throw out there:
>
> 1. GPIO board - I would like to see a general purpose I/O board that
> has buffered/protected industrial strength input and outputs.  Maybe
> an optical encoder interface on it also.  I would envision that this
> GP I/O board would communicate across the backplane using an
> SPI/Microwire interface since I2C is probably too slow for this.
>   
That sounds good.
> 2. TX System - My goal is to put together a complete SDR RX/TX.  Right
> now we are building the RX components.  We need to start thinking
> about TX.  For sure I'd like the TX to be independent (can operate at
> the same time) from the RX system.  It is not clear if it should be a
> DDS-QSE type of system or a class E amp/PWM modulator type of system. 
> I am leaning towards the latter if possible.  Or maybe a DAC/DUC based
> system?  Lots to think about...
>   

I would definitely do at least Class C, and if we can find devices which 
will not have too low a resistive component of their impedance,  Class E 
amplifier chain.  If we use PWM for the envelope,  we can get 
<<<HUGE>>>  efficiencies .  Also,  since this is DSP,  if we provide the 
correct sensing,  we can make this "envelope elimination and 
restoration"  amplifier chain automatically adaptable to changing 
loads.  Listen,  we are talking 100w  output transmitters with 120 watts 
of DC power going into them and having linearity as measured in the ARRL 
labs better than any TX ever measured there.  I am viewing HPSDR as the 
"skunk works" for the future of radio and I would love to see us push 
this envelope (pun is absolutely intended) to the limit.  We will need a 
very good switcher power supply to do the envelope restoration and 
ideally,  a softrock or lesser receiver to do a "perfect" job of sensing 
the amplifier needs dynamically.  That would be the ideal.  Since Lyle, 
Frank, and I are already having to do this for a wider band application 
than a typical transceiver (the AMSAT SDX HELAPS exciter),  that work 
should be adaptable to this job.  I would hope that we can all build on/ 
steal from each other here for efficiencies/nonduplication sake.  Lyle 
wants to use an Actel part for the EER transmitter in the SDX but to me 
personally,  it is just verilog that might need a few changes.

> 3.  PROTO board - The PROTO board has already been mentioned.  This
> would be great for experimentation.
>
> 4. DDS board - It would be nice to have one for at least general
> purpose signal generation for VNA type applications.  I would envision
> at least two sets of independent quadrature outputs.
>   
AD9958, AD9959
http://www.analog.com/en/prod/0,,770_843_AD9959,00.html

DO NOT be put off or fooled by the 10 bit DAC.  Analog devices has 
learned a whole lot about doing this kind of work.  This device produces 
extremely clean signals.

There are several sources for the oscillators.  One that we know and 
love will require a group buy to get the several week lead time 500 MHz 
oscillator.   With the reference locking done to 1 pps, or 10 MHz, etc. 
external references,  this my be tamed to 10^-12.  I have done it with 
CNS for their clock II  (  http://www.cnssys.com ) because I needed it 
for a work project.

All of this is beginning to get VERY interesting and I do like the 
multiple projects needing the same generic things.
> 73 de Phil N8VB
>   
73
Bob
N4HY

-- 
AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,
NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman
Laziness is the number one inspiration for ingenuity.  Guilty as charged!

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