[hpsdr] Some things worthy of your attention

[Philip Covington]

On 1/4/07, Krister Wikström <Krister.Wikstrom at stadia.fi> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Some of you are no doubt familiar with the following, but I'd like to
> point your attention to two books that I've found very valuable and in
> my humble opinion should be on every serious SDR developer's bookshelf:
>
> 1. Peter B. Kenington: RF and Baseband Techniques for Software Defined
> Radio, ISBN 1-58053-793-6 (Artech House)
> This tome covers practically all there is to SDR.
>
> 2. Jouko Vankka: Digital Synthesizers and Transmitters for Software
> Radio, ISBN-10 1-4020-3194-7 (Springer)
> Great detail regarding transmitters with high linearity and high
> efficiency, two things that usually don't go hand in hand.
>
>
> Regarding the direction for future developments in HPSDR and other
> projects, I think it might be a good idea to have a look at the new LXI
> standard for interconnecting measuring instruments via the Ethernet.
> Ethernet is ubiquitous, cheap and broadband, and lends itself very well
> for remote control, wired or wireless.
>
> Another relevant standard could be the RP3-01 specification from the
> OBSAI  base station standard. This spec defines a digital interface
> between a remote RF head and the baseband signal processing unit.
>
> I think the present SDR-1000 3-board stack with separate audio and
> control interfaces is not very elegant, to put it mildly. I can
> understand the initial rationale for using a sound card for the A/D and
> D/A conversion, after all most PC:s and all laptops have a sound card.
> BUT, as it turned out, most sound cards aren't good enough, a fact that
> rather negates the initial idea. We definitely need an all-digital
> interface between the RF head and the PC, the sooner the better.
>
> Best regards,
>
> Krister Wikstrom OH2MLQ

I agree.  Look at the progression of "recommended" sound cards for the
SDR-1000.  None of them have been cheap and you can spend a lot of
money over the time you have had the radio in sound card upgrades.

IMHO, the other "problem" with using PC sound cards is that you are
basically leaving a major performance determining factor for the radio
up to the end user.  A poor choice of sound card and misunderstanding
of the issues by the end user potentially can become a (generally
unfounded) bad review of the radio.  It also hides a portion of the
true cost of the radio - the radio is useless without a good sound
card and high enough performance PC.  I can understand why some would
conclude that it is less expensive to stick with their appliance
rice-box radio.

Phil N8VB

 1167927496.0