[hpsdr] New entry in the (almost) SDR arena

[Howard Long]

Folks

> Basically they are paying $159 or $350 for an ADC to use 
> with the SDR-1000 (or even a SoftRock!!!).  If you look at 
> it this way the $95 for a LTC2208 130 MSPS ADC seems pretty 
> cheap.

...plus a digital down converter, then for TX too digital upconverter and
DAC.

I went as far as purchasing parts and evaluation boards for a design just
over two years ago, but after about four months I redesigned using the
QSD/QSE method for two reasons: (1) the programming of the DDCs and DUCs was
very complicated, more than my DSP knowledge at the time was comfortable
with, and perhaps more fundamentally (2) the high power consumption of this
combination was not compatible with the design criteria.

The DUC/DDC I used had the lowest power consumption for any combination I
could find at the time, and this was a TI GC5016. It was only available in a
BGA package, then costing ~$85 per device. For development I purchased a BGA
socket adapter that broke out the pads for mortals to solder - that cost
$400!

At that time the state of the art was 14 bits of ADC at 125MSPS (TI/Burr
Brown ADS5500), so unless you get smart with oversampling, the dynamic range
is likely to be less that QSD/QSE.

73, Howard G6LVB


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