Topband: Analog to Digital converter for 1.8MHz

[Steve Ireland]

G'day

It seems that the days of converting 1.8MHz signals from analog to digital
at our antennas seem just about here.  On October 14 last year Texas
Instruments released its ADS7881 A to D converter - good to 1.8MHz and
retailing at about US$7 each.


>Analog-to-Digital Converter achieves 4 msps.

>Model ADS7881 combines 12-bit resolution, 1 LSB linearity, -91 dB harmonic
distortion, 71.5 dB signal-to-noise, and 95 mW power dissipation. It
addresses high-speed data acquisition needs by providing specification with
input signal frequency as high as 1.8 MHz. Suited for optical networking,
imaging, and telecommunications, SAR-based unit integrates internal
reference and reference buffer, and has pseudo-differential, unipolar input
range of 0–2.5 V.

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I'd be interested to hear from anyone on the reflector who has started to
think about a topband receiver along these lines - a very sharp front end
filtering system (the old Cohn filters are pretty good), an A to D
converter followed by a dsp board to do all the filtering.

Vy 73

Steve, VK6VZ