[time-nuts] new WWVB BPSK dev board

[jimlux]

On 12/4/18 8:59 AM, Adrian Godwin wrote:
> I understand why a low-volume shipment of what started as a board costing a
> few pennies costs $50, but does that simply mean that low-cost parts aren't
> the right answer for this sort of application ?
> 
> How would an SDR based on a raspberry pi zero, a suitable ADC and a tuned
> rx circuit compare ?
> 
> 

"suitable ADC" and "tuned Rx circuit" would greatly interact.. the more 
narrow band your Rx, the fewer bits you'd need in your ADC - The Teensy 
($20 arduino clone) can sample at well over 100ksps with a 16 bit (13-14 
ENOB) differential input, and I'll bet you could make a simple PSK 
demodulator in software, either on the Teensy or on the host PC  (which 
could be a RPi or Beagle) connected via USB.


https://www.pjrc.com/store/teensy32.html

They also sell a higher performance audio interface that might be useful:
https://www.pjrc.com/store/teensy3_audio.html
Although it's 44.1 kHz sample rate - but might actually support other rates.


So the real question is where can you find an inexpensive 60kHz front 
end amplifier.

The computer (whether arduino, teensy, beagle, or Rpi) isn't the 
limiting thing, it's the RF to digital interface. -

Find a $20 60kHz narrow band receiver/ADC , and the rest is straightforward.