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I'd like to interface with a legacy system that uses BPSK at ~5MHz to transmit data. I understand the basic idea of BPSK - that it's a 180 degree phase shift to represent data - but I'm having a hard time finding examples that take an Arduino or something and create a BPSK radio.

Most of the documentation I find online shows a basic block diagram like this: BPSK Mixer from app note

I understand we're mixing sine phases based on bits from a processor, how would I implement this with OpAmps?

Voltage Spike
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Drewster
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    Check out some of this guys videos https://www.youtube.com/channel/UC0UDLi6A-auU9YetO-ShZug/videos. Plenty of ideas and very well presented. – Buck8pe Mar 11 '21 at 07:44
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    You're USA - take a look at station WWVB (transmitting 60 kHz carrier, BPSK + AM). An Arduino cannot *quite* sample an amplified signal - its analog-to-digital converter is a bit too slow. But its processing power is capable of demodulation, and decoding bits. A Microchip PIC16F1455 has a faster ADC, but still requires under-sampling the carrier - it can do the whole thing in efficiently coded assembler. Many ARM M0 types would be a better fit for this job. – glen_geek Mar 11 '21 at 13:50
  • Thanks, guys- please take my humble upvotes – Drewster Mar 11 '21 at 15:12

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Get a copy of the "ARRL Handbook 2021" from your local library, it is a Six-Volume Book Set. It should show what you are trying to decode but you will have to interpret it as I do not believe it shows a connection to an arduino. This link has a lot more information: https://www2.eecs.berkeley.edu/Pubs/TechRpts/2017/EECS-2017-91.pdf Here is a link they did it with an Arduino: http://www.kk5jy.net/psk-modem-v1/ I used this "decoding BPSK data with arduino" as a search term and found lots of data. It has been a long time since I have done anything with BPSK, I hope this answers your question.

Gil
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  • It's funny you mention this - I actually have a 2012 edition still in its plastic! Just unwrapped it - hopefully BPSK hasn't changed much :) – Drewster Mar 11 '21 at 03:57
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This is not a direct answer to your question but just be advised that there are different considerations and circuitry for receivers that decode demodulate (digital) signals as opposed to radio circuits which must faithfully demodulate continuous (analog) signals. Linearity is a big consideration.

BHS
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