1Mbps discrete transceiver.

251

05:02:33

2017-11-19: Fixed output logic 0 level (twice)

20m CAT-5 driven ECL-style: with a long-tailed pair and emitter-followers. Receiver is 2 more long-tailed pairs putting out 5V logic levels. I'm in love with long-tailed pairs, LOL! They work wonders.

The data source represents ASCII 'u' in 8 bits with 1 start and 1 stop bit at 0-level: (0)01110101(0).

Drops bit(s) at 2Mbps -- I have much more respect for the people who developed 1Gbps Ethernet now! ECL too, my long-tailed pairs don't go fast.

One feature of this design bothers me a little bit: it requires a ground return as well as the twisted pair, which could be inconvenient. I wonder about noise on the ground plane too; it would mostly become common-mode noise, but difference between the actual value of the 2 resistors means some part of the noise may appear differentially across the inputs.

published 8 years ago

eekee

8 years ago

I gave my phone a good long shake, and the noise didn't corrupt the data. Yay! (Shaking my phone is 100 times easier than shaking my Kindle, and, uh, infinitely more reasonable than shaking my desktop. :)

eekee

8 years ago

Improvement: http://everycircuit.com/circuit/5035488064045056

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