Debugging the Turing-Welchmann Bombe - Alternate Approach?

RE: Debugging the Turing-Welchmann Bombe - Alternate Approach?

DAB — Tue, 17 Jan 2023 19:40:50 GMT

Interesting experiment.

RE: Debugging the Turing-Welchmann Bombe - Alternate Approach?

dougw — Tue, 17 Jan 2023 18:12:31 GMT

Interesting work on simulating the solution. Isolation amps are designed so the output matches the input analog signal, but depending on the technology used may have bandwidth and accuracy issues. Some use an open loop coupling, which can result in distortion. Some use a closed loop where the output is fed back through a second isolation channel which can result in limited bandwidth. Some use modulation through a transformer or capacitor, which can have limited bandwidth and increased noise. A good starting point is to determine voltage and bandwidth requirements to narrow down the search before looking at noise and phase delays etc.

RE: Debugging the Turing-Welchmann Bombe - Alternate Approach?

shabaz — Tue, 17 Jan 2023 16:36:12 GMT

Hi Andrew,

There's also analog optocouplers, which look pretty neat, such as HCNR200: https://uk.farnell.com/c/optoelectronics-displays/optocouplers/linear-optocouplers?st=hcnr200&showResults=true

It has 1 MHz bandwidth. It contains two photodiodes, so that one is used for linearizing. There's a low-cost circuit option in the datasheet that uses transistors, or there are op-amp options too:

There is a SPICE model in the downloads tab:

https://www.broadcom.com/products/optocouplers/industrial-plastic/specific-function/high-linearity-analog/hcnr200