Thanks.. so some of these are for sale... I looked but unsuccessfully. Back at it..
It was a surprise to hear the application potentially being up-complicated to use quadrature communication/modulation and did some looking.. The pulse trains are certainly offset in a manner reminiscent of quadrature modulation but I can't imagine anything is gained by actually using that. All the application needs is to count the pulses on the two channels (or just one actually) and pay attention to who peaks or zero-crosses or whatever first to establish direction. I have the iGaging caliper (which I can highly recommend for accuracy, repeatability and build quality) and did some looking into its digital output last year. It appears to encode the position value so all the pulse counting is internal. I think if I recall it's SPI or possibly I2C. It's feeling attractive right now to build a simple 2-port combiner though first I'd definitely want to probe the output of the glass scales and ensure my understanding (simple pulse counting via 90-deg-offset signals) is the case rather than combined with quadrature. I totally need yet another project
What kind of boat are you on in that picture if I can ask? Been under that bridge once and did not enjoy the chop even slightly.
CW