We have a heidenhain RON285 encoder which uses the 1Vpp signaliing for "infinite precision." Essentially it outputs two differential Sin/Cos signals and the phase angle between them allows you to get extreme precision for the encoder angle. You still need to send the two signals through a comparator with hysteresis to essentially convert it to a quadrature encoder signal and count the pulses. The phase angle calculation gives you the fractional precision.
1) Has anybody ever used an NI DAQ card to read in the raw voltages and do the necessary calculations to convert the SinCos singal to a high-precision angle? If so, are you willing to share the code?
2) Can I do the SinCos --> Quadrature conversion on the card itself by forking off the two SinCos singals into two other channels and specify that those two channels are quadrature encoded singals or must I have external hardware do the comparator + hysteresis before inputting it into the card?
P.S.
I just found this piece of hardware which does exactly what I was describing in #2 above, can I get this same functionality by just using the DAQ card itself? http://www.motrona.com/sincos.html