Using a Quadrature Encoder as a clock at best precision possible

[UnionME]

I would like to use a Quadrature encoder as a clock for analog data acquisition. Currently, I am using only one line of the encoder and the clock "ticks" when the line goes high. This is only one quarter of the precision the quatrature encoder is capable of, since it can count from both lines when they go either high or low. I was wondering if I can get the counter to send a pulse everytime it increments and use that pulse train as my clock. This would increase my analog data acquisition frequency four fold.

[JaredA]

Hello,

It is not going to be possible to count both rising and falling edges with a single counter. You could route the A phase and B phase of your encoder to different counters to capture the different edges on the signals, but that will not help you in using this encoder as your clock source. What you may want to invest in is a quadrature clock converter. You can find more information on this at the following tutorial:

Using Quadrature Encoders with E Series DAQ Boards

Best,

Jared A

[njg]

Investing in a quadrature clock converter is probably the most straghtforward solution (I've personally used them many times). An alternative would be to feed the two encoder channels into an XOR gate and use the output for your trigger. While this only yields a 2x improvement, it's far better than just using one line.

I suppose that one could then configure two sets of counters for finite pulse train generation (one set for rising edges - one set for falling edges) and then OR the two outputs together for a 4x improvement, but that's using a lot of resources compared to utilizing a single quadrature clock converter chip.