I am building a circuit board to listen to quadrature encoder signals from a motor controller and send these signals on to an FPGA that will be used to count the pulses and direction. The signals coming out of my motor controller are:

* Phase A: A and !A
* Phase B: B and !B
* Phase C: C and !C (origin indicator)

In other words, each phase sends out two signals that are the opposite of one another at all times. I have used Quad EIA-422/423 (MC3486) line receivers to convert differential voltage signals into TTL signals, but is this the correct component for converting each phase from two signals to a single TTL signal? If not, is there a similar IC that will do the trick?

Thanks!

**EDIT:** It looks like I was treating these signals correctly. I was a little confused on the definition of "differential voltage" as it applies to the line receivers I am using (MC3486). Basically when A is `high` and !A is `low`, my line receiver outputs a `high` on the TTL channel. When A is `low` and !A is `high`, it outputs a `low` on the TTL channel. This is what I wanted it to do; I was concerned that I had misinterpreted the meaning of differential voltage.