What is difference between HTL and TTL?

Answer 1

HTL, TTL performance is very similar: the only difference between the two is the type of electronics used and, as a result, different operating voltage. Typical counts of pulse encoders are 2,048 or 4,096, but there are lower and higher count devices available. Unlike other encoder types, the device produces a discrete output pulses on two tracks, A and B, at a single voltage level. A and B tracks are offset by 90 degrees. A combination of two tracks allows control electronics to determine the motor direction and, by counting rising and falling edges of each pulse, to attain a resolution 4x the pulse count. A third channel, Z pulse, is commonly utilized to indicate the zero mark. TTL (5V) electronics can be considered to have better immunity to electronic noise, because each track has two signals, A and A not, which are inverted with respect to each other. By transmitting a differential signal like that allows control electronics to reject the noise that may be present on both signals at the same time.