Engine Speed Sensor

[turboman1]

Having some trouble reading the signal from the engine speed sensor to the PCM. Tried reading out DC voltage and frequency...got nothing for the DC voltage and the frequency was not correct at 587 hz (I would think it would be around 25 hz = 750 rpm taking into account the two pips on the damper).

Am I missing something or does the PCM just look for a square wave from the sensor and determine the frequency?

Thanks for the help
Adam