An optical signal receiver system provides for five (5) signals, namely
VCC, Ground, RPM (Receiver input Power Monitor), Data, and Data Bar
outputs, using only the four external pins of a conventional TO-style can
package. To provide for five signals on only four pins, two of the output
signals are superimposed on each other in which one has a DC value (RPM)
and one has an AC value (Data or Data Bar). Once the combined signal
comes out of the TO can, the combined signal can be separated into two
separate signals using a capacitor which blocks the DC signal (Data or
Data Bar) and allows the AC signal to go through. The DC information is
then extracted by filtering the AC information from the combined signal
with a Current Sense Circuit.