PULSE MODULATED INFRARED DATA COMMUNICATIONS LINK

A pulse modulated infrared data communications link including a transmitter and receiver in which the data to be sent is encoded as a biphase modulated signal having bit-cell and mid-cell transitions. Each transition is encoded as a narrow pulse in a pulse modulated signal. The pulse modulated signal is used to activate an infrared optical transmitter for generating pulsed optical signals. At a receiver, an optical detector converts pulsed optical signals into pulsed electrical signals. The pulsed electrical signals are amplified and filtered and evaluated by a comparator to generate a pulsed digital signal. The pulsed digital signal is processed by a logic circuit to generate a biphase encoded signal for transmitting on a serial data line.