RAD Data comm T1 - Manual (Page 18)

Chapter 1 Introduction FOM-E1/T1 Installation and Operation Manual
1-4 Functional Description
Signal Conversion
Conversion of the electrical signal into an optical signal takes place by using an
infrared light-emitting diode or laser transmitter. At the opposite end of the fiber,
the optical signal is converted back into an electrical signal and amplified to the
required level.
Data/Clock Recovery
To recover data and clock from the signal, a Phase Locked Loop (PLL) circuit is
utilized. FOM-E1/T1 provides internal selection for the E1/T1 electrical interfaces.
Data Transfer
The optical signal is linked to the fiber-optic media and transmitted via the optical
link to the remote unit. A high sensitivity pre-amplifier and an AGC (Automatic
Gain Control) circuit enable the remote unit to receive the optical signal. The
output of the receiver is applied to the clock recovery circuit and the data
regeneration circuit, which in turn apply it to the electrical interface driving circuit.