RFL Electronics 9780 - System Theory of Operation

RFL 9780 RFL Electronics Inc.
April 8, 2003 2-16 (973) 334-3100
2.8.11 CHASSIS
Most RFL 9780 terminals consist of a single chassis, which houses all transmitter and receiver
modules. Each chassis contains a motherboard, which provides all electrical interconnections between
its modules and a few coax cables for RF signals. Coaxial connectors on the rear panels are used to
connect the RFL 9780 to the line tuning equipment.
Isolation boards mounted to the rear panel of each contains optically-isolated input circuits, isolated
output drivers, output relays, and high-voltage and transient suppression circuits. Terminal blocks on
the isolation boards extend out of the rear panel, and are used to connect external equipment to the RFL
9780. Section 20 of this manual provides additional information on the chassis, motherboards, and
isolation boards.
2.8.12 ACCESSORY EQUIPMENT
Other circuit card modules and assemblies are available to enhance the operation of the RFL 9780
terminal, or to adapt it to special applications. If any accessory equipment was furnished with your
system, an Instruction Data Sheet for each item will appear in Section 21 of this manual.
2.9 SYSTEM THEORY OF OPERATION
The RFL 9780 has four functional blocks: the transmitter section; the receiver section; the logic (or
control) functions; and, the sequence of events functions. All of these functions are tied together by the
chassis (with motherboard) and powered by the power supply.
2.9.1 TRANSMITTER SECTION
The function of the transmitter section is to provide the desired carrier frequency, at the desired power
level at the transmitter port. For clarity, the functions which determine the desired output frequency
and power level are discussed in Section 8. The transmitter section consists of three basic modules, the
Transmitter Module, the Power Amplifier Module, and the Output Filter Module. This may also be
followed by a hybrid.
The Transmitter Module generates a clean, precise, carrier at the desired frequency and level. A single
module is capable of transmitting three frequencies, a center frequency, a shift-down, and a shift-up
frequency. The two shift frequencies may be independently selected by the user.
The transmitter may be instructed to generate one of three carrier levels (which correspond to 1, 3, and
10 watts transmit power after the Power Amplifier). (Although rarely used, the module also has
provisions for modulating the carrier envelope to a supplied voice signal and a “reserve” feature which
reduces the output power by a factor of 10.) See Section 8 for more information about the Transmitter
Module.