Tait TB8100 Service Manual

34 Reciter Circuit Description TB8100 Service Manual
© Tait Electronics Limited September 2006
Responsibilities
The RISC communicates with the DSP’s shared memory via a host port
interface. It loads the DSP code and monitors and controls the following
DSP operations:
■ receive path
■ transmit path
■ crosspoint switches
■ power supplies
■ PA Key output.
The RISC controls the frequency generation subsystem. It detects an
external reference source and selects internal or external reference. It also
programs, and handles out-of-lock signals for, the following synthesizers:
■ 12.8MHz external reference synthesizer
■ 40MHz digital clock synthesizer
■ receiver synthesizer
■ exciter synthesizer.
The RISC communicates with the control panel via I
2
C bus to:
■ read the button states
■ read the microphone PTT state
■ control the LEDs
■ turn the speaker amplifier on and off
■ turn the microphone amplifier on and off.
The following signals go via the control panel for signal conditioning:
■ Service Kit communication via the RS-232 interface
■ fan-good indication (front panel fans).
Note that the volume control on the control panel is analogue only and is
not controlled by the RISC.
The RISC communicates with the other modules in the subrack via I
2
C in
order to:
■ verify that they are present
■ write configuration settings
■ read their current status.
The RISC subsystem communicates with the system interface board via SPI
to:
■ set input and output gains
■ mute and unmute outputs
■ read digital inputs
■ write digital outputs.

Tait TB8100 Specifications

General

Brand	Tait
Model	TB8100
Category	Accessories
Language	English