SG-2000 MANUAL
129
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
(1). Microprocessor Assembly: This module can be broken
down to four different parts;
1)
MicroProcessor
2)
RAM
3)
ROM
4)
Communication port
This module is responsible for programming the VCO and to
control the tone frequencies generated.
(1) 11.94 MHz Master oscillator with oven: This module
generates the reference frequency for all transmit and
receive functions. The Oscillator must be set for ±1 Hz at the
highest operating frequency.
(2) VCOs: The VCOs produce the required frequencies to
modulate and mix the audio signal in the unit. There are
three VCOs in the unit to produce two IF frequencies in the
radio.
(3) PLLs: The PLLs work in conjunction with the
MicroProcessor to produce the required voltages used in the
VCOs. There are four PLLs in the radio, three for the VCOs
and one for the tone generator.
(4) Serial Logic Switches: These logic switches interface
the to analog controls throughout the radio. They control
the receive and transmit voltages, the output filters, and
high/low power control.
(5) Tone Generator: The tone generator is a serial
programmable divider controlled by the MicroProcessor to
produce an audio frequency based on the reference clock.