Codan Radio MT-3 - Manual (Page 35)

MT-3 ANALOG RADIO SYSTEMS | USER GUIDE
Chapter 4: Analog System Block Diagrams Page 27
Figure 4-4: AM Base Station (or AM / FM Cross-band System) Block Diagram
AM RECEIVER
AM TRANSMITTER
CONTROLLER
RF IN
RF OUT
PRESELCTOR
LOCAL
OSCILLATOR
SQUELCH CIRCUITRY
IF AMP & DEMOD
RECOVERED FLAT AUDIO
AUDIO
PROCESSOR
RF POWER AMPLIFIER
1 KHz TONE @ -25.0 dBm = 30% MOD
AUXILIARY BALANCED
INPUT
1 KHz TONE @ 30% MOD = -8.0 dBm
AUXILIARY BALANCED
OUTPUT
AUDIO O/P (TO SYSTEM
REGULATOR SPEAKER)
1 KHz TONE @ 30% MOD
= 0 dBm
1 KHz TONE
@ 0 dBm
= 30% MOD
AUXILIARY
PTT
OPTICAL
ISOLATOR
BALANCED AUDIO
OPTICAL
ISOLATOR
COR
AUXILIARY
COR
OSCILLATOR
TIME OUT
TIMER
AUTOMATIC
LEVEL CONTROL
BALANCED AUDIO
BALANCED LEVEL
MODULATION
CONTROL
PTT
DISTRIBUTION AMP
CROSSBAND AUDIO LEVEL
SUMMING AMP
SQUELCH GATE
AGC
CONTROL
LOW LEVEL
AUDIO ADJUST
HIGH LEVEL AUDIO ADJUST
CROSSBAND
CONTROL
1 KHz TONE
@ 0.0 to +10.0 dBm
= 85% MOD
NOTE: FOR AN AM / FM CROSSBAND SYSTEM THE AM RX OR TX BLOCK WOULD BE REPLACED WITH AN FM RX OR TX BLOCK. (TWO AM MODULES ARE SHOWN)