CTCSS/DCS/SelCall Processor
1. Block Diagram
3
R7
R6
MX828 PRELIMINARY INFORMATION
C3
R2
TX AUDIO
OUT
SELCALL TX TONE
GENERATOR
C4
C6
CTCSS / DCS / SELCALL TX
VSS
VBIAS
VDD
AUDIO RX
R3
RX AMP OUT
C5
R4
Input from
Demodulator
C7
C1 X1
R1
C2
RX AMP IN
-
VBIAS
+
RX AMP
XTAL/CLOCK
XTAL
SUB AUDIO
LPF
CLOCK
OSCILLATOR
AND
DIVIDERS
TX TONE
CTCSS TX TONE
GENERATOR
TX SUB
AUDIO
OUT
DCS CODE
GENERATOR
23 / 24 bits
RX
AUDIO
OUT
SUM
IN
SUM
OUT
SUMMING
AMP
-
+
VBIAS
MOD 1
IN
MOD 1
MOD 1
ENABLE
TRIM
MOD 2
GENERAL PURPOSE
TIMER
AUDIO BPF
6dB
ATTENUATOR
MOD 2
ENABLE
C - BUS
INTERFACE
AND
CONTROL
LOGIC
TRIM
COMMAND DATA
REPLY DATA
CS
IRQ
SERIAL CLOCK
CTCSS / DCS / SELCALL RX
ADC
ADC
CTCSS/SELCALL
TONE
DECODER
COMPARATOR
3-bit
DAC
COMPIN
DCS
EQUALIZER
FILTER
ADC
DCS
DECODER
CTCSS
FAST TONE
DETECTOR
CBUS
COMPOUT
A/D CAP2
TX TONE
A/D CAP1
CTCSS
PREDICTIVE
TONE DETECTOR
C9
C8
Figure 1: Block Diagram
VDD
R5
© 1997 MX•COM Inc.
www.mxcom.com Tele: 800 638-5577 336 744-5050 Fax: 336 744-5054
Doc. # 20480161.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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