Audio Scrambler and Sub-Audio Signalling Processor
CMX138A
3
Block Diagram
Transmit Functions
Sub-audio Signalling
Pre-programmed 51 Tone CTCSS
Encoder
Programmable CTCSS Tone Encoder
Programmable 23/24bit DCS Encoder
In-band signalling
Mux
Programmable In-band Encoder
MOD
Audio processing
MIC
Voice
Filter
Compressor
(Optional)
Pre-
Emphasis
(Optional)
Scrambler
(Optional)
Soft
Limiter
Channel
Filter
Receive Functions
Audio Processing
DISC
Voice
Filter
VBias
De-Scrambler
(Optional)
De-Emphasis
(Optional)
Expander
(Optional)
sw
AUDIO
Sub-audio signalling
Pre-programmed 51 Tone CTCSS Decoder
LPF
Programmable CTCSS Tone Decoder
Programmable 23/24bit DCS Decoder
In-band signalling
HPF
Programmable tone decoder
System Control
AVdd
VBias
AVss
DVdd
VDec
DVss
Clock/Xtal
XtalN
IRQN
RDATA
CSN
CDATA
SCLK
C-BUS
Interface
Power
control
Registers
Bias
Bias
Auxiliary Functions
Auxiliary System Clocks
Programmable PLL Clock
Clock O/P
I/O Configuration
Tx Enable
I/O
Rx Enable
Clock Select
Crystal
oscillator
Main clock
PLL
Auxiliary DAC
Ramp Profile RAM
DAC 1
DAC O/P
Auxiliary ADC
Thresholds
ADC
Averaging
sw
ADC I/P
Figure 1 Block Diagram
©
2010 CML Microsystems Plc
Page 6
D/138A/2
CMLMICRO [ CML MICROCIRCUITS ]
