CMX838 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX838' PDF : 71 Pages View PDF
FRS/PMR446/GMRS Family Radio Processor
CMX838
6.3 CMX838 Architectural Overview
The CMX838 integrates all the audio processing, tone signaling processor, modulation, baseband clock and
synthesizer functions described in Section 6.2, along with several other important functions to reduce cost,
size and design time. Its main function blocks are identified below.
Audio Processing
+
Level
Control
Tone Signaling
Processor
XTAL Oscillator & Baseband
Clock Generation
clocks
RF Synthesizer and charge pump
Figure 25: CMX838 Main Function Blocks
The Tone Signaling Processor includes many features that are not provided by typical subaudio tone
processors.
6.4 Detailed CMX838 Architecture
A detailed diagram of the CMX838 is shown below with its five main sections identified. The C-BUS serial
interface, not a main section, provides a convenient I/O port through which an external µC can access and
control the CMX838’s many functions using a minimum of signals and circuit board area.
TONE SIGNALING
PROCESSOR
MICOUT 3
MICIN 4
-
+
Vbias
AUX I/O 2
preemph
LPF
AUDIO PROCESSING
HPF
BOUT AOUT
27 28
AIN
BIN
25 24
LIM
LPF
voltage ref
LEVEL CONTROL
deemph
RXOUT 23
RXIN 1
VDD 22
VSS 19
VBIAS 26
XTAL 12
XTAL 13
REFIN 11
+RFIN 9
-RFIN 8
VDD
VSS
Bias
+
-
Vbias
BPF
LPF
CTCSS encode
audio tone encode
1
0
CTCSS decoders
voltage
ref
RX Notone / TX Duration
timer
+
Vbias
Vbias
Vbias
0°/180°
phase
0°/180°
phase
CBUS
serial
interface
Baseband timing generation
divide
32/33
12 bit programmable
reference counter
programmable divider
phase
detect
lock
detect
voltage ref
charge
pump
CLOCK GENERATION
SYNTHESIZER & CHARGE PUMP
SVDD
SVSS
s
TXMOD1 21
TXMOD2 20
IRQ 15
RPLY DATA 16
CMD DATA 17
SERIAL CLOCK 18
CS 14
SVDD 7
SVSS 10
CPOUT 5
ISET 6
Figure 26: CMX838 Main Sections
2003 CML Microsystems Plc
47
D/838/8
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