CML Microcircuits
COMMUNICATION SEMICONDUCTORS
CMX138A
Audio Scrambler and
Sub-Audio Signalling
Processor
Provisional Issue
D/138A/2 November 2010
CMX138A: Audio Scrambler and Sub-Audio Signalling Processor with Auxiliary
System Clock, ADC and DAC for use in Analogue Radio Systems
Features
•
Programmable Audio Scrambler
•
Concurrent Audio/Signalling Operations
•
Full Audio-band Processing:
Pre and De-emphasis, Compandor,
Scrambler and Selectable 2.55/3 kHz Filters
•
Auxiliary ADC and Auxiliary DAC
•
C-BUS Serial Interface to Host µController
•
Two Analogue Inputs (Mic or Discriminator)
DAC Output
ADC Input
3.0V to 3.6V
•
Selectable Audio Processing Order
•
Sub-audio Signalling: CTCSS, DCS
•
Auxiliary System Clock Output
•
Tx Output for Single-point Modulation
•
Low-power (3.0V to 3.6V) Operation
•
Flexible Powersave Modes
•
Available in 28-pin TSSOP Package
Modulator
Discriminator
RF
GPIO
CMX138A
Audio Scrambler
and
Sub-Audio Processor
Built on
FirmASIC
®
technology
C-BUS
Host
µC
System Clock 1
Reference Clock
1
Brief Description
The CMX138A is a half-duplex, audio scrambler and sub-audio signalling processor IC for Analogue Two-
way Radio applications. This makes it a suitable device for the leisure radio markets (FRS, MURS,
PMR446 and GMRS).
This device provides a user programmable frequency inversion audio scrambler, companding and pre/de-
emphasis – performing simultaneous processing of Sub-audio and In-band signalling.
Other features include an auxiliary ADC channel and an auxiliary DAC interface (with optional RAMDAC,
to facilitate transmitter power ramping).
The device has flexible powersaving modes and is available in a 28-pin (E1) TSSOP package.
©
2010 CML Microsystems Plc
CMLMICRO [ CML MICROCIRCUITS ]
