CML Microcircuits has an audio scrambler and sub-audio signalling processor which is intended for use in half duplex analogue two-way radios or family radio equipment, particularly suited to enhanced MURS, GMRS, PMR446 and FRS designs.

The IC is designed to provide a user programmable frequency inversion audio scrambler with signal processing functions, CTCSS, DCS and in-band tones, allowing comprehensive voice processing and tone control.
 
There are also improved limiter functions, enhanced CTCSS and DCS performance, a new input automatic gain control function, in-band tone operation enabled down to 288Hz, and improved audio compandor which enhances the performance of compressed signals.

Other features include an auxiliary ADC channel, auxiliary DAC interface with optional RAMDAC to facilitate transmitter power ramping, auxiliary system clock output and transmit output for single-point-modulation.

The CMX138A also includes a crystal clock generator, with buffered output, to provide a common system clock if required.
 
The CMX138A is available in a small, low-power (3.0V to 3.6V with flexible powersave modes), 28-pin (E1) TSSOP package.
 
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