The CMX138 is an audio processor designed primarily for the market of analogue ‘leisure’ two-way radio products (FRS, MURS, PMR446 and GMRS). The product features a user-programmable frequency inversion half-duplex audio scrambler, a flexible audio processing path (consisting of companding, pre/de-emphasis and level setting), with concurrent audio and signalling operations handled by the integrated sub-audio signalling processor (selectable to CTCSS and DCS modes). Additional features of the CMX138 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 CMX138 is available in a 3.0V to 3.6V with flexible powersave modes, 28-pin (E1) TSSOP package.