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CML Microcircuits
COMMUNICATION SEMICONDUCTORS
FX/MX128
Audio Band Scrambler
D/128/2 January 2003
Provisional Information
Features
• Full-Duplex Audio Processing • On-Chip Filters • Carrier Rejection >55dB • Uses IF (10.24 MHz) Clock • Excellent Audio Quality • Low Power Operation (3.0V) • Battery Powered Portability
Applications
• Cordless Telephones • Wireless PBX • Two-Way Radio • Leisure Radio
(FRS, GMRS, MURS, PMR446)
1.1 Brief Description The FX/MX128 is a full-duplex frequency inversion scrambler designed to provide secure conversations. The Rx and Tx audio paths consist of the following:
1. A switched-capacitor balanced modulator with high baseband and carrier rejection. 2. A 3.3 kHz inversion carrier (injection tone). 3. A 3100 Hz lowpass filter. 4.