MX118 Datasheet, PDF (1/7 Pages) CML Microcircuits – FULL-DUPLEX SCRAMBLER FOR CORDLESS TELEPHONES

MX118
FULL-DUPLEX SCRAMBLER FOR CORDLESS TELEPHONES
Features
Full-Duplex Audio Processing
On-Chip “Brick-wall” Filters (300-3000 Hz)
Low Voltage CMOS
High Baseband and Carrier Rejection
Excellent Audio Quality
ECPA* Qualified Voice Protection
Applications
Cordless Telephones & Wireless PBXs
Battery Powered Portability
MX118P
(16 pin PDIP)
MX118DW
(SOIC-16)
Description
The MX118 is a full-duplex frequency inversion scram-
bler that secures cordless telephone conversations. The
two audio paths, C1 and C2, are identical and independ-
ent. Each consists of the following:
1) A 10^th order lowpass filter cut off at 3.1 kHz.
2) A balanced modulator with high baseband and carrier
rejection.
3) A 3.3 kHz inversion carrier (injection tone).
4) A 14^th order bandpass filter (300-3000 Hz).
5) Input op-amps with externally adjustable gain.
The MX118 uses CMOS switched-capacitor filter
technology and operates from a single supply in the range
of 3.0 V to 5.5 V. The inversion carrier's frequency and
filter switching clock are generated on-chip using an
external 4.433619 MHz crystal or clock input.
Figure 1 - Simplified Signal Paths
* Electronics Communications Privacy Act (Title 18 US Code 2510 et seq.).