FULL-DUPLEX SCRAMBLER FOR CORDLESS TELEPHONES

Figure 1 - Simplified Signal Paths

3) A 3.3 kHz inversion carrier (injection tone).

4) A 14

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.

MX118P

MX118DW

(16 pin PDIP)

(SOIC-16)

Features

Features

Features

Features

Features

Full-Duplex Audio Processing

Full-Duplex Audio Processing

Full-Duplex Audio Processing

Full-Duplex Audio Processing

Full-Duplex Audio Processing

On-Chip “Brick-wall” Filters (300-3000 Hz)

On-Chip “Brick-wall” Filters (300-3000 Hz)

On-Chip “Brick-wall” Filters (300-3000 Hz)

On-Chip “Brick-wall” Filters (300-3000 Hz)

On-Chip “Brick-wall” Filters (300-3000 Hz)

Low Voltage CMOS

Low Voltage CMOS

Low Voltage CMOS

Low Voltage CMOS

Low Voltage CMOS

High Baseband and Carrier Rejection

High Baseband and Carrier Rejection

High Baseband and Carrier Rejection

High Baseband and Carrier Rejection

High Baseband and Carrier Rejection

Excellent Audio Quality

Excellent Audio Quality

Excellent Audio Quality

Excellent Audio Quality

Excellent Audio Quality

ECPA* Qualified Voice Protection

ECPA* Qualified Voice Protection

ECPA* Qualified Voice Protection

ECPA* Qualified Voice Protection

ECPA* Qualified Voice Protection

Applications

Applications

Applications

Applications

Applications

Cordless Telephones & Wireless PBXs

Cordless Telephones & Wireless PBXs

Cordless Telephones & Wireless PBXs

Cordless Telephones & Wireless PBXs

Cordless Telephones & Wireless PBXs

Battery Powered Portability

Battery Powered Portability

Battery Powered Portability

Battery Powered Portability

Battery Powered Portability

Description

Description

Description

Description

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:

2) A balanced modulator with high baseband and carrier

rejection.

* Electronics Communications Privacy Act (Title 18 US Code 2510 et seq.).

MX118