CMX881 Baseband Processor IC for PMR and Trunked Radios

Features:

Standard CTCSS Tone Generation and Detection
Automatic Signal Scanning and IRQ on Detection of Valid Rx Signals
Tone Generation for Caller Recognition Tunes
Low Power Operation with Graduated Powersave
Programmable Signal Detection Thresholds
Aux ADC Available to Monitor Inputs
Programmable Selcall Codec
Meets ETS 300 086, MPT1327, PAA and ETS 300 230 Specs
Voice Processing Facilities: Tx and Rx
Path Gain Setting, Voiceband and Sub-Audio Filtering, Programmable Soft Limiter
C-BUS Serial Host Interface
Tx Interface for Single or Two-Point Modulation
DTMF Generation

Applications:

PMR Radio Systems
Trunked Radio Systems
Wireless Signalling

Packages:

CMX881D6 - 28-pin SSOP
CMX881E1 - 28-pin TSSOP

Supply Requirement:

2.7 to 5.5 V

Description
The CMX881 is a full-function half-duplex audio and signalling processor IC for both PMR and trunked radio systems and is implementable to complex and simple end-designs.

Under the control of the host µC, all voiceband requirements are catered for: Voiceband and Sub-audio filtering, Pre/de-emphasis and audio routing and global level setting with single or two-point modulation in the transmit path.

The combination of new and standard signalling functions of this product offer, under software control, increased functionality, versatility and privacy:
Standard Code CTCSS and DCS functions and selcall operation.

To cater for call setup and system signalling the CMX881 offers an embedded 1200/2400 bps MSK/FFSK freeformat modem with sync detection in the Rx path and MPT standard CRC operations in Tx/Rx modes.
With ultra low power requirements and graduated powersave, this product therefore requires a smaller, more low-power µC than existing PMR or trunked radio systems, is available in compact SSOP and TSSOP packages.

Block Diagram

The CMX881 is a full-function half-duplex audio and signalling processor IC for both PMR and trunked radio systems

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Baseband Processor IC for PMR and Trunked Radios Systems