Baseband Processor IC for PMR and Trunked Radios
- 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
- PMR Radio Systems
- Trunked Radio Systems
- Wireless Signalling
- CMX881D6 - 28-pin SSOP
- CMX881E1 - 28-pin TSSOP
- 2.7 to 5.5 V
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 solutions, is available in compact SSOP and TSSOP packages.
Block Diagram
