CMX981
CML Microcircuits
COMMUNICATION SEMICONDUCTORS
D/981/3 September 2003
Advanced Digital Radio
Baseband Processor
Advance Information
Features
•
Programmable Digital Tx and Rx Filters
•
High Performance Codecs
•
Radio Rx: 2 x 16-Bit Sigma Delta ADC
•
Radio Tx: 2 x 14-Bit Sigma Delta DAC
•
Auxiliary: 6 x 10-Bit ADC
•
Auxiliary: 4 x 10-Bit DAC
•
Voice: 14-Bit Linear with Digital Filter
• π
/4 DQPSK and Other Modulations
•
Full Duplex Operation
•
C-BUS and 3 Fast Serial Bus Interfaces
•
Low Power for Portable Terminals
•
2.5V Supply With 3.3V Tolerant I/O
•
130mW Speaker Amplifier (8Ω load)
Ω
•
16.5mW Earpiece Amplifier (32Ω load)
Ω
CMX981
ADC
Voice Filter
Voice Coder
Channel Coding
TDMA Frame
Formatting
π
/4
DQPSK
CMX981
DAC
RRC
RF Modulator
Cartesian Loop
Linear Power Amp
90
°
E
DAC
RRC
TETRA Transmitter
Carrier
Oscillator
Local
Oscillator
Oscillator
CMX981
90
°
DAC
ADC
RF Amp
Band Pass
Filter
IF Amp
DAC
ADC
CMX981
CMX981
DAC
Voice Filter
Voice Decoder
π
/4 DQPSK
Demodulator
Channel Decoder
TDMA Framing
ADC
RRC
ADC
RRC
TETRA
Auxiliary
Functions
TETRA Receiver
1.
Brief Description
The CMX981 Advanced Digital Radio Baseband Processor is a combination codec/processor that
interfaces analogue and digital sections of a Digital Radio System and performs critical DSP-
intensive functions. The device supports portable, mobile and base station TErrestrial Trunked
RAdio (TETRA) system applications and is also sufficiently flexible for use in other demanding
digital radio systems.
The CMX981 transmit path comprises all functions required to convert digital ‘symbol’ data into
suitably filtered analogue I and Q signals for external up-conversion and transmission. This
includes digital control of output amplitudes and offsets and fully programmable digital filters.
Default coefficients provide the root raised cosine (RRC) response required for TETRA.
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©
2003 CML Microsystems Plc
CMLMICRO [ CML MICROCIRCUITS ]
