CMX980AL7 Просмотр технического описания (PDF) - MX-COM Inc
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CMX980AL7 Datasheet PDF : 82 Pages
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COMMUNICATION ICs
DATA BULLETIN
CMX980A
Digital Radio
Baseband Processor
Advance Information
Features
• RRC Filters for both Tx and Rx
• 4 x 10-Bit D-A and 4 Input 10-Bit A-D
• π/4 DQPSK Modulation
• Transmit Output Power Control
• 2 x 14-Bit Resolution Sigma Delta D-A • Low Power 3.0 - 5.5Volt Operation
• 2 x 16-Bit Resolution Sigma Delta A-D • Effective Power down Modes
A-D
Vocoder
CMX980A
Channel Coding.
TDMA Frame
Formatting
RRC
p /4
DQPSK
RRC
D
A
D
A
TETRA Transmitter
RF Modulator
'I'
90° S
'Q'
Cartesian Loop
Linear PA
Carrier
Oscillator
Local
Oscillator
RF Amp
Oscillator
Bandpass
Filter
IF Amp
TETRA Receiver
D-A
Voice
Decoder
p /4 DQPSK
Demodulator,
Channel Decoder,
TDMA Framing
Example: CMX980A in a TETRA System Application
'I'
90°
'Q'
CMX980A
RRC
RRC
A
D
A
D
CMX980A
D
A
D
A
A
D
A
D
TETRA
Auxiliary
Functions
'I'
'Q'
This device is intended to act as an interface between the analog and digital sections of a Digital Radio
System, and performs many critical and DSP-intensive functions. The chip is designed with the necessary
capability to meet the requirements for use in both mobile and base station applications in Terrestrial Trunked
Radio (TETRA) systems, but the architecture is sufficiently flexible to allow use in other systems.
The transmit path comprises all the circuitry required to convert digital data into suitably filtered analog
I and Q signals for subsequent up-conversion and transmission. This includes digital control of the output
amplitudes, digital control of the output offsets and fully programmable digital filters: default coefficients
provide the RRC response required for TETRA.
The receive section accepts differential analog I and Q signals at baseband and converts these into a suitably
filtered digital form for further processing and data extraction. A facility is provided for digital offset correction
and the digital filters are fully programmable with default coefficients providing the RRC response required for
TETRA.
Auxiliary DAC and ADC functions are included for the control and measurement of the RF section of the radio
system. This may include AFC, AGC, RSSI, or may be used as part of the control system for a Cartesian
Loop.
The CMX980A requires a 3.0V to 5.0V supply and is available in the following packages: 44-pin PLCC
(CMX980AL6) and 44-pin QFP (CMX980AL7).
2000 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. 20480201.001
4800 Bethania Station Road, Winston-Salem, NC 27105-1201, USA
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