Document
CML Microcircuits
COMMUNICATION SEMICONDUCTORS
CMX998
Cartesian Feed-back Loop Transmitter
D/998/13 August 2015
Features
Applications
Frequency Range 30MHz to 1GHz
TETRA Terminals
Wide Band Noise –148dBc/Hz
TETRA 2 Terminals
C-BUS (SPI compatible) Serial Interface APCO P25 Phase 2
Gain Control
Aviation Systems
Error Amplifier
Mobile Satellite Terminals
Up Converter Forward Path
Linear Modulation Schemes:
Down Converter for Feedback
QPSK, /4-DQPSK, 8PSK, QAM,
Linearisation
OFDM, F4FM, etc.
360° Loop Phase Shift Control
Direct Interface to CMX981, CMX980A
DC Offset Measurement Output
and CMX7163/CMX7164
Open Loop Function
Instability Detector
Flexible Digital Interface
1 Brief Description
A Cartesian Loop improves the efficiency and linearity of transmitters for non-constant envelope modulation systems.
The CMX998 is an integrated solution for a Cartesian Feedback Loop based linea.