CMX998 Cartesian Feed-back Loop Transmitter

CMX998

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CMX998 Cartesian Feed-back Loop Transmitter Features:

Frequency Range 100MHz to 1GHz
Wide Band Noise 148dBc/Hz
C-BUS (SPI compatible) Serial Interface
Gain Control
Error Amplifier
Up Converter Forward Path
Down Converter for Feedback Linearisation
360° Loop Phase Shift Control
DC Offset Measurement Output
Open Loop Function
Instability Detector
Flexible Digital Interface

Applications
TETRA Terminals
TETRA 2 Terminals
APCO P25 Phase 2
Aviation Systems
Mobile Satellite Terminals
Linear Modulation Schemes: QPSK, ð/4-DQPSK, 8PSK, QAM, OFDM, F4FM, etc.
Direct Interface to CMX981 / CMX980A

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 linear transmitter. Acting as a direct conversion quadrature mixer from I and Q to RF output, it provides the capability to linearize the Power Amplifier (PA) via feedback from the PA's output. Included are forward and feedback paths; local oscillator circuitry including loop phase control; an instability detector and uncommitted op-amps for input signal conditioning.
The device operates from a single 3.3V supply over a temperature range of -40°C to +85°C and is available in a 64 pin VQFN (Q1) package.

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