A Cartesian Feedback Loop (CFBL) Transmitter improves the efficiency and linearity of transmitters for non-constant envelope modulation systems.
The CMX998 is an integrated solution for a linear based Cartesian Feedback Loop (CFBL) transmitter.
Acting as a direct conversion quadrature mixer from I and Q to RF output, it provides the capability to linearise 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 differential inputs are ideal for direct connection to standard modems and interface ICs such as CML’s CMX7163 QAM Data Modem, CMX7164 Multi Mode Wireless Data Modem, CMX910 AIS Baseband Signal Processor and more!
Frequency Range: 30MHz to 1GHz
Wideband Noise: ‑148dBc/Hz
C-BUS (SPI Compatible) Serial Interface
Gain Control, Error Amplifier
Up-Converter Forward Path
Down-Converter for Feedback Linearisation
360 Degrees Loop Phase Shift Control
DC Offset Measurement Output
Open-Loop Function, Instability Detector
Linearisation Gains of 30dB or more Achievable
Flexible Digital Interface
TETRA/TETRA2 Terminals
APCO P25 Phase 2
Software Defined Radio (SDR)
Aviation Systems
Mobile Satellite Terminals
Linear Modulation Schemes: QPSK, pi/4 DQPSK, 8PSK, QAM, OFDM, F4FM