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RF Quadrature Transceiver circuit based on CMX991

Published on Nov 24 2010 // Wireless Receiver Circuits


RF Quadrature Transceiver circuit based on CMX991.

The CMX991 is a single-chip, high performance, RF transceiver that provides the core functions required
to implement a full-featured radio transmitter and receiver. It operates from 100MHz to 1GHz. It supports multiple modulation types
and bandwidths with a single radio design.

The halfduplex CMX991 integrates Tx modulators, Rx demodulators, IF PLL and IF VCO subsystems to minimise
the external circuits needed when implementing a complete transceiver.

The Tx path includes an I/Q modulator which generates modulation at the IF frequency,
then is translated to the final RF frequency by an integrated image-reject up-converter system.

The Rx path includes an integrated 1st Rx mixer having two outputs to support two external 1st IF filter
choices, then an integrated 2:1 input mux followed by VGA and wideband signal level measurement
functions, to support AGC implementation.

The device specification are as follows:
    1. Operate from a single 3.3V supply
    2. Temperature range of -40°C to +85°C
    3. 48-pin VQFN (Q3) packages.

The applications include:

• Analogue/digital multimode radio
• Software Defined Radio (SDR)
• Portable, mobile and base station terminals
• Data telemetry modems
• TETRA (CMX992)
• ETSI: EN 300 113, EN 301 166, EN 302 561,EN 300 220, TS 102 361 (DMR)
• Automatic Identification System (AIS) transponders
• Constant envelope and linear modulation
• Compatible with CMX998 (CMX992 only)
• Narrowband: e.g. 25kHz, 12.5kHz, 6.25kHz
• Wideband: up to 2MHz
• APCO Project 25 (P25) Phase 1 and Phase 2 TDMA: TIA-102.CAAB
• Satellite communications