DATA BULLETIN
CMX469A 1200/2400/4800bps
MSK Modem
Features
• Selectable Data Rates
1200/2400/4800 bps
• Full-Duplex MSK
• RX and TX Bandpass Filters
• Clock Recovery and Carrier Detect
Capabilities
• Pin Selected Xtal/Clock Inputs
1.008MHz or 4.032MHz
PRELIMINARY INFORMATION
Applications
• Radio and General Applications
• Data-Over-Radio
• PMR/Cellular Signaling
• Portable Data Terminals
• Narrowband Coax Data Channels
• Two Way Radio (MPT1327) Signaling
• Personal/Cordless Telephone
The CMX469A is a full-duplex pin-selectable 1200/2400/4800bps Minimum Shift Key (MSK) Modem for FM
radio links. The mark and space frequencies are 1200/1800, 1200/2400, and 2400/4800Hz respectively.
Tone frequencies are phase continuous; transitions occur at the zero crossing point. The use of a common
Xtal oscillator with a choice of two clock frequencies (1.008MHz or 4.032MHz) provides data-rate, transmit
frequencies, and RX/TX synchronization. The transmitter and receiver operate entirely independently
including individual section powersave functions.
The CMX469A includes on-chip circuitry for Carrier Detect and RX Clock Recovery, both of which are made
available at output pins. RX, TX and Carrier Detect circuits contain bandpass filters to provide high quality
signals to their respective paths. The carrier detect time constant is set by an external capacitor, which may
be selected to optimize performance in high-noise environments.
High sensitivity and good bit-error-rate performance can be achieved even under adverse signal conditions.
The CMX469A operates with a 3.0V to 5.5V supply and is available in the following packages:
24-pin TSSOP (CMX469AE2), 20-pin SOIC (CMX469AD3), and 22-pin PDIP (CMX469AP6).
©1999 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480191.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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