COMMUNICATION SEMICONDUCTORS
MX919B
4-Level FSK Modem Data Pump
PRELIMINARY INFORMATION
DATA BULLETIN
Features
•
•
•
•
•
•
•
•
4-Level Root Raised Cosine FSK Modulation
Half Duplex, 4800 to 19.2kbps
Increase Channel Bit Rate/Hz
Full Data Packet Framing
Impulse and NRZ Signal Modes
Enhanced Performance in Noisy Conditions
Error Detection and Error Correction
Low Power 3.3V/5.0V Operation
Applications
•
•
•
•
•
Wireless Data Terminals
Two Way Paging Systems
Digital Radio Systems
Wide Area Wireless Data Broadcasts
Point to Point Wireless Data Links
RADIO
MODULATOR
RF
DISCRIMINATOR
ANALOG RX
ANALOG TX
MX919B
MODEM
DATA
PUMP
DATA AND
CONTROL BUS
HOST
µ
C
SYSTEM
APPLICATION
PROCESSING
The MX919B is a low voltage CMOS device containing all of the baseband signal processing and Medium
Access Control (MAC) protocol functions required for a high performance 4-level FSK Wireless Packet Data
Modem. It interfaces with the modem host
µC
and the radio modulation/demodulation circuits to deliver
reliable two-way transfer of the application data over a wireless link.
The MX919B assembles application data received from the host
µC,
adds forward error correction (FEC) and
error detection (CRC) information, and interleaves the result for burst-error protection. After automatically
adding symbol and frame sync codewords, the data packet is converted into filtered 4-level analog signals for
modulating the radio transmitter.
In receive mode, the MX919B performs the reverse function using the analog signals from the receiver
discriminator. After error correction and removal of the packet overhead, the recovered application data is
supplied to the host
µC.
CRC detected residual uncorrected data errors will be flagged. A readout of the
SNR value during receipt of a packet is also provided.
The MX919B uses data block sizes and FEC/CRC suitable for applications where high-speed transfer of data
over narrow-band wireless links is required. The device is programmable to operate at standard bit rates from
a wide range of Xtal/clock frequencies.
The MX919B may be used with a 3.0V to 5.5V power supply and is available in the following package styles:
24-pin SSOP (MX919BDS), 24-pin SOIC (MX919BDW), 24-pin PLCC (MX919BLH), and 24-pin PDIP
(MX919BP).
©2001 MX•COM, INC.
www.mxcom.com
Tele: 800 638 5577 336 744 5050
Fax: 336 744 5054
Doc. # 20480170.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
All trademarks and service marks are held by their respective companies.
CMLMICRO [ CML MICROCIRCUITS ]
