CML Semiconductor Products
4-Level FSK Modem Data Pump
FX919A
D/919A/4 June 1996
Advance Information
1.0
Features
•
4-Level FSK Modulation
•
Half Duplex, 4800 to 19.2k bits/sec
•
Full Packet Data Framing
•
Flexible Operating Modes
•
Host Bus Interface
•
Low Power 3.3V to 5V Operation
•
24-Pin Small Form Package Option
1.1
Brief Description
The FX919A is a CMOS integrated circuit that contains 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 processor and the radio modulation/demodulation circuits to deliver
reliable two-way transfer of the application data over the wireless link.
The FX919A assembles application data received from the processor, adds forward error correction (FEC) and
error detection (CRC) information and interleaves the result for burst-error protection. After adding symbol and
frame sync codewords, it converts the packet into filtered 4-level analogue signals for modulating the radio
transmitter.
In receive mode, the FX919A performs the reverse function using the analogue signals from the receiver
discriminator. After error correction and removal of the packet overhead, the recovered application data is
supplied to the processor. Any residual uncorrected errors in the data will be flagged. A readout of the SNR
value during receipt of a packet is also provided.
The FX919A uses data block sizes and FEC/CRC suitable for applications which require the high-speed
transfer of data over narrow-band wireless links. The device is programmable to operate at most standard bit-
rates from a wide choice of Xtal/clock frequencies.
©
1996 Consumer Microcircuits Limited
CMLMICRO [ CML MICROCIRCUITS ]
