CML Semiconductor Products
PRODUCT INFORMATION
FX506
Features/Applications
Full Rx and Tx Filtering to
CEPT Standards
Digital Control of Volume,
Noise Squelch and R.S.S.I.
Tx VOGAD Circuitry
Serial
µP
Control of ALL Chip
Functions
Deviation Limiter
Rx
EXTERNAL AUDIO
PROCESSES
Mobile Radio Audio Processor
Publication D/506/3 July 1994
Military/Marine and Mobile
Radio Applications
FM/AM/SSB Applications
16-kbit Data and Voice Scrambler
Compatible
Low-Power 5-Volt CMOS
Process
Tx
RECEIVER
AUDIO
4.0MHz
RSSI
MODULATION
CTCSS and DATA
Tx AUDIO
MIC.1
REF.
TRANSMITTER
VCO
FX506
Single-Chip
Audio Processor
SERIAL
SQUELCH/CARRIER
DETECT
BUS
SYSTEM
UP
FX506
PA
MIC.2
HIGH
SQUELCH
LOW
µP
VOLUME
DOWN
Brief Description
The FX506 is a
µProcessor-controlled,
single-chip
device containing ALL the circuit elements necessary
to perform the audio functions of a mobile (or portable)
radio system.
On-chip signal paths include: speech-band/pre-
emphasis filters, variable gain/attenuation stages,
voice-compression and deviation limiter circuitry.
Each function in the signal path can be addressed or
by-passed ––
providing “real-time,” dynamic control
––
by the
µProcessor.
This half-duplex device comprises
two separate audio signal paths.
The Pre-Process Path
performs filtering and level
adjustment on audio (Rx or Tx) for use in auxiliary
systems such as “Frequency Inversion Scrambling,”
“Sub-Audio” tone or “In-Band” data signalling. This path
is output at the “Pre-Process Audio Output” pin. If no
external processes are being used this output should
be connected to the “Pre-process Audio Input” pin.
The Post-Process Path
can adjust and prepare
the input audio for output to the chosen transmitter
driver or loudspeaker amplifier.
Suitably software configured, the FX506, which can
operate on voice, direct-digital or tone-data and sub-
audio frequencies, is compatible with FM, AM and
SSB type transceivers. Digital gain elements are
provided on-chip for dynamic control and balance of
signal-path levels during manufacturing, test and
operation.
System Squelch,
a separate path, is sourced from
either the incoming signal or Received Signal
Strength Indication (R.S.S.I.) from the radio circuitry.
The FX506, a low-power 5-volt CMOS device, is
available in 24-pin/lead plastic DIL and SMD
packages.
CMLMICRO [ CML MICROCIRCUITS ]
