CML Semiconductor Products

CTCSS/DCS/SELCALL Processor

FX828

© 2009 CML Microsystems Plc

D/828/4 August 2009

1.0

Features

Provisional Issue

• Fast CTCSS Detection

• Programmable Tone Decoder

• Full 23/24 Bit DCS Codec

• Programmable Comparator for RSSI

• Non-Predictive Tone Detection

• Programmable Modulator Drivers

• Low Power 3.3V/5V Operation

• Programmable Tone Encoders

• Variable Gain Audio Filter

• Full Duplex CTCSS and Selcall

1.1

Brief Description

The FX828 is an innovative CTCSS, DCS and Selcall Codec, designed for the latest generation of Land

Mobile Radio equipment. Designed to complement the FX829, the FX828 has many advanced features

which assist the operation of modern SUBAUDIO and INBAND based signalling systems. The FX828 is

electrically, physically and software compatible with the FX818 and FX829. It permits manufacturers to

add new features to their equipment with minimal design changes.

The FX828 incorporates a programmable tone decoder which can be set to respond to between 1 and 15

CTCSS or Selcall tones with minimum software intervention. In addition, a 'Fast' CTCSS detector can

respond to a single programmed tone in 60 ms, or can be used to provide an output if any CTCSS tone is

present at the detector input. Two high resolution tone encoders perform accurate generation of any

CTCSS or Selcall tone in current use. Full 23 or 24 bit DCS encoding and decoding complements the

CTCSS/Selcall line-up.

A timer is included which, for example, may be used for timing Selcall

transmissions and a comparator is provided to assist with carrier or RSSI monitoring. The device can

operate full duplex in all operating modes except for DCS.

The FX828 along with the FX818 and FX829 is offered in a choice of small SSOP, DIL and SOIC 24-pin

packages. It may be used with 3.0 to 5.5 volt supply.