High Performance Automotive Sonar Intrusion – Data Sheet

AS8413

March 2001

Page 2 of 15

PRE-

AMP

BAND-PASS

FILTER

AGC

ENVELOPE

DETECTOR

A / D

CONVERTER

D S P

DISCRIMINATOR

MODULATOR /

DRIVER

CONTROL

LOGIC

OSCILLATOR

SIGNALLING

VCAP

SAS

SENS 1

SENS 0

ALEN

LED

WARN

ALARM

SEL40K

OSCIN

OSCOUT

TX1

TX2

RX

COSC

MODE

SYNC

Key Features

• True sonar/pulse-echo operation

• Master/slave synchronization

• Wide dynamic range

• Programmable sensitivity levels

• Self-adaptive to vehicle interiors

• Self-adaptive to temperature and environmental changes

• High sensitivity to intrusion

• Immunity to false alarms

• Detection of sabotage attempts

• Compatible with standard 40 kHz ultrasonic transducers

• Specific for systems with multiple transducers

• No adjustments needed at factory or at field

• Few external components

• Time reference: external clock or oscillator based on crystal/ceramic resonator

• Built-in self-test

• Internal power-on-reset

• Advanced CMOS technology

• Low power consumption: 0.65 to 1.0 mA

• Operation between -40°C and +85 °C

• Available in 24-pin DIP and 24-pin SOIC package

General Description

The AS8413 is a signal processing IC designed to implement reliable, high-performance

sonar intrusion detectors. It generates short 40 kHz bursts to feed an ultrasonic trans-

ducer. The resulting sonar waves are reflected on the vehicle interior and the echoes are

received by another transducer. Inside the AS8413, the electrical signal is first submitted to

an analog conditioning circuit, then it is digitized and processed by a DSP, whose output is

analyzed by a discriminator based on fuzzy-logic techniques. Thus, true intrusion condi-

tions can be discerned from natural phenomena and other allowable disturbances.

Synchronization between the sonar waves from 2 or more pairs of transducers is made

possible by means of a master/slave configuration. Each pair is controlled by a AS8413 IC.

No adjustments are necessary at factory or at the field, as the AS8413 is self-adaptive to

the physical and environmental conditions. Compact and EMI-resistant intrusion detectors

are made possible, due to the small number of components.

Block Diagram