TLH5176

August 1989

LM832 Dynamic Noise Reduction System DNR

General Description

The LM832 is a stereo noise reduction circuit for use with

audio playback systems The DNR system is noncomple-

mentary meaning it does not require encoded source mate-

rial The system is compatible with virtually all prerecorded

tapes and FM broadcasts Psychoacoustic masking and an

adaptive bandwidth scheme allow the DNR to achieve 10

dB of noise reduction DNR can save circuit board space

and cost because of the few additional components re-

quired

The LM832 is optimized for low voltage operation with input

levels around 30 mVrms

For higher input levels use the LM1894

DNR

is a registered trademark of National Semiconductor Corporation

The DNR

system is licensed to Nat onal Semiconductor Corp under U S patent 3678416

and 3753159

A trademark and licensing agreement is required for the use of this product

Features

Y

Low voltage battery operation

Y

Non-complementary noise reduction ‘‘single ended’’

Y

Low cost external components no critical matching

Y

Compatible with all prerecorded tapes and FM

Y

10 dB effective tape noise reduction CCIRARM

weighted

Y

Wide supply range 15V to 9V

Y

150 mVrms input overload

Y

No royalty requirements

Y

Cascade connection for 17 dB noise reduction

Applications

Y

Headphone stereo

Y

Microcassette players

Y

Radio cassette players

Y

Automotive radiotape players

Application Circuit

Order Number LM832M See NS Package M14A

Order Number LM832N See NS Package N14A

TLH5176 1

FIGURE 1 Component Hook-up for Stereo DNR System

C1995 National Semiconductor Corporation

RRD B30M115Printed in U S A