LM1894M

Manufacturer Part NumberLM1894M
DescriptionDynamic Noise Reduction System DNR
ManufacturerNational Semiconductor
LM1894M datasheet
 


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LM1894
Dynamic Noise Reduction System DNR
General Description
The LM1894 is a stereo noise reduction circuit for use with
audio playback systems. The DNR system is non-
complementary, meaning it does not require encoded source
material. The system is compatible with virtually all prere-
corded 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 compo-
nents required.
Features
n Non-complementary noise reduction, “single ended”
n Low cost external components, no critical matching
Typical Application
*R1 + R2 = 1 kΩ total.
See Application Hints.
Order Number LM1894M, LM1894N, or LM1894MT
See NS Package Number M14A, N14A, or MTC14
FIGURE 1. Component Hook-Up for Stereo DNR System
DNR
®
is a registered trademark of National Semiconductor Corporation.
The DNR
®
system is licensed to National Semiconductor Corporation under U.S. patent 3,678,416 and 3,753,159.
Trademark and license agreement required for use of this product.
© 2004 National Semiconductor Corporation
n Compatible with all prerecorded tapes and FM
n 10 dB effective tape noise reduction CCIR/ARM
weighted
n Wide supply range, 4.5V to 18V
n 1 Vrms input overload
Applications
n Automotive radio/tape players
n Compact portable tape players
n Quality HI-FI tape systems
n VCR playback noise reduction
n Video disc playback noise reduction
DS007918
April 2002
®
00791801
www.national.com

LM1894M Summary of contents