TLH5176 15

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FIGURE 15 Monaural Cascade Connection

FM STEREO

When using the DNR system with FM stereo as the audio

source it is important to eliminate the ultrasonic frequencies

that accompany the audio If the radio has a multiplex filter

to remove the ultrasonics there will be no problem

This filtering can be done at the output of the demodulator

before the DNR system or in the DNR system control path

Standard audio multiplex filters are available for use at the

output of the demodulator from several filter companies

Figure 16 shows the additional components L1 C15 and

C16 that are added to the control path for FM stereo appli-

cations The coil must be tuned to 19 kHz the FM pilot

frequency

TLH5176 16

FIGURE 16 FM Stereo Application

FOR FURTHER READING

Tape Noise Levels

1 ‘‘A Wide Range Dynamic Noise Reduction System’’

Blackmer ‘dB’ Magazine August-September 1972 Volume

6

8

2 ‘‘Dolby B-Type Noise Reduction System’’ Berkowitz and

Gundry Sert Journal May-June 1974 Volume 8

3 ‘‘Cassette vs Elcaset vs Open Reel’’ Toole Audioscene

Canada April 1978

4 ‘‘CCIRARM A Practical Noise Measurement Method’’

Dolby Robinson Gundry JAES 1978

Noise Masking

1 ‘‘Masking and Discrimination’’ Bos and De Boer JAES

Volume 39

4 1966

2 ‘‘The Masking of Pure Tones and Speech by White

Noise’’ Hawkins and Stevens JAES Volume 22

1 1950

3 ‘‘Sound System Engineering’’ Davis Howard W Sams

and Co

4 ‘‘High Quality Sound Reproduction’’ Moir Chapman Hall

1960

5 ‘‘Speech and Hearing in Communication’’ Fletcher Van

Nostrand 1953

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