SM5950AM

NIPPON PRECISION CIRCUITS INC.—14

Deemphasis (DEEM)

Basic deemphasis filters are realized using analog circuit configurations. Here, an IIR digital deemphasis filter

configuration faithfully reproduces the gain and phase characteristics of an analog deemphasis filter. The filter

coefficients are set by pins FS0 and FS1 for 3 input sampling frequencies (fsi) of 44.1kHz, 48.0kHz, and

32.0kHz.

Deemphasis ON/OFF

Deemphasis filter coefficient selection

The deemphasis filter is selected by pins FS0 and FS1.

Deemphasis filter characteristics

DEEM

Deemphasis

L

OFF

HON

FS0

FS1

fsi

L

L

44.1kHz

H

L

44.1kHz

L

H

48.0kHz

H

H

32.0kHz

Figure 2. Deemphasis filter frequency characteristics

Figure 3. Deemphasis filter phase characteristics

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

10

100

1000

10000

100000

Frequency [Hz]

44.1kHz

48kHz

32kHz

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

100

1000

10000

100000

Frequency [Hz]

44.1kHz

48kHz

32kHz