KA9270

AUDIO FILTER

APPLICATION INFORMATION

1. BUFFER

Fig. 3

It is used for impedance matching, between D/A converter output and de-emphasis input.

2. DE-EMPHASIS

a) De-emphasis operation condition

b) De-emphasis characteristic at the de-emphasis ON

Fig. 4 Equevalent Circuit of De-emphasis ON Mode

The de-emphasis charcteristics is dependent on the external parts value.

+

-

INPUT

(from D/A Converter

Output)

to De-emphasis input

Control Input

De-emphasis Operation

High

ON

Low

OFF

+

-

Vi

R6

R5

R4

Vo

C1

Av