BA3870 View Datasheet(PDF) - ROHM Semiconductor

Part Name

Description

Manufacturer

BA3870

BBS (bass boost system) for radio cassette players

ROHM Semiconductor 

Audio ICs

4. Bass boost control system

Bass boost control is as follows in Fig. 8.

BA3870

The comparator level and gain of each block are given by

the following equations.

Attenuation of ATT2:

: GATT2 = 20log

Gain of Amp E:

R13//R14

R12)R13//R14

(dB)

: GE = 20log R15)R16

R16

(dB)

Comparator level of COMP:

: VCOM = 20log ( VB S

R17 )

2

R17)R18

VB: DC voltage at BIAS OUT pin

(dBV)

If the volume output level at the beginning of control of the

low range signal system ATT1 is VBBS (dBV),

VBBS + GATT2 + GE = VCOM

In this way, bass boost control is carried out based on the

volume as shown in Fig. 9.

429

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