CXA1911 SONY [Sony Corporation], CXA1911 Datasheet - Page 11

• Manufacturer Part Number: CXA1911
• Description: Dolby B/C Type Noise Reduction System with Playback Equalizer
• Manufacturer: SONY [Sony Corporation]

Description of Operation
1. Signal route
Op1 and Op2 are operational amplifiers.
Op1 composes the playback equalizer by attaching a resistor and a capacitor to PBFB pin, and a
capacitor to PBTC pin.
Op2 is an input selector and a LINEOUT amplifier. The gain is 24 dB.
The Dolby reference level is –6 dBm (LINEOUT).
The adjustment method of playback equalizer is described in the paragraph (3).
Note)
Usually the TAPEIN pin level is adjusted by attenuator connected to PBOUT pin.
The capacitance value connected to PBFB can be reduced by adjusting the resistance
connected to PBFB to match the PBOUT level.
With this method, the capacitance value can be reduced according to the amount that the
resistance value is increased even for the same cut-off frequency.
(These specifications use the latter method.)
F
PBIN
PBFB PBTC
R
Op1
PBOUT
NR ON
TAPEIN
—11—
Fig. 1
NR OFF
Op2
Dolby level
LINEOUT
(–6dBm)
20dB
20dB
4dB
NR
CXA1911Q