cxa1897q Sony Electronics, cxa1897q Datasheet - Page 15

• Manufacturer Part Number: cxa1897q
• Description: Dolby B Type Noise Reduction System With Recording/playback Equalizer
• Manufacturer: Sony Electronics

1. Description of Control Mode
(1) Playback and recording equalizers
1) Playback equalizer (120µs/70µs)
2) Recording equalizer (Normal, CrO
3) Speed control
4) Recording mute (29 pin)
The muting function is achieved by varying the gain of the recording equalizer amplifier as with an electric
volume, depending on the DC voltage level supplied to the REC MUTE pin.
Mute ON/OFF and the AGC ON/OFF are interlocked.
Notes for executing the fader function
The recording mute and the AGC are interlocked and if the AGC is turned OFF, the AGC output level is
increased. Therefore, when the level of 3dB or more is input to the AGC to execute the fader function, the
natural characteristics cannot be obtained.
Take care of setting the input level to the AGC.
5) FP CAL (21 pin)
The standard setting resistance is 27k . However, fo (Hz) is reduced by increasing and increased by
reducing this resistance.
6) GP CAL (22 pin)
The standard setting resistance is 27k . However, the gain is increased by increasing or reduced by
reducing this resistance.
DECK AB
(15 pin)
Recording mute
Control voltage
B EQ (17 pin)
REC MODE
Playback equalizer
Recording equalizer
SPEED (20 pin)
Rec Mute
AGC
H B EQ control complied with
L
(A DECK)
GND VCL 0.5V
Normal (Type I)
120µs
L
Mute ON
A EQ (16 pin)
L
Normal speed
Normal speed
(A DECK)
Mute ON
L
70µs
OFF
H
2
, Metal)
–7dB attenuation
CrO
2
2.0V
(Type II)
A EQ control complied with
M
(B DECK)
1.7 times normal speed
1.7 times normal speed
—15—
120µs
L
B EQ (17 pin)
3.5V VCH Vcc
Mute OFF
Metal (Type IV)
H
Mute OFF
ON
(B DECK)
M/H
70µs
H
CXA1897Q