CXA2561Q Datasheet, PDF (15/20 Pages) Sony Corporation – Dolby B-C Type Noise Reduction System with Playback Equalizer Amplifier

CXA2561Q
5. Operating mode control method
The CXA2561Q has a Dolby NR mode select switch (NRMODE), Dolby NR switch (NRSW), mute switch
(MUTE SW), playback equalizer amplifier select switch (TAPESW), head input select switch (DRSW), music
sensor mode select switch (MSMODE) and music sensor switch (MSSW).
The operating modes for each switch are shown in the following table.
Pin No.
Pin name
15 NRMODE
16 NRSW
17 MUTESW
18 TAPESW
19 DRSW
20 MSMODE
21 MSSW
Pin voltage
Low (OPEN)
Dolby B type NR
Dolby NR OFF
MUTE OFF
70µs
PBIN FORWARD
G1
MS ON
High
Dolby C type NR
Dolby NR ON
MUTE ON
120µs
PBIN REVERSE
G2
MS OFF
Notes on Operation
1. DIREF pin resistance
The current on DIREF (Pin 25) is the reference for the Dolby NR static characteristic, playback equalizer
amplifier resistor 7kΩ/12kΩ and the comparator threshold value of the music sensor.
Use the resistor with high accuracy for connecting to the DIREF pin.
(The resistance accuracy of 2% <metal-oxide> is recommended.)
2. Dolby NR
The Dolby NR attack/recovery time is determined by the capacitance connected to TCH (Pins 8 and 23),
and TCL (Pin 9 and 22).
Use the parts, connected to these pins, with high accuracy and small temperature characteristics.
(The capacitance accuracy of 10% <film> is recommended.)
3. Playback equalizer amplifier
The playback equalizer amplifier characteristics are determined by the resistor connected between the IC
internal resistor and PBFB (Pins 31 and 40) and the capacitor connected between PBFB and PBTC (Pins 1
and 30). Use the parts which satisfies the accuracy required for the playback equalizer amplifier.
4. Music sensor
The resistance and capacitance connected to G2FB (Pin 11) and G1FB (Pin 12) determine the detection
level and high-frequency cut-off.
The response time is determined by the resistance and capacitance connected to MSTC (Pin 13).
Use the parts which satisfies the accuracy required for the music sensor.
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