cxa2561q Sony Electronics, cxa2561q Datasheet - Page 15

• Manufacturer Part Number: cxa2561q
• Description: Dolby B-c Type Noise Reduction System With Playback Equalizer Amplifier
• Manufacturer: Sony Electronics

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.
Notes on Operation
1. DIREF pin resistance
2. Dolby NR
3. Playback equalizer amplifier
4. Music sensor
Pin No.
The current on DIREF (Pin 25) is the reference for the Dolby NR static characteristic, playback equalizer
amplifier resistor 7k /12k 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.)
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.)
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.
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.
15
16
17
18
19
20
21
NRMODE
NRSW
MUTESW
TAPESW
DRSW
MSMODE
MSSW
Pin name
PBIN FORWARD
– 15 –
Dolby B type NR
Dolby NR OFF
Low (OPEN)
MUTE OFF
MS ON
70µs
G1
Pin voltage
Dolby C type NR
PBIN REVERSE
Dolby NR ON
MUTE ON
MS OFF
120µs
High
G2
CXA2561Q