cxa2561q Sony Electronics, cxa2561q Datasheet - Page 12

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

Description of Operation
1. Signal route
The CXA2561Q signal circuit is shown in Fig. 1.
2. Gain adjustment method
Adjust the playback equalizer amplifier gain so that –6dBm (Dolby level) is output on LINEOUT (Pins 7 and 24)
by playing back the reference tape for Dolby level adjustment.
Adjustment should be performed according to the rules of Dolby Laboratories Corporation because this IC has
the built-in Dolby NR system.
Dolby level is defined as 200nWb/m measured according to the ANSI high efficiency head method.
(dBm)
–10
–20
–30
–40
–50
–60
–70
–80
0
PBIN (HEAD)
PB IN
400Hz 200nWb/m: Dolby Level reference tape
FWD
RVS
PBOUT
Fig. 2. Level diagram
VR adjustment
PBFB
AMP1
PBTC
300k
Fig. 1. Signal route block diagram
TAPEIN
7k/12k
–30dBm
PBOUT
MUTE OFF
MUTE OFF
NR ON
LINEOUT
– 12 –
TAPEIN
(–30dBm)
–6dBm
(Dolby level)
NR OFF
100k
MUTE ON
MUTE ON
AMP2
VGS
VGS
24dB
24dB
Use the following reference tapes specified
by Dolby Laboratories Corporation.
1. A-bex Laboratories, Inc.
2. BASF (product code 09797 XE)
3. Kaneon Corp.
4. Standard Tape Laboratory
5. TEAC Corporation, Japan
6. TEAC Corporation of America
7. Victor Company of Japan, Ltd.
8. Sony Corporation (part no. TY-256)
LINEOUT
(–6dBm Dolby level)
(part no. TCC-130)
(LC Engineering part no. LCT-7001)
(catalogue no. 28)
(part no. MTT150)
(part no. MTT150)
(part no. TMT-6130, VTT-727)
NR
CXA2561Q