CXA2561Q
Description of Operation
1. Signal route
The CXA2561Q signal circuit is shown in Fig. 1.
24dB
24dB
NR OFF
NR ON
PB IN
MUTE ON
MUTE OFF
FWD
AMP1
300k
7k/12k
RVS
AMP2
NR
MUTE OFF
MUTE ON
VGS
100k
VGS
PBFB
PBTC
PBOUT
TAPEIN
(–30dBm)
LINEOUT
(–6dBm Dolby level)
Fig. 1. Signal route block diagram
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.
Use the following reference tapes specified
0
by Dolby Laboratories Corporation.
–6dBm
–10
–20
–30
–40
–50
–60
–70
(Dolby level)
1. A-bex Laboratories, Inc.
(part no. TCC-130)
PBOUT
LINEOUT
2. BASF (product code 09797 XE)
3. Kaneon Corp.
–30dBm
VR adjustment
(LC Engineering part no. LCT-7001)
4. Standard Tape Laboratory
(catalogue no. 28)
TAPEIN
5. TEAC Corporation, Japan
(part no. MTT150)
400Hz 200nWb/m: Dolby Level reference tape
–80
6. TEAC Corporation of America
(part no. MTT150)
PBIN (HEAD)
(dBm)
7. Victor Company of Japan, Ltd.
(part no. TMT-6130, VTT-727)
8. Sony Corporation (part no. TY-256)
Fig. 2. Level diagram
– 12 –
SONY [ SONY CORPORATION ]
