ICs for Cassette, Cassette Deck
s
Effect of dbxII Noise Reduction System
(Without noise reduction system)
+20dB
Fortissimo
+10dB
0dB
Magnetron tape
Input Level
60 ~ 70dB
Recording
Playback
Magnetron saturation level Distortes
+10dB
DC range
Output
AN6291, AN6291S
Fortissimo (large sound)
distortes due to magnetron
saturation
Even if input width is
100dB, width 60-70dB is
playbacked in output.
Z-
100dB
– 60dB
– 60dB
Pianissimo
– 80dB
Noise level
Noise
Pianissimo (small sound)
is erased by the hysnoise
of tape
(When dbx
II
System is ON)
+20dB
Fortis
Recording (Encode)
0dB
100dB
Input level
Decre
simo
ase
+10dB
Magnetron tape
Increase
o
Fortissim
Playback
(Decode)
+20dB
Large sound is playbacked
without distortion
Compressed to
1/2 by dB
Expanded to
2 times by dB
D range
Output
100dB of input range
is playbacked as well
– 40dB
Pian
issim
Dec
o
reas
e–
80d
Noi
B
se l
eve
l
mo
ssi
se
ani
Pi
rea
Inc
– 80dB
Small sound is playbacked, too.
Noise level is decreased more
than by 30dB at the playback
mode (Improvement of S/N
ratio)
Noise
Fortissimo is decreased less
than saturation level and
pianissimo is increased
more than noise level. Thus
they are recorded.
D range is expanded in equal
value as fortissimo is
increased and pianissimo is
decreased its level, and they
are playbacked.
s
Cautions
(1) When users use the AN6291 and the AN6291S, contract should be made between the dbx Technology Licensing. dbx
licence and trademark should be contacted with the following.
the U.S.A. : dbx Technology Licensing
JAPAN Office : dbx Technology Licensing
433 California Street, Third Floor
San Francisco, California 94104
Tel : 415-765-2801
Tel : 03-3378-0915
Fax : 03-3374-5191
Fax : 415-765-2141
(2) Capacitor between the Pin6 – 7 and Pin16 –17 is used to cut DC current.
When leakage of DC current is large, encode and decode characteristics is not right value, capacitor's leakage should be as
minimum as possible.
(3) The AN6291 is a low power consumption current type. So effection of wiring resistance is small and oscillation character-ist
of pattern location is good, however, when impedance of the input pin is high, wiring should be shorter because it is easily
effected by external noises.
PANASONIC [ PANASONIC SEMICONDUCTOR ]
