HA12226F Datasheet, PDF (13/84 Pages) Hitachi Semiconductor – Audio Signal Processor for Cassette Deck(Dolby B-type NR with Recording System)

HA12226F/HA12227F
Time constant of detection
Figure 6(1) generally shows that detection time is in proportion to value of capacitor C13. But, with Attack*¹ and
Recovery*² the detection time differs exceptionally.
Notes: 1. Attack : Non-music to Music
2. Recovery : Music to Non-music
Recovery
Attack
Recovery
Attack
Recovery
Attack
C13
R13
Detection level _{Input level}
(1)
(2)
(3)
Figure 6 Function Characteristic of MS
Like the figure 6(2), Recovery time is variably possible by value of resistor R13. But Attack time gets about fixed
value. Attack time has dependence by input level. When a large signal is inputted, Attack time is short tendency.
Music Sensor Output (MSOUT)
As for internal circuit of music sensor block, music sensor output pin is connected to the collector of NPN type
directly, output level will be “high” when sensing no signal. And output level will be “low” when sensing signal.
Connection with microcomputer, it is requested to use external pull up resistor (R_L = 10 kΩ to 22 kΩ)
Note: Supply voltage of MSOUT pin must be less than V_CC voltage.
The Tolerances of External Components for Dolby NR-Block (Only the HA12226F)
For Dolby NR precision securing, please use external components shown at figure 7. If leak-current are a few
electrolytic-capacitor, it can be applicable to C5 and C23.
C23
0.1µ
±10%
42
DET (L)
HA12226F
DET (R)
1
C5
0.1µ
±10%
BIAS1
2
R5
33k
±2%
Figure 7 Tolerance of External Components
Rev.6.00 Jun 15, 2005 page 13 of 83