HA12209F データシートの表示（PDF） - Hitachi -> Renesas Electronics

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HA12209F

Audio Signal Processor for Cassette Deck (Dolby B-type NR with Recording System)

Hitachi -> Renesas Electronics 

The sensitivity of Music Sensor

Gv

HA12209F

f1 =

1

[Hz]

2π · C26 · 100k

f2 = 25k [Hz]

f

f1

f2

Figure 5 Frequency Characteristic of MSIN

Occasion of the external component of figure 4, f1 is 159Hz. A standard level of MS input pin

25.9mVrms, therefore, the sensitivity of music sensor (S) can request it, by lower formulas.

A = MS Amp Gain

B = PB input Gain × (1/2)*1

C = Sensed voltage

S = 20log

C

[dB]

25.9 · A · B

20log (A × B) = D [dB]

PB input Gain = 21.3 [dB]

S = 14 – D [dB]

Note: 1. Case of one-sided channel input.

Time Constant of Detection

Figure 6(1) generally shows that detection time is in proportion to value of capacitor C10. But, with

Attack*2 and Recovery*3 the detection time differs exceptionally.

Recovery

Attack

Recovery

Attack

Recovery

Attack

C10

Function Characteristic of MS (1)

R12

Detection level

Input level

Function Characteristic of MS (2) Function Characteristic of MS (3)

Figure 6 Function Characteristics of MS

Like the figure 6(2), Recovery time is variably possible by value of resistor R12. 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.

Note: 2. Attack : Non-music → Music

3. Recovery : Music → Non-music

Rev.2, Jun. 1999, page 11 of 49

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