TDA7420 Datasheet, PDF (11/29 Pages) STMicroelectronics – MULTIFUNCTIONAUDIO PROCESSOR

Figure 1: Block Diagram of the Noise Blanker
TDA7420
MPX IN
VR
VSB
80KHz LP
1
I2C-BUS
SIGNAL PATH
LEFT
RIGHT
to INPUT SELECTOR
of AUDIOPROC.
AMP
BUF
RECT
AUTOMATIC
PEAK
THRESHOLD
CONTROL
BLANK COMP
PEAK COMP
REF.
+
-
ATC PEAK+VTH
40µs
CMOS OUTPUT
STAGE
TRIGGER
OUT
40µs
5
RECT-PEAK
4
ADDITIONAL THRESHOLD
CONTROL
(ATC-SB, MPX_RECT)
D94AU189A
RPEAK
82KΩ
CPEAK
47nF
CBLANK
330pF
Figure 2: Trigger Threshold vs. Vpeak
VTH
8 STEPS
TRIG. THRESHOLD
65mV
30mV
0.9V
D94AU186B
280mV
240mV
180mV
140mV
NOISE ADJUSTED
TRIG. THRESHOLD
1.4V
VPEAK(V)
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