LA1781M_09 Datasheet, PDF (30/48 Pages) Sanyo Semicon Device – For Car Radios Single-Chip Tuner IC

10
0
--10
--20
--30
--40
--50
--60
--70
--20
LA1781M
FM Soft Muting (2)
Fig. 21
R47 = 7.5kΩ
DET out
10kΩ
15kΩ
58
200kΩ
20kΩ
Noise
--10
0
10
20
30
40
Antenna input -- dBμ
10
0
--10
--20
--30
--40
--50
--60
--70
--20
FM Soft Muting (3)
Fig. 22
R47 = 7.5kΩ
DET out
10kΩ
15kΩ
58
30kΩ
20kΩ
Noise
--10
0
10
20
30
40
Antenna input -- dBμ
VCC
200kΩ
R
+
--
Quadrature detector
Mute amp.
(VCA)
N-AGC
R
+
--
R
Mute
drive
Limiter
58
33
To MIX out
Open
200kΩ
30kΩ
Fig. 23
• FM muting off function
Forcing this pin to the ground level turns muting off.
Detecter
output ⁰
1
20
When the pin is at the ground level, the noise convergence will
be 10dB and the -3dB limiting sensitivity will be about 0dBμ.
Fig. 24
Antenna input
31
DET out
No.6038-30/48