TDA7705_10 Datasheet, PDF (33/42 Pages) STMicroelectronics – Highly integrated tuner for AM/FM car radio

TDA7705
5
Weak signal processing
Weak signal processing
All the parameters in this section refer to the programmability of the DSP part of the device.
The typical values are those set by default parameters (start-up without parametric change
from main µP); the max and the min values refer to the programmability range. The values
are referred to the typical application (Figure 16: Example of FM tuned (narrow-band)
application / SPI control). Wherever the possible values are a discrete set, all the possible
programmable values are displayed.
5.1
FM IF-processing
5.1.1 Dynamic channel selection filter (DISS)
Table 26. Dynamic channel selection filter (DISS)
(discrete set)
Symbol
Parameter
Test condition
IF filter #6
IF filter #5
IF filter #4
DISS BW IF filter #3
response: - 3dB
IF filter #2
IF filter #1
IF filter #0
Min
Typ
Max Units
-
±150
-
kHz
-
±110
-
kHz
-
±80
-
kHz
-
±60
-
kHz
-
±45
-
kHz
-
±35
-
kHz
-
±25
-
kHz
5.1.2 Soft mute
Table 27.
Symbol
Soft mute
(continuous set)
Parameter
Test condition
Min
audio atten = 1 dB
SMsp Start point vs. field strength read “FM_softmute”
0
no adjacent channel present
audio atten = SMd + 1 dB
SMep End point vs. field strength read “FM_softmute”
-6
no adjacent channel present
SMd Depth
-
-30
Field strength LPF cut-off
SMtauatt frequency for soft mute
-
0.1
activation
Field strength LPF cut-off
SMtaurel frequency for soft mute
-
0.1
release
Typ Max Units
6
20 dBµV
-6
10 dBµV
-15
0
dB
100 4000 Hz
1
4000 Hz
Doc ID 15938 Rev 8
33/42