TDA7200 Datasheet, PDF (24/49 Pages) Infineon Technologies AG – ASK/FSK Single Conversion Receiver

T_A has to be calculated as
T_A
=
R1⋅ (R_{F 3int}
R1 + R_{F 3int}
+ R_{F 4int} )
+ R_{F 4int}
⋅
C13
and
T_A
=
R1⋅ R_{F 4int}
R1+ R_{F 3int} + R_{F 4int}
⋅ C13
= R1II (R_{F 3int} + R_{F 4int} ) ⋅ C13
= ^{R1II (RF 3int + RF 4int )} ⋅ C13
v
R1, R_{F3 int}, R_{F4 int} and C13 see also Figure 7 and Figure 9
TDA7200
Applications
... for ASK
... for FSK
19
20 U_threshold
25
Figure 7
data
CM
filter
data slicer
Data Slicer Threshold Generation with External R-C Integrator
In case of ASK operation another possibility for threshold generation is to use the peak
detector in connection with an internal resistive divider and one capacitor as shown in
Figure 8. For selecting the peak detector as reference for the slicing level a logic low as
to be applied on the SSEL pin.
In case of MSEL is high (or open), which means that ASK-Mode is selected, a logic low
on the SSEL pin yields a logic high on the AND-output and thus the peak-detector is
selected (see Figure 9).
In case of FSK the MSEL-pin and furthermore the one input of the AND-gate is low, so
the peak detector can not be selected.
The capacitor value is depending on the coding scheme and the protocol used.
Data Sheet
24
V 1.0, 2007-05-02