TDA5204E1 Datasheet, PDF (26/40 Pages) Infineon Technologies AG – ASK Single Conversion Receiver 390MHz

TDA 5204 E1
preliminary
Applications
4.5 Data Slicer Threshold Generation
The threshold of the data slicer can be generated in two ways, depending on
the signal coding scheme used. In case of a signal coding scheme without DC
content such as Manchester coding the threshold can be generated using an
external R-C integrator as shown in the following . The cut-off frequency of the
R-C integrator has to be lower than the lowest frequency appearing in the data
signal. In order to keep distortion low, the minimum value for R is 20kΩ.
R
C
Pins: 19
data
filter
20
U_threshold
data out
25
data slicer
Figure 4-5
Data_slice1.wmf
Data Slicer Threshold Generation with External R-C Integrator
Another possibility for threshold generation is to use the peak detector in con-
nection with two resistors and one capacitor as shown in the following figure.
The component values are depending on the coding scheme and the protocol
used.
R
C
R
Pins: ₂₆ 19
peak detector
20
U_threshold
data out
25
data slicer
data
filter
Figure 4-6
Data_slice2.wmf
Data Slicer Threshold Generation Utilising the Peak Detector
Wireless Components
4-7
Specification, January 2001