TDA5201 Datasheet, PDF (28/43 Pages) Infineon Technologies AG – ASK Single Conversion Receiver

TDA 5201
Applications
4.5 Data Slicer Threshold Generation
The threshold of the data slicer especially for a coding scheme without DC-con-
tent, 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 Manches-
ter coding the threshold can be generated using an external R-C integrator as
shown in Figure 4-5. The time constant T_A of the R-C integrator has to be sig-
nificantly larger than the longest period of no signal change T_L within the data
sequence. 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
4-8
Specification, July 2004