TDA5250D2 Datasheet, PDF (74/97 Pages) Infineon Technologies AG – ASK/FSK 868MHz Wireless Transceiver

confidential
TDA 5250 D2
preliminary
Applications
Example to calculate the thresholds for a given data rate:
- Data signal manchester coded
- Data Rate: 2kbit/s
- f_clk= 18,0896 MHz
Then the period equals to
2⋅T
=
1
2kbit/s
= 0,5ms
[4 – 36]
respectively the high time is 0,25ms.
We set the thresholds to +-10% and get: T1= 0,225ms and T2= 0,275ms
The thresholds TH1 and TH2 are calculated with following formulas:
TH1
=
T1⋅
f_clk
4
TH2
=
T2
⋅
f _clk
4
[4 – 37]
[4 – 38]
This yields the following results:
TH1~ 1017= 001111111001_b
TH2~ 1243= 010011011011_b
which have to be programmed into the D0 to D11 bits of the COUNT_TH1 and
COUNT_TH2 registers (subaddresses 06H and 07H), respectively.
Default values (window counter inactive):
TH1= 000000000000_b
TH2= 000000000001_b
Note: The timing window of +-10% of a given high time T in general does not
correspond to a frequency window +-10% of the calculated data frequency.
Wireless Components
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Specification, July 2002