T5761 ATMEL [ATMEL Corporation], T5761 Datasheet - Page 11

• Manufacturer Part Number: T5761
• Description: UHF ASK/FSK Receiver
• Manufacturer: ATMEL [ATMEL Corporation]

Digital Signal Processing
The data from the ASK/ FSK demodulator (Dem_out) is
digitally processed in different ways and as a result con-
verted into the output signal data. This processing
depends on the selected baud-rate range (BR_Range).
Figure 14 illustrates how Dem_out is synchronized by the
extended clock cycle T
bit-check counter. Data can change its state only after
T
Data signal as a result is always an integral multiple of
T
The minimum time period between two edges of the data
Rev. A2, 19-Oct-00
Dem_out
Data_out (DATA)
IC_ACTIVE
Bit check
Data_out (DATA)
Dem_out
Clock bit–check
counter
XClk
XClk
Dem_out
Data_out (DATA)
.
has elapsed. The edge-to-edge time period t
Start–up mode
XClk
t
T
DATA_min
Figure 16. Steady L state limited DATA output pattern after transmission
XClk
. This clock is also used for the
Figure 14. Synchronization of the demodulator output
t
Figure 15. Debouncing of the demodulator output
ee
Preliminary Information
Bit–check mode
ee
t
ee
of the
t
DATA_min
signal is limited to t
cient suppression of spikes at the DATA output. At the
same time it limits the maximum frequency of edges at
DATA. This eases the interrupt handling of a connected
The maximum time period for DATA to stay Low is lim-
ited to T
a finite response time in programming or switching off the
receiver via Pin DATA. T
than the maximum time period indicated by the transmit-
ter data stream. Figure 16 gives an example where
Dem_out remains Low after the receiver has switched to
receiving mode.
C.
Receiving mode
DATA_L_max
t
ee
T5760 /
t
ee
. This function is employed to ensure
DATA_min
T
DATA_min
DATA_L_max
t
DATA_min
. This implies an effi-
t
DATA_L_max
is thereby longer
T5761
t
ee
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