XE1202AI027TRLF Semtech, XE1202AI027TRLF Datasheet - Page 14

• Manufacturer Part Number: XE1202AI027TRLF
• Description: Narrow Band 433/868/915MHz RF Transceiver
• Manufacturer: Semtech

The characteristic of the smoothing filter is the ratio t
“RTParam_Stair”, as illustrated in Table 9:
4.1.6
XE1202A TrueRF™ includes a pattern recognition function. When “ADParam_Pattern” (see the Configuration
register section below) is set to “1” pattern recognition is enabled, providing that the bit synchronizer is also
enabled. With the pattern recognition function enabled, the demodulated data is compared with a pattern stored in
the “Pattern” register. The length of this pattern can be 8, 16, 24, or 32 bits, as defined by “ADParam_Psize”. When
comparing the streams 0, 1, 2, or 3 errors, as defined by “ADParam_Psize” can be allowed to detect a match. The
PATTERN output is driven by the output of this comparator. It is “high” when a match is detected, otherwise “low”.
When the feature is disabled, the PATTERN output is set to “low”.
4.1.7
The exact frequency step of the frequency synthesizer can be obtained from the following equation:
As an example, if FXTAL is exactly 39 MHz, FSTEP = 501.13 Hz.
© Semtech 2006
IN freq_synth
IN freq_synth
datain
FSTEP = FXTAL / 77 824.
no filtering
staircase filtering
Pattern recognition
Frequency synthesizer
t
bit
Figure 6: Modulation without and with pre-filtering
FSParam_Stair
0
1
Table 9: Smoothing filter
rise
15
/t
bit
. The value of this ratio is programmable with the register
t
10 %
20 %
rise
t
rise
/t
bit
XE1202A TrueRF™
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