xe1202 ETC-unknow, xe1202 Datasheet - Page 9

• Manufacturer Part Number: xe1202
• Description: Low-power, Integrated Uhf Transceiver
• Manufacturer: ETC-unknow

For applications where the time needed to get the first right result from the RSSI has to be as low as possible, this
time can be minimized by waking up the RSSI during mode 010 instead of 100 which is the condition for the
definition of TS_RS in page 6 (for definition of modes, see pages 19 and 20).
4.1.4
When activated, this function provides information about the frequency error of the local oscillator compared with
the input carrier frequency. The condition on the modulation index for proper behavior of the FEI function is:
where f is the frequency deviation and BR is the bit rate.
There are 2 modes of operation for this function selected by the bit “RTParam_Fsel” (see the Configuration register
section below).
IMPORTANT NOTE
To guarantee proper behavior of the FEI, the sum of frequency offset and the signal bandwidth (ssb) should be
lower than the baseband filter bandwidth (single sided). That is
where f
(single sided) equal to the sum of the bitrate divided by 2 and the frequency deviation (Bitrate/2 + Frequency
Deviation), and Baseband_filterBW is the channel filter bandwidth defined by the RTParam_BW parameter (see the
Configuration Registers section below).
4.1.4.1
To activate the FEI function, the bit “RTParam_FEI” must be set to “1”. When activated, the function provides a 2-
bits status stored in register “DataOut_FEI”. The meaning of this output is given in the following table, where f
the internal local oscillator frequency, and f
9
offset
Frequency Error Indicator - FEI
“RTParam_Fsel” = 1
is the difference between the carrier frequency and the LO frequency, SignalBW is the signal bandwidth
2
BR
f
RTParam_RSSI
RTParam_RSSI
DataOut_RSSI
DataOut_RSSI
, 2
rssi_out
rssi_out
datain
datain
Figure 1 RSSI measurement timing diagram
en
en
DataOut_FEI
0 0
0 1
1 0
1 1
f
offset
RF
+ SignalBW < Baseband_filterBW
Table 2 FEI status description
is the carrier frequency of the received signal.
TS_RS
TS_RS
XX
XX
XX
XX
VAL1
VAL1
(f
(f
f
LO
LO
LO
VAL2
VAL2
Meaning
-f
-f
-f
RF
RF
RF
) < -f
-
) > f
VAL3
VAL3
f
ERR
ERR
ERR
VAL2
VAL2
VAL4
VAL4
VAL4
VAL4
Data Sheet
XE1202
XX
XX
D0211-105
LO
is