XE1203SKC868XE2 Semtech, XE1203SKC868XE2 Datasheet - Page 12

• Manufacturer Part Number: XE1203SKC868XE2
• Description: KIT STARTER FOR XE1203 868MHZ
• Manufacturer: Semtech
• Series: TrueRF™r
• Type: Transceiver, ISMr

Specifications of XE1203SKC868XE2

• Frequency: 868MHz
• For Use With/related Products: XE1203 (868MHz)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

4.1.8
When enabled this function provides an indication of the frequency error of the local oscillator compared with the
received carrier frequency. For guaranteed operation of the FEI function the following two conditions should be
met:
1) The modulation index, β, should meet the following condition:
where: Δf = frequency deviation of the modulated input signal, BR = input data bit-rate.
2) The bandwidth of the baseband filter (BBW) must be greater than the sum of the frequency offset and the
received peak signal bandwidth, as defined below:
BBW > f
where BBW is the baseband filter bandwidth defined by the RTParam_BW register. f
between the carrier frequency and the LO frequency, and BW
Note on the timing for FEI measurement: The timing diagram of the FEI measurement process is illustrated in
Figure 7 below. As long as the FEI function remains enabled, the frequency error is continuously measured every
2/BR seconds, starting TS_FEI (see Paragraph 3.2.2) after the FEI function is enabled. The measurement results
are loaded into the status registers Dataout_MSB_fei and Dataout_LSB_fei each time the Dataout_LSB_fei
register is read through the 3-wire serial interface. In the diagram below, Saout_fei is generated internally during a
read sequence from the “Dataout_LSB_fei ‘’ status register.
The maximum frequency of SCK during the FEI read operation is 100 kHz. When using the Konnex standard, the
bit ADParam_enable_konnex Configuration Register must be set to ‘1’.
© Semtech 2008
β
=
Dataout_MSB_fei&
2
BR
Dataout_LSB_fei
Δ ⋅
RTParam_FEI
Frequency Error Indicator – FEI
OFFSET
f
≥
saout_fei
, 2
EN
fei_out
+ BW
SIGNAL
Figure 7: Timing diagram of the FEI measurement process
first
evaluation
xxx
TS_FEI
val0
12
SIGNAL
val1
is equal to
val1
2/BR
val2
⎛
⎜
⎝
BR
2
+ f
Δ
⎞
⎟
⎠
val3
.
OFFSET
val3
XE1203F
is the difference
val4
www.semtech.com
0