AN4271 Datasheet, PDF (8/20 Pages) STMicroelectronics – Using the SPIRIT1 transceiver with range extender under EN 300 220 at 868 MHz

Transmitter parameters
AN4271
Figure 5. adjacent power measurement, 12.5 kHz narrow band channel spacing
Adjacent channel power, 2.4 kbps data rate, 2.4 kHz frequency deviaƟon
30
ACP = -30 dBm
20
10
0
-10
8.5 kHz
8.5 kHz
8.5 kHz
-20
-30
-40
-50
8.6948E+08
8.6949E+08
8.6950E+08
8.6951E+08
Frequency [Hz]
8.6952E+08
8.6953E+08
GAMS060320131441FSR
2.2
Modulation bandwidth
The range of the modulation bandwidth includes all associated side bands above the
appropriate emissions level and the frequency error or drift under extreme test conditions.
The frequency drift in extreme test conditions primarily depends on the crystal quality, which
is not included in this report.
This measurement applies to equipment not covered by the adjacent channel power clause,
so the measurement is performed for a case with a channel bandwidth greater than 25 kHz.
Figure 6 illustrates the ETSI spectral mask with which the radio must comply at the sub-
band edges. Basically, there are only two limit thresholds. What changes is the bandwidth of
integration at the different offset regions.
The same spectral mask is reported in Figure 7. The device center frequency is 869.5 MHz,
the data rate is set to 38.4 kbps, the frequency deviation to 20 kHz and Gaussian FSK
(GFSK) with a BT = 0.5 as modulation is chosen. The applied output power is set to 27
dBm.
With these parameters, the spectral masks of the SPIRIT1 complies with ETSI [2] sub-
clause 7.7.
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