AN4110

Transmitter parameter

Doc ID 023182 Rev 1

7/18

Figure 4.

Adjacent power measurement, 25 kHz narrowband channel spacing,

9.6 kbps data rate, 2.4 kHz frequency deviation

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.

Figure 5 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 masks are reported in Figure 6 and 7 as well. The device center

frequency is 868.3 MHz, the data rate is set to 9.6 kbps, the frequency deviation is set to 2.4

kHz, and the modulation is set to gaussian FSK (GFSK) with a BT = 1, in Figure 6, 38.4

kbps as data rate, 20 kHz as frequency deviation and gaussian FSK (GFSK) with a BT = 1

as modulation, in Figure 7. The applied output power is set to 11 dBm. With these

parameters, the spectral masks of the SPIRIT1 comply with ETSI [2] subclause 7.7.