14.4.3.3 Spectrum Mask

The AT86RF212B can be operated in different frequency bands, using different power levels, modulation schemes, chip rates, and pulse shaping filters. The occupied bandwidth of the transmit signal depends on the chosen mode of operation. Values listed in table below are based on a default power setting of +5dBm and usage of the Continuous Transmission Test Mode with Frame Buffer content {0x01, 0x00}.

Knowledge of modulation bandwidth, power spectrum, and side lobes is essential for proper system setup that produces non-overlapping channel spacing.

Table 14-32. Physical Layer Mode and Occupied Bandwidth
PHY Mode

99% Occupied

Bandwidth [kHz]

6dB

Bandwidth [kHz]

20dB

Bandwidth [kHz]

Reference

Detector

Span

RBW

VBW

Sweep

ETSI EN 300 220 [6]

RMS

2 MHz

100 kHz

1 MHz

500 ms

FCC 15.247 [5]

Peak/MaxHold

2 MHz

5 % of bandwidth

3 x RBW

AUTO

FCC 15.247 [5]

Peak/MaxHold

2 MHz

1% of bandwidth

3 x RBW

AUTO
BPSK-20 445 295 430
BPSK-40 775 570 850
BPSK-40-ALT 805 620 815
OQPSK-SIN-RC-100 450 260 340
OQPSK -RC-100 490 355 365
OQPSK-SIN-250 1190 645 1210
OQPSK-RC-250 1245 850 1220

The following figures show the power spectra for the different modes listed in the table above. The spectra were captured using default settings of AT86RF212B. The resolution bandwidth of the spectrum analyzer was set to 30kHz; the video bandwidth was set to 10kHz. For the OQPSK-SIN-250 modulation and OQPSK-RC-250 modulation the resolution bandwidth of the spectrum analyzer was set to 100kHz; the video bandwidth was set to 30kHz.

Figure 14-40. Spectrum of BPSK-20
Figure 14-41. Spectrum of BPSK-40
Figure 14-42. Spectrum of BPSK-40-ALT
Figure 14-43. Spectrum of OQPSK-SIN-RC-100
Figure 14-44. Spectrum of OQPSK-RC-100
Figure 14-45. Spectrum of OQPSK-SIN-250
Figure 14-46.  Spectrum of OQPSK-RC-250

The figures above illustrate typical spectra of the transmitted signals of the AT86RF212B and do not claim any limits.

Refer to the local authority bodies (FCC, ETSI, etc.) for further details about definition of power spectral density masks, definition of spurious emission, allowed modulation bandwidth, transmit power, and its limits.