Transmitter parameter

AN4126

22/28

Doc ID 023299 Rev 1

3.2.5

Spurious RF conducted emission

According to FCC part 15.247, all the other emissions outside these bands must not exceed

the general radiated emission limits specified in part 15.209. According to part 15.33, for an

intentional radiator operating below 10 GHz, the frequency range of measurements must be

until the tenth harmonic of the highest fundamental or to 40 GHz, whichever is lower. The

SPIRIT1’s highest fundamental frequency is 928 MHz, so the tenth harmonic is 9.28 GHz

which is the frequency range of measurement. In

Figure 17 and 18 the spurious conducted

emissions and the FCC emission mask are shown. The carrier is modulated with a 2-FSK

modulation with a data rate of 500 kbps and a frequency deviation of 250 kHz. The SPIRIT1

fully complies with the conducted spurious emission requirements.

Figure 17.

Spurious conducted emission below 1 GHz measurement

AM13161v1

-70

-60

-50

-40

-30

-20

-10

0

10

20

1.000E+07

1.100E+08

2.100E+083.100E+08

4.100E+08

5.100E+08

6.100E+08

7.100E+088.100E+08

9.100E+08

Frequency [Hz]

2-FSK, 500 kbps, 250 kHz