Transmitter parameter

AN4126

18/28

Doc ID 023299 Rev 1

Figure 12.

6 dB bandwidth measurement

3.2.2

Digital modulation schemes peak output power

To measure the peak output power, center the spectrum analyzer on the required channel

and put the SPIRIT1 into modulated mode. Set the span about 5 times the 6 dB bandwidth

measurement, the RBW greater than the 6 dB bandwidth and the VBW equal to or greater

than the RBW. The maximum permitted peak conducted output power is 30 dBm (1 W). The

SPIRIT1 output power is lower than the maximum permitted output power. An external PA

can be used to reach the maximum output power.

To perform this measurement on the SPIRIT1, the cases with 2-FSK modulation, 500 kbps

data rate and 250 kHz frequency deviation are chosen. The span is set to 2 MHz (3 times

the 6 dB measured bandwidth), the RBW is set to 1 MHz (greater than the 6 dB bandwidth),

and the VBW equal to the RBW. The measured SPIRIT1 output power is 10 dBm. This

output power is lower than the maximum permitted output power. An external PA must be

used to reach the maximum output power.

AM13156v1

-50

-40

-30

-20

-10

0

10

20

9.131E+08

9.136E+08

9.141E+08

9.146E+08

9.151E+08

9.156E+08

9.161E+08

9.166E+08

9.171E+08

Frequency [Hz]

2-FSK, 500 kbps 250 kHz

6 dB bandwidth

6 dB bandwidth