ETC Report No. : 16-09-RBF-027
Sheet 32
of 36 Sheets
FCC ID:
2AC96WDP
32
9. BANDWIDTH OF EMISSION
9.1 Applicable Standard
Per FCC rule §15.215(c), intentional radiators operating under the alternative provisions to
the general emission limits, as contained in §§15.217 through 15.257 and in subpart E of
this part, must be designed to ensure that the 20 dB bandwidth of the emission, or
whatever bandwidth may otherwise be specified in the specific rule section under which
the equipment operates, is contained within the frequency band designated in the rule
section under which the equipment is operated.
9.2 Measurement Procedure
1. Check the calibration of the measuring instrument using either an internal calibrator or a
known signal from an external generator.
2. Position the EUT as shown in figure 4 without connection to measurement instrument.
Turn on the EUT and connect it to measurement instrument. Then set it to any one
convenient frequency within its operating range. The settings of spectrum analyzer is as
followings.
1) Set RBW in the range of 1% to 5% of the OBW.
2) Set the video bandwidth (VBW) ≥ 3 x RBW.
3) Detector = Peak.
4) Trace mode = max hold.
5) Sweep = auto couple.
6) Allow the trace to stabilize.
7) Measure the maximum width of the emission that is constrained by the frequencies
associated with the two outermost amplitude points (upper and lower frequencies)
that are attenuated by 20 dB relative to the maximum level measured in the
fundamental emission. Alternatively, use the -20 dB bandwidth function of the
spectrum analyzer.
3. Repeat above procedures until all frequencies measured were complete.
Figure 4: Emission bandwidth measurement configuration.
EUT
Test Receiver
