Safety Information

Page 30 of 33 Report No.:FCS202103006W01
Flux Compliance Service Laboratory
Room 105 Floor Bao hao Technology Building 1 NO.15 Gong ye West Road Hi-Tech Industrial, Song shan lake Dongguan
Tel: [phone] Fax:[phone] http://www.fcs-lab.com
6. 20 DB BANDWIDTH TEST
6.1 LIMIT
According to 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. The requirement to contain the designated bandwidth of the emission
within the specified frequency band includes the effects from frequency sweeping, frequency
hopping and other modulation techniques that may be employed as well as the frequency
stability of the transmitter over expected variations in temperature and supply voltage. If a
frequency stability is not specified in the regulations, it is recommended that the fundamental
emission be kept within at least the central 80% of the permitted band in order to minimize the
possibility of out-of-band operation
6.2 TEST PROCEDURE
a.
Check the calibration of the measuring instrument using either an internal calibrator or a
known signal from an external generator
b.
Position the EUT 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. Set a reference level on the measuring instrument equal to the highest
peak value.
c.
Measure the frequency difference of two frequencies that were attenuated 20 dB from the
reference level. Record the frequency difference as the emission bandwidth.
6.3 TEST SETUP