Specifications
ETSI
Final draft ETSI EN 300 328 V1.8.1 (2012
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04)
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5.3.4.2 Test method
5.3.4.2.1 Conducted measurements
The test procedure shall be as follows:
Step 1:
• The output of the transmitter shall be connected to a spectrum analyzer or equivalent.
• The analyzer shall be set as follows:
- Centre Frequency: Equal to the hopping frequency being investigated
- Frequency Span: 0 Hz
- RBW: ~ 50 % of the Occupied Channel Bandwidth
- VBW:
RBW
- Detector Mode: RMS
- Sweep time: Equal to the Dwell Time × Minimum number of hopping frequencies (N)
(see clause 4.3.1.3.2)
- Number of sweep points: 30 000
- Trace mode: Clear / Write
- Trigger: Free Run
Step 2:
• Save the trace data to a file for further analysis by a computing device using an appropriate software
application or program.
Step 3:
• Indentify the data points related to the frequency being investigated by applying a threshold.
The data points resulting from transmissions on the hopping frequency being investigated are assumed to have
much higher levels compared to data points resulting from transmissions on adjacent hopping frequencies. If a
clear determination between these transmissions is not possible, the RBW in step 1 shall be further reduced. In
addition, a channel filter may be used.
• Count the number of data points identified as resulting from transmissions on the frequency being investigated
and multiply this number by the time difference between two consecutive data points.
Step 4:
• The result in step 3 is the accumulated Dwell Time which shall comply with the limit provided in
clauses 4.3.1.3.2.1 or 4.3.1.3.2.2 and which shall be recorded in the test report.
Step 5:
• Make the following changes on the analyzer and repeat steps 2 and 3.
Sweep time: 4 × Dwell Time × Actual number of hopping frequencies in use
The hopping frequencies occupied by the system without having transmissions during the dwell time
(blacklisted frequencies) should be taken into account in the actual number of hopping frequencies in use. If
this number can not be determined (number of blacklisted frequencies unknown) it shall be assumed that the
equipment uses the minimum number of hopping frequencies as defined in clauses 4.3.1.4.2.1 or 4.3.1.4.2.2.
• The result shall be compared to the limit for the Minimum Frequency Occupation Time defined in
clauses 4.3.1.3.2.1 or 4.3.1.3.2.2. This value shall be recorded in the test report.