Fast Level Measurement Using Frequency Lists - Rohde & Schwarz R&S FSP Series Operating Manual

R&S FSP
7.3.7

Fast Level Measurement Using Frequency Lists

A typical task for the R&S FSP is power measurement at a number of frequency
points, e.g. at multiples of the fundamental (harmonics measurement), or at frequen-
cies defined by a mobile radio standard (e.g. spectrum due to transients at
± 200 kHz, ± 400 kHz, etc. about the carrier frequency of a GSM signal). In many
cases, different level and/or bandwidth settings are required for the different fre-
quency points to match the channel spacing and meet the requirements of dynamic
range.
Especially for this application, the R&S FSP offers a number of remote-control func-
tions (commands available in SENSe:LIST subsystem) that allow level measure-
ment based on a frequency list with different instrument settings assigned to
different frequencies. Not only the frequency list can be programmed, but also the
measurement types (PEAK, RMS, AVG) to be performed simultaneously can be
selected.
The example below describes a harmonics measurement on a dual-band amplifier.
The harmonics level in general decreases as the frequency increases. To boost
measurement sensitivity, therefore, the reference level is lowered by 10 dB from the
third harmonic.
The following settings are used:
• Reference level: 10.00 dBm up to 2nd harmonic, 0 dBm from 3rd harmonic
• RF attenuation: 20 dB
• Electronic attenuation: 0 dB
• RBW: 1 MHz
• VBW: 3 MHz
• Filter type: NORMal
Measurement time: 300 µs
•
Trigger delay: 100 µs
•
• Trigger: video, 45%
Frequency
935.2 MHz
1805.2 MHz
1870.4 MHz
2805.6 MHz
3610.4 MHz
3740.8 MHz
5815.6 MHz
The frequencies are selected in ascending order to minimize system-inherent wait-
ing times resulting from frequency changes.
At each frequency point the peak power and the rms power are measured. The peak
power and the rms power values are stored alternately in the results memory.
7.22
Type
GSM 900 fundamental
GSM 1800 fundamental
GSM 900 2nd harmonic
GSM 900 3rd harmonic
GSM 1800 2nd harmonic
GSM 900 4th harmonic
GSM 1800 3rd Harmonic
Remote Control – Programming Examples
More Complex Programming Examples
Operating Manual 1164.4556.12 - 06