Specifications

Measurements on CW Signals R&S FSH
1145.5973.12 2.4 E-10
Harmonic Measurements of a Sinewave Signal
Since a spectrum analyzer can resolve different signals in the frequency domain, it is ideal for
measuring harmonic levels or harmonic ratios. To speed up these operations, the R&S FSH has marker
functions that deliver fast results with only a few keystrokes.
As above, a signal generator with a 100 MHz output frequency and an output level of –20 dBm is used
in the following measurement example.
First, the R&S FSH is set to its default settings to show all measurement steps that are needed.
¾ Press the PRESET key.
The analyzer displays the frequency spectrum from 100 kHz to 3 GHz, the largest available span. At
100 MHz, the generator signal is displayed as a line. The generator harmonics are displayed as lines
at frequencies that are multiples of 100 MHz.
To measure the second harmonic ratio, set the start and stop frequency as follows:
¾ Press the FREQ key.
The softkey menu opens entering the frequency.
¾ Press the START softkey.
¾ Enter '50' using the numeric keypad and confirm the entry with the MHz key.
¾ Press the STOP softkey.
¾ Enter '250' using the numeric keypad and confirm the entry with the MHz key.
The R&S FSH now displays the spectrum from 50 MHz to 250 MHz and thus the signal at 100 MHz and
its second harmonic at 200 MHz.
To measure the harmonic ratio, set the marker on the fundamental and the delta marker on the second
harmonic.
¾ Press the MARKER key.
The softkey menu opens for marker entry and
automatically positions the main marker on the trace
maximum.
¾ Press the DELTA softkey.
The delta marker is activated (vertical dotted line) and
is automatically placed on the next trace maximum (=
second harmonic).
The harmonic ratio in dB can be read directly from the
numeric delta-marker display.