Rohde & Schwarz FSQ series, Quick Start Manual

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R&S FSQ Basic Measurement Examples
Measuring Harmonics of Sinusoidal Signals
5.8 Quick Start Guide 1313.9652.62 - 02
5.2 Measuring Harmonics of Sinusoidal Signals
Measuring the harmonics of a signal is a very common task that can be optimally performed
by using an analyzer.
In the following example, the generator signal with 128 MHz and -30 dBm is used again.
5.2.1 Measuring the Suppression of the First and Second Harmonic of an
Input Signal
1. Reset the instrument.
➢
Press the PRESET key.
The R&S FSQ is now in the default state.
2. Set the start frequency to 100 MHz and the stop frequency to 400 MHz.
➢
Press the FREQ key.
➢
Press the START softkey and enter 100 MHz .
➢
Press the STOP softkey and enter 400 MHz .
The R&S FSQ displays the fundamental and the first and second harmonics of the input
signal.
3. For maximum sensitivity, set the RF attenuation to 0 dB.
➢
Press the AMPT key.
➢
Press the RF ATTEN MANUAL softkey and enter 0 dB .
4. To average (suppress) the noise, reduce the video bandwidth.
➢
Press the BW key.
➢
Press the COUPLING RATIO softkey.
➢
Using the arrow keys, select RBW/VBW NOISE [10] .
The video bandwidth (VBW) will now always be set to less than the resolution bandwidth
(RBW) by a factor of 10.
5. Activate the marker.
➢
Press the MKR key.
Marker 1 will be activated and positioned to the signal maximum (fundamental at 128
MHz). The level and frequency of the marker will be displayed in the marker information
field.
6. Activate the delta marker and measure the harmonic suppression.
➢
Press the MARKER 2 softkey in the marker menu.
Marker 2 will be activated as the delta marker (Delta 2 [T1]). It automatically appears on
the largest harmonic of the signal. The frequency offset and level offset from marker 1
are displayed in the marker field at the top edge of the screen.