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Select [Span]
Use number keys,knob or up/down arrow key to set span to 5MHz
By now the signal is show in the screen as shown in figure 4-1.
6) User a marker to measure the frequency and amplitude of the signal
Press
【
Marker
】
key
→
[Marker]
→
1
，
activate Marker1.
Press
【
Peak
】
key, the marker will be moved to signal peak automatically. Marker information will be shown in
up-right corner.
7) Readout the test result
Fig 4-1: Continuous signal Test result
4.3.
Measure two signals with small frequency interval
Signal resolution is determined by the resolution bandwidth (RBW). When a signal passes through the filter, the spectrum analyzer will
use the signal to sweep and display the band pass shape of the IF filter. So, when the spectrum analyzer receives two signals with equal
amplitude and close frequency interval, the top of one band-pass filter waveform nearly covers another one, making two signals like one.
If two signals of different amplitudes but close frequency interval, small signals may be totally hidden by large signals.
4.3.1.
Resolving Two Signals of Equal Amplitude
Generally, to resolve two signals of equal amplitude, the resolution bandwidth must be less than or equal to the frequency interval of the
two signals. For example, to resolve two signals of equal amplitude and a frequency interval of 100 kHz, the resolution bandwidth of the
spectrum analyzer should be set less than or equal to 100 kHz.
Example
Take measuring two signals of equal amplitude with a frequency interval of 100kHz as an example, the measurement steps are as
follows:
1) Connect the outputs of two signal generators to the spectrum analyzer RF input port using a T-shaped connector, as shown in
