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- Press [Max.value search], marker is at peak frequency;
marker makes marks at signal peak, and marker's frequency
and amplitude will be displayed in the upper right of screen.
3. Read measurement results
Measured frequency of input signal is 300MHz, amplitude
is -9.44dBm, as shown in Figure 4-1:
Figure 4-1 Measurement Result of Sinusoidal Signal
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4.2 Measurement of Signals with Close
Resolution Bandwidth and Resolution
Range
Description of resolution bandwidth: signal resolution ability
is determined by IF filter's bandwidth, i.e. resolution
bandwidth. When signal goes through IF filter, spectrum
analyzer sweeps band-pass shape of IF filter by signal.
Therefore, frequencies of two uniform-amplitude signals
are very close, which may cause the top of band-pass
shape swept by any signal is almost covered by the other
signal, so it seems like one signal. If two signals are not
with uniform amplitude, but their frequencies are still very
close, then small signal possibly is flooded with large signal.
Resolution bandwidth function is used to select right IF
bandwidth during measurement. We take filter's 3dB
bandwidth as its resolution bandwidth, and the following
contents will tell you how to select right resolution
bandwidth.
4.2.1 Distinguish two signals with uniform amplitude
Generally, if you want to distinguish two signals with
uniform amplitude, resolution bandwidth must be less than
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