Specifications

Chapter 10 289
Block Diagrams
RF Analyzer Section
Spectrum Analysis
The LO on the A2A20 Spectrum Analyzer is swept across the span by
the Controller, see Figure 10-6 on page 293. The LO starts sweeping
when the oscilloscope circuits on the A2A33 Measurement board trigger
the display sweep to start. As the LO sweeps, the spectrum analyzer
filters and then amplifies the IF signal in a logarithmic detector so the
signal voltage will be proportional to the log of power. The signal
voltage is measured by a sampler on the Measurement board and
displayed.
Spectrum analyzer resolution bandwidth is determined by switching
bandwidth IF filters on the A2A20 Spectrum Analyzer. These filters are
set by the Controller as a function of the span selected from the front
panel.