A traditional Spectrum Analyzers works by making power versus frequency measurements by sweeping through the passband of its resolution bandwidth (RBW) filter. This Spectrum Analyzers China allows the detector circuit to calculate the power at each frequency point in the span. While this method provides high dynamic range, its disadvantage is that it can only calculate the amplitude data for one frequency point at any moment in time. Therefore measurements are only really valid if the signal of interests is relatively static. If the signal changes rapidly, such as during PLL tuning stage, there is a high probability of the analyzer missing critical information.