Introduction to SIGNAL ANALYZERS


Guide to Spectrum and Signal Analysis
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Summary of Contents

Guide to Spectrum and Signal Analysis

  • | 17Signal AnalyzersSignal analyzers incorporate a wide bandwidth digitizer in the IF to capture a time block of spectrum for analysis. Frequency, time and phase relationships of signals can be analyzed within the bandwidth and time limits of the captured spectrum. Digital modulation can be characterized in many ways not possible with a swept tuned spectrum analyzer. Figure 17 compares the block diagrams for a spectrum analyzer and signal analyzer. Figure 18 show example time blocks of spectrum with a variety of modulations. A signal analyzer is often used to measure the characteristics of analog and digital modulation. Figure 18tttt1010AmplitudeFrequencyPhaseBoth Amplitudeand PhaseDigital BasebandModulation SignalDigital DataU(t) = U(t) • sin(2πfct + φ(t))AMFMPMInputSignalRF InputAttenuatorMixerADCDDCDisplayCPU / FFTI / QPre-selector, orLow-pass FilterSynthesizerReferenceOscillatorInputSignalRF InputAttenuatorSpectrumAnalyzerSignalAnalyzerMixerIF GainIF FilterHorizLog AmpEnvelopeDetectorVideoFilterADCVertDisplayCPUPre-selector, orLow-pass FilterStepSynthesizerReferenceOscillatorFigure 17