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Agenda

Agenda. Overview: What is spectrum analysis? What measurements do we make? Theory of Operation: Spectrum analyzer hardware Specifications: Which are important and why? Features Making the analyzer more effective Summary Appendix. Overview Types of Tests Made. Modulation. Noise.

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Agenda

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  1. Agenda • Overview: • What is spectrum analysis? • What measurements do we make? • Theory of Operation: • Spectrum analyzer hardware • Specifications: • Which are important and why? • Features • Making the analyzer more effective • Summary • Appendix Spectrum Analyzer Basics

  2. Overview Types of Tests Made . Modulation Noise Distortion Spectrum Analyzer Basics

  3. Overview Frequency versus Time Domain Amplitude (power) frequency time Time domain Measurements Frequency Domain Measurements Spectrum Analyzer Basics

  4. Overview Different Types of Analyzers Fourier Analyzer Parallel filters measured simultaneously A LCD shows full spectral display f f f 2 1 Spectrum Analyzer Basics

  5. f f 2 1 Overview Different Types of Analyzers Swept Analyzer Filter 'sweeps' over range of interest A LCD shows full spectral display f Spectrum Analyzer Basics

  6. Theory of Operation Spectrum Analyzer Block Diagram RF input attenuator IF gain IF filter detector mixer Input signal Log Amp Pre-Selector Or Low Pass Filter video filter local oscillator sweep generator Crystal Reference CRT display Spectrum Analyzer Basics

  7. MIXER + f f f - f sig sig LO LO f sig f f sig LO f LO Theory of Operation Mixer input RF IF LO Spectrum Analyzer Basics

  8. IF FILTER Input Spectrum IF Bandwidth (RBW) Display Theory of Operation IF Filter Spectrum Analyzer Basics

  9. Theory of Operation Detector DETECTOR amplitude "bins" Positive detection: largest value in bin displayed Negative detection: smallest value in bin displayed Sample detection: last value in bin displayed Spectrum Analyzer Basics

  10. Theory of Operation Video Filter VIDEO FILTER Spectrum Analyzer Basics

  11. Theory of Operation Other Components LO SWEEP GEN frequency LCD DISPLAY RF INPUT ATTENUATOR IF GAIN Spectrum Analyzer Basics

  12. f s f f f - f f LO + LO s LO s f s f s f IF f LO 0 1 2 3 (GHz) Theory of Operation How it all works together Signal Range LO Range 0 1 2 3 (GHz) IF filter 0 1 5 6 4 2 3 mixer detector 3.6 6.5 input 3.6 sweep generator A LO f 6 5 LCD display (GHz) 4 3 3.6 6.5 Spectrum Analyzer Basics

  13. Theory of Operation Front Panel Operation Primary functions (Frequency, Amplitude, Span) Softkeys 8563A SPECTRUM ANALYZER 9 kHz - 26.5 GHz Control functions (RBW, sweep time, VBW) Numeric keypad RF Input Spectrum Analyzer Basics

  14. 8563A SPECTRUM ANALYZER 9 kHz - 26.5 GHz Specifications • Frequency Range • Accuracy: Frequency & Amplitude • Resolution • Sensitivity • Distortion • Dynamic Range Spectrum Analyzer Basics

  15. Specifications Frequency Range Low frequencies for baseband and IF Measuring harmonics 50 GHz and beyond! Spectrum Analyzer Basics

  16. Specifications Accuracy Absolute Amplitude in dBm Relative Amplitude in dB Frequency Relative Frequency Spectrum Analyzer Basics

  17. + _ Specifications Accuracy: Frequency Readout Accuracy Typical datasheet specification: Spans < 2 MHz: (freq. readout x freq. ref. accuracy + 1% of frequency span + 15% of resolution bandwidth + 10 Hz "residual error") Frequency Spectrum Analyzer Basics

  18. = = = = 260 Hz 4000 Hz 450 Hz 10 Hz 4720 Hz + _ Specifications Accuracy: Frequency Readout Accuracy Example Single Marker Example: 2 GHz 400 kHz span 3 kHz RBW -7 9 Calculation: (2x10 Hz) x (1.3x10 /yr.ref.error) 1% of 400 kHz span 15% of 3 kHz RBW 10 Hz residual error Total = Spectrum Analyzer Basics

  19. Specifications Resolution: Resolution Bandwidth 3 dB Detector Mixer 3 dB BW Input Spectrum IF Filter/ Resolution Bandwidth Filter (RBW) LO Sweep RBW Display Spectrum Analyzer Basics .

  20. Specifications Resolution: RBW Type and Selectivity 3 dB 3 dB BW 60 dB 60 dB BW 60 dB BW Selectivity = 3 dB BW Spectrum Analyzer Basics

  21. Specifications Resolution: RBW Type and Selectivity RBW = 1 kHz Selectivity 15:1 RBW = 10 kHz 3 dB distortion products 7.5 kHz 60 dB 60 dB BW = 15 kHz 10 kHz 10 kHz Spectrum Analyzer Basics

  22. Specifications Resolution: Residual FM Residual FM "Smears" the Signal Spectrum Analyzer Basics

  23. Specifications Resolution: Noise Sidebands Phase Noise Noise Sidebands can prevent resolution of unequal signals Spectrum Analyzer Basics

  24. Penalty For Sweeping Too Fast Is An Uncalibrated Display Specifications Resolution: RBW Determines Measurement Time Swept too fast Spectrum Analyzer Basics

  25. Specifications Sensitivity/DANL Effective Level of Displayed Noise is a Function of RF Input Attenuation signal level 10 dB Attenuation = 20 dB Attenuation = 10 dB Signal-To-Noise Ratio Decreases as RF Input Attenuation is Increased Spectrum Analyzer Basics

  26. Specifications Sensitivity/DANL Sensitivity is the Smallest Signal That Can Be Measured 2.2 dB Signal Equals Noise Spectrum Analyzer Basics

  27. Specifications Sensitivity/DANL For Best Sensitivity Use: • Narrowest Resolution BW • Minimum RF Input Attenuation • Sufficient Video Filtering(Video BW < .01 Res BW) Spectrum Analyzer Basics

  28. LCD-DISPLAY RANGE 80 dB BANDWIDTH OR INCREASING ATTENUATION Specifications Dynamic Range +30 dBm MAXIMUM POWER LEVEL -10 dBm MIXER COMPRESSION THIRD-ORDER DISTORTION -35 dBm MEASUREMENT 145 dB -45 dBm SECOND-ORDER DISTORTION RANGE SIGNAL/NOISE 105 dB RANGE NOISE SIDEBANDS 0 dBc SIGNAL /3rd ORDER DISTORTION 80 dB RANGE SIGNAL/ 2nd ORDER 60 dBc/1kHz DISTORTION SIGNAL/NOISE SIDEBANDS 70 dB RANGE -115 dBm (1 kHz BW & 0 dB ATTENUATION) MINIMUM NOISE FLOOR Spectrum Analyzer Basics

  29. 10 dB/ MARKER MARKER 1 kHz 1 kHz -26 dBc -26 dBc CENTER 100 MHz SPAN 10 kHz Features Modulation Measurements: FFT Swept Frequency Domain FFT Frequency Domain LIN CENTER 100 MHz SPAN 0 Hz Spectrum Analyzer Basics

  30. 8563A SPECTRUM ANALYZER 9 kHz - 26.5 GHz Features Modulation Measurements: AM/FM Detector with Speakers Spectrum Analyzer Basics

  31. 8563A SPECTRUM ANALYZER 9 kHz - 26.5 GHz 1.025 MHz MKR AVG 10 -135.75 dBm/Hz Features Noise Measurements: Noise Marker & Video Averaging Spectrum Analyzer Basics

  32. CRT Display Features Stimulus Response: Tracking Generator Receiver Source DUT Spectrum Analyzer RF in IF LO DUT TG out Tracking Adjust Tracking Generator Spectrum Analyzer Basics

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