Real-Time Signal Analysis

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					        Real-Time Signal Analysis



    TRIGGER       CAPTURE      ANALYZE




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                             Tektronix Partner Business
    Tadeusz Asyngier         Rheingoldstrasse 50
    M.Sc.E.E.
    Application Consultant   CH-8212 Neuhausen am Rheinfall
    D&M NE Region EMEA
                             tel:          +41 52 675 37 72
                             GSM:   +48 606 218 757
                             email:        tadeusz.asyngier@tek.c




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    Agenda
     Measurement Challenges
     New tools for testing: Real Time Spectrum Analyser (RTSA)
     RTSA example applications




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    Evolution of Signal Analysis Techniques
                               SA
                                                            VSA
                                                                                           RTSA
                              1960s                         1990s                           TODAY

    Market         • Military                 •   Encryption                     • Congested RF spectrum
    Drivers        • Communication systems    •   Military signal intelligence   • Pervasiveness of low cost RF
                                                                                   in consumer electronics
                   • Emerging solid state     •   Cell phones
                                                                                 • Growth of DSP-based,
                     technology               •   Complex digital modulation       modulation-agile
                                                                                   communication systems

    Measurement • High frequency              • Digital Demodulation             • Time-varying, bursted,
    Challenges    measurements                • Emergence of Standards             and transient RF signals
                   • Analog modulation                                           • Complexity of wireless
                                                                                   communication standards

    Solutions      • RF power vs. frequency   • Digital modulation               • Frequency domain trigger
                   • Low noise floor            analysis                         • Seamless capture of RF
                   • High dynamic range                                            signals changing over time
                                                                                 • Flexible time-correlated
                                                                                   multi-domain analysis


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    Simplified Analyzer Block Diagrams
     Swept
     Tuned
    Spectrum
    Analyzer
      (SA)




      Vector
      Signal
     Analyzer




                                                Modern FFT Based Analyzers
      (VSA)




                     The Real-Time Difference

    Real-Time
    Spectrum
     Analyzer
      (RTSA)




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    Real-Time Spectrum Analyzer (RTSA)




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    Swept vs. Real-Time Seamless Capture
                Swept           Real-Time
               Analyzers        Analyzers




                                            TIME




             FREQUENCY         FREQUENCY


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    Frequency Mask Trigger

     Define a frequency
      mask which can be
      used to trigger on
      specific events in the
      frequency domain


     Reliably detect and
      capture elusive RF
      signals that a level
      trigger cannot see in
      a crowded spectral
      environment



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    Frequency Mask Trigger (FMT)

     Complex Spectral Environments

     EW, Jammers, LO Leakage, etc.

     Desired Signal Below Others…

     Frequency Mask Trigger Solution

     Stretch Mask Around Irrelevant

     Real-Time FFT & Mask Compared

     Anything Above Mask Triggers!


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     Seamless Capture and Spectrogram

      The spectrogram
       shows how an RF
       signal changes over
       time in the frequency
       domain


      Frequency is the
       horizontal axis, time
       is the vertical axis,
       and power is
       represented by the
       color of the trace



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     Multi-Domain Time-Correlated View

     Before Interference                                                          During Interference

     Bluetooth   Microwave Oven   WLAN Signal            Interfering Bluetooth Signal




                                    WLAN Constellation        WLAN Error Vector         WLAN Constellation
                                    Synchronized              Measurement Degraded      Out of Synch


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     A New Approach to RF Signal Measurement
                            WLAN During Interference
                           WLAN Before Interference

        Bluetooth bursts                      WLAN Signal    Interfering Bluetooth Signal




                                                        WLAN Synchronized
                                                       WLAN Not Synchronized

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     Measurement modes
                SA measurements:
                   –   Real-time SA mode
                   –   Traditional SA mode
                   –   SA with spectrogram mode
                   –   RTSA with zoom

                DEMOD measurements:
                   –   Flexible analog modulation analysis
                   –   Flexible digital modulation analysis
                   –   Standards based modulation analysis




                TIME measurements:
                   –   Time domain transient analysis
                   –   Pulse signal measurement
                   –   CCDF analysis




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     RSA Family Banner Specifications

                 RSA2200A           RSA3300A            WCA200A           RSA3400A


                                     Frequency           Frequency         Frequency
     Trigger         Level
                                      & Power             & Power           & Power


                    10MHz              15MHz              15MHz              36MHz
                 Real-Time BW       Real-Time BW       Real-Time BW       Real-Time BW
     Capture
                -73dBc 3rd Order   -74dBc 3rd Order   -74dBc 3rd Order   -78dBc 3rd Order
                Dynamic Range      Dynamic Range      Dynamic Range      Dynamic Range

                                                                        Time, Frequency,
                                 Time, Frequency,     Time, Frequency,
                Time, Frequency,                                        Pulse, Analog &
     Analyze                     Analog & Digital     Analog & Digital
               Analog Modulation                                       Digital Modulation,
                                    Modulation        Modulation, 2-3G
                                                                          2-3G, WLAN


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General Purpose Analog and Digital
Demodulation




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     General Purpose Analog & Digital Demodulation
     QPSK Spectrum Analyzer View




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     General Purpose Analog & Digital Demodulation
     QPSK Spectrum Analyzer View




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     General Purpose Analog & Digital Demodulation
     QPSK IQ Frequency versus Time




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PLL Analysis




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     PLL Measurements: Phase Noise
      Phase Noise typically expressed
       as a ratio of sideband power in
       1Hz BW to the signal power
       (dBc/Hz)


      Phase Noise is measured at
       specific offsets from the a
       carrier frequency


      Measurement Example:
        –   CF = 2.4515 GHz
        –   Offset = 2 kHz
        –   Noise Bandwidth = 100 Hz
        –   C/N = 25.21 dB
        –   C/No = 45.21 dB



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     PLL Measurements: Spurious Signals
      There are many sources of
        spurious signals that can affect
        the output of a PLL
         –   Switching circuitry
         –   Power supply switching
         –   Close by oscillators
         –   IMD
      The reference signal can also
        generate spurious
         –   These spurious signals are always
             at multiples of the reference signal


      The loop filter can be used to
        reduce spurious, but in the real
        world, they can never be
        eliminated


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     Signal Source Analysis Measurements
     Random Jitter

                                                                     Jitter and phase
                                                                       noise are
                                                                       mathematically
                                                                       the same
                                                                     Calculate
                                                                       Random Jitter
                                                                       (Rj)
                                                                     Rj settling time
                                                                       is measured as
              Area of integrated RMS noise
                                                                       Rj vs time
                                                                     3.2 msec at
                                                                       threshold 2.5
                                                                       psec.

                                             Calculated from
                                             integrated RMS noise



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     Signal Source Analysis Measurements
     Frequency vs Time



                                                   Smoothing
                                                    function reduces
                                                    wideband noise
                                                    on the trace

                     Display of Frequency -Time




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     Frequency Hopping Transients

     Non-Overlapping FFT            Overlapping FFT




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Software Defined Radio Test




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     Correlated Multi-Domain Analysis


                                  I/Q
               PA
                               Modulator
                                                                 DSP

                    RF VCO




                                           Mixed Signal Source
    Real-Time
Spectrum Analyzer

                         Oscilloscope                             Logic Analyzer


            Frequency        Analog Time               Digital Time
             Domain            Domain                    Domain

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     Correlated Multi-Domain Analysis
     Software Defined Radio




      Trigger, capture, and analyze the RF signal and baseband
       modulation
      View correlated baseband analog and digital time domain data
       triggered from the frequency domain anomaly

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     Thank You




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