Basis of Spectrum Analyzers Technical Note Guide

Basis of Spectrum Analyzers Technical Note Guide
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Basis of Spectrum Analyzers Technical Note Guide

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    Technical Note The Basis of Spectrum Analyzers

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    1 Slide 1SpectrumAnalyzer-E-E-1The Basis of Spectrum AnalyzersAnritsu CorporationVer.3.1 Slide 2SpectrumAnalyzer-E-E-1             Contents1. What is a Spectrum Analyzer?2. Measurement Categories3.  Principals of a Spectrum Analyzer4.  Characteristics4.1 Suitab...

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    2 Slide 3SpectrumAnalyzer-E-E-1A measuring instrument that displays an electrical signal according to its frequency.Each frequency component contained in the input signal is displayed as a signal level corresponding to that frequency.1. What is a Spectrum Analyzer?MS268x SeriesMS266x SeriesMS2711...

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    3 Slide 5SpectrumAnalyzer-E-E-1Frequency Power (dBm) (W) f0 -10dBm 0.1mW2f0 -20dBm0.01mw3f0-54dBm 4.0nW(Sum) 0.11mWDescribing Electrical SignalsPower 0.11mW (-9.6dBm)Oscilloscope waveformsSpectrum analyzer waveforms Slide 6SpectrumAnalyzer-E...

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    4 Slide 7SpectrumAnalyzer-E-E-1Time Domain• Changes in time can be seen.• If a signal has many frequency elements, the analysis is difficult.Frequency Domain• Each element of a complex signal can be separated easily. • Low-level distortion signals can be detected. • Spurious elements ca...

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    5 Slide 9SpectrumAnalyzer-E-E-1Block Diagram of the Super-Heterodyne Method3. Principals of a Spectrum AnalyzerATTIF filter(RBW)MIXLocalOscillatorDetectorVideo filter(VBW)A/DCPUMemoryA/DSweep generatorInput Signal Slide 10SpectrumAnalyzer-E-E-14. Characteristics4.1 Suitable Input Level4.2 Maxi...

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    6 Slide 11SpectrumAnalyzer-E-E-1When the signal and local oscillator are added at the mixer input, the suitable input level is the distortion level specification that doesn't influence the measurement. The level relationship between the input signal and the distortion is specified at the mixer i...

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    7 Slide 13SpectrumAnalyzer-E-E-1The measurement frequency range is determined by the center frequency of the IF filter and the local oscillator frequency range.Input Signal Freq. = Local Signal Freq. – IF Freq.The input signal and the local signal are mixed by the mixer. The mixer output is f...

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    8 Slide 15SpectrumAnalyzer-E-E-1-108dBc/Hz at offset 10kHz-120dBc/Hz at offset 100kHzF0=1GHz, Offset 10kHz, RBW 300Hz, VBW 10HzF0=1GHz, Offset 100kHz, RBW 10kHz, VBW 10HzSideband Noise: –87dBc / 300Hz -112dBc / HzSideband Noise: –84dBc / 10kHz -124dBc / HzOffset 10kHzOffset 100kHzcarriercarr...

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    9 Slide 17SpectrumAnalyzer-E-E-1e.g The specification of MS8609A: Selectivity <15 : 1When a narrow RBW is selected, the 3dB bandwidth and 60dB bandwidth become small, the frequency resolution is greater, the average noise level falls, and you can see low-level signals. 60dB BandwidthSelectivit...

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    10 Slide 19SpectrumAnalyzer-E-E-1Normal: Displays both the maximum level and the minimum level present between the current sample point and the next sample point.Pos Peak: Displays the maximum level present between the current sample point and the next sample point. Pos Peak is used to measure th...

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    11 Slide 21SpectrumAnalyzer-E-E-1When an early frequency change is seen, such as in pulsed noise, the Sample mode is used. 4.7 Detection methods Slide 22SpectrumAnalyzer-E-E-1When a small signal included in noise is measured, this effect is demonstrated. e.g The specification of MS8609A: 1Hz to...

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    12 Slide 23SpectrumAnalyzer-E-E-1It is the range that can be measured without making it suffer in the noise level, residual responses, and distortion. However, there is no definition common to all manufacturers, and the value is different depending on what it is based on.(1) Average Noise Level(...

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    13 Slide 25SpectrumAnalyzer-E-E-1The average noise level changes with RBW and ATTRBW30kHz10kHz3kHz1kHzATT60dB50dB40dB30dB20dB10dBChanging RBWChanging ATTThe average noise level increases 10dB when RBW value is changed from 1kHz to 10kHz. The average noise level changes by 10dB when ATT value is c...

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    14 Slide 27SpectrumAnalyzer-E-E-1(3) 2nd harmonic DistortionThe 2nd harmonic and the 3rd harmonic of the input signal occur by the mixer generating distortion when a high level signal is input to the mixer.f0 f2 f3f0 f2 f310dB20dB30dBWhen a basic waveform is enlarged b...

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    15 Slide 29SpectrumAnalyzer-E-E-1(4) Two-tone 3rd Order DistortionWhen two high-level signals with nearby frequencies are input to the mixer, the two signals influence each other. As a result, a frequency not contained in the input signal appears. These phenomena are called Two-tone 3rd Order Di...

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    16 Slide 31SpectrumAnalyzer-E-E-14.9 Dynamic RangeABC-30dBmA: Average noise≤ -121dBm(f0=2GHz, RBW300Hz)B: Residual response≤ -100dBm (2GHz band)C: 2nd harmonic distortion≤ -90dBc at MIX input -10dBmA: Average noise-30dBm –(-121dBm) = 91dB / RBW300Hz 116dB / RBW1HzB: Residual response...

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    Anritsu Corporation5-1-1 Onna, Atsugi-shi, Kanagawa, 243-8555 JapanPhone: +81-46-223-1111Fax: +81-46-296-1264• U.S.A.Anritsu Company1155 East Collins Blvd., Richardson, TX 75081, U.S.A.Toll Free: 1-800-267-4878Phone: +1- 972-644-1777Fax: +1-972-671-1877• CanadaAnritsu Electronics Ltd.700 Silv...