Agilent Spectrum Analysis Basics - Agilent Technologies

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RF designers are often concerned with the noise figure of their devices, as this directly affects the sensitivity of receivers and other systems. Some spectrum analyzers, such as the PSA Series and ESA-E Series models, have optional noise figure measurement capabilities available. This option provides control for the noise source needed to drive the input of the device under test (DUT), as well as firmware to automate the measurement process and display the results. Figure 8-2 shows a typical measurement result, showing DUT noise figure (upper trace) and gain (lower trace) as a function of frequency. For more information on noise figure measurements using a spectrum analyzer, see Agilent Application Note 1439, Measuring Noise Figure with a Spectrum Analyzer, literature number 5988-8571EN. Figure 8-2. Noise figure measurement Similarly, phase noise is a common measure of oscillator performance. In digitally modulated communication systems, phase noise can negatively impact bit error rates. Phase noise can also degrade the ability of Doppler radar systems to capture the return pulses from targets. Many Agilent spectrum analyzers, including the ESA, PSA, and 8560 Series offer optional phase noise measurement capabilities. These options provide firmware to control the measurement and display the phase noise as a function of frequency offset from the carrier, as shown in Figure 8-3. 104 Figure 8-3. Phase Noise measurement
Digital modulation analysis The common wireless communication systems used throughout the world today all have prescribed measurement techniques defined by standardsdevelopment organizations and governmental regulatory bodies. Optional measurement personalities are commonly available on spectrum analyzers to perform the key tests defined for a particular communication format. For example, if we need to test a transmitter to the Bluetooth wireless communication standard, we must measure parameters such as: • Average/peak output power • Modulation characteristics • Initial carrier frequency tolerance • Carrier frequency drift • Monitor band/channel • Modulation overview • Output spectrum • 20 dB bandwidth • Adjacent channel power These measurements are available on the Agilent ESA-E Series spectrum analyzer with appropriate options. For more information on Bluetooth measurements, please refer to Agilent Application Note 1333, Performing Bluetooth RF Measurements Today, literature number 5968-7746E. Other communication standards-based measurement personalities available on the ESA-E Series include cdmaOne and GSM/GPRS/EDGE. Measurement capabilities for a wide variety of wireless communications standards are also available for the PSA Series spectrum analyzers. Optional measurement personalities include: • GSM/EDGE • W-CDMA •HSDPA • cdma2000 • 1xEV-DO • 1xEV-DV • cdmaOne • NADC and PDC • TD-SCDMA Figure 8-4 illustrates an error vector magnitude (EVM) measurement performed on a GSM/EDGE signal. This test helps diagnose modulation or amplification distortions that lead to bit errors in the receiver. Figure 8-4. EVM measurement results and constellation display 105
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Agilent Spectrum Analysis Basics Ap
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Table of Contents — continued Cha
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Some measurements require that we p
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Figure 1-3. Harmonic distortion tes
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While we have defined spectrum anal
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Since the output of a spectrum anal
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We need to pick an LO frequency and
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To separate closely spaced signals
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Agilent data sheets describe the ab
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This allows us to calculate the fil
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Some modern spectrum analyzers allo
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On the other hand, the rise time of
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The width of the resolution (IF) fi
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The “bucket” concept is importa
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Peak (positive) detection One way t
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The normal detection algorithm: If
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EMI detectors: average and quasi-pe
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The effect is most noticeable in me
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Thus, the display gradually converg
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In some cases, time-gating capabili
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Timeslots 0 1 2 3 4 5 6 7 Timeslots
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Gated sweep Gated sweep, sometimes
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In Chapter 2, we did a filter skirt
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Custom signal processing IC Turning
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Chapter 4 Amplitude and Frequency A
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Following the input filter are the
Page 53 and 54: Improving overall uncertainty When
Page 55 and 56: Examples Let’s look at some ampli
Page 57 and 58: In a factory setting, there is ofte
Page 59 and 60: Because the input attenuator has no
Page 61 and 62: Noise figure Many receiver manufact
Page 63 and 64: Using these expressions, we’ll se
Page 65 and 66: Let’s first test the two previous
Page 67 and 68: This is the 2.5 dB factor that we a
Page 69 and 70: When we add a preamplifier to our a
Page 71 and 72: 2D dB 3D dB 3D dB 3D dB With a cons
Page 73 and 74: We can construct a similar line for
Page 75 and 76: Figure 6-2 shows the dynamic range
Page 77 and 78: Dynamic range versus measurement un
Page 79 and 80: Let’s see what happened to our dy
Page 81 and 82: The range of the log amplifier can
Page 83 and 84: Chapter 7 Extending the Frequency R
Page 85 and 86: Next let’s see to what extent har
Page 87 and 88: In examining Figure 7-5, we find so
Page 89 and 90: Can we conclude from this discussio
Page 91 and 92: Amplitude calibration So far, we ha
Page 93 and 94: From the graph, we see that a -10 d
Page 95 and 96: Pluses and minuses of preselection
Page 97 and 98: Table 7-1 shows the harmonic mixing
Page 99 and 100: Figure 7-15. Which ones are the rea
Page 101 and 102: Figure 7-18. The image suppress fun
Page 103: Other examples of built-in measurem
Page 107 and 108: Data transfer and remote instrument
Page 109 and 110: Summary The objective of this appli
Page 111 and 112: Delta marker: A mode in which a fix
Page 113 and 114: Frequency stability: A general phra
Page 115 and 116: LO feedthrough: The response on the
Page 117 and 118: Residual responses: Discrete respon
Page 119 and 120: Video: In a spectrum analyzer, a te
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