HP 5980-3081EN free download

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Agilent Performance Spectrum Analyzer Series Swept and FFT Analysis Application Note Spectrum analysis measurements The Agilent Technologies perform- The PSA series cannot eliminate the often involve trade-offs between ance spectrum analyzer (PSA) trade-offs described above, as some accuracy, speed and dynamic range. series (model E4440A) provide of them are due to the inherent limi- In most cases, emphasis on one of major improvements in each of tations of measurement physics. these parameters adversely impacts these three measurement factors of However the innovations in digital the other two. For example, the wide speed, dynamic range and accuracy. filtering (a digital implementation of resolution bandwidths (RBW) used They also offer major increases a traditional swept IF section) and to achieve fast measurement speeds in ease-of-use and measurement fast Fourier transform (FFT) analysis result in higher noise levels and reliability. These improvements are of the PSA series provide the user potentially reduce dynamic range. primarily the result of an innovative with a dramatic improvement in the Increasing the sweep rate improves hardware and firmware architecture, trade-offs required. measurement speeds for a given based on an analog foundation of RBW but reduces accuracy due to exceptional performance. In addition, This product note will describe the inadequate settling time for the the autocoupling implemented in the use of FFT and swept analysis in intermediate frequency (IF) filters. PSA's firmware provides an easier the PSA series, along with the impli- Alternatively, dynamic range may be and more reliable path to high cations for measurement speed, emphasized at the expense of meas- quality measurements. accuracy, and dynamic range. It will urement speed because of the need summarize the autocoupling func- to use narrow (slow sweeping) RBW tions and demonstrate how to tune filters and, in some cases, averaging. them to optimize one or more of the major measurement parameters described here. Table of Contents Comparing the Amplitude Accuracy of Comparing the Amplitude Accuracy of Swept and FFT Techniques 2 The PSA series analyzers use both