Agilent 1951-08 free download

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HEWLETT-PACKARD JOURNAL T E C H N I C A L I N F O R M A T I O N F R O M T H E - h p - L A B O R A T O R I E S VOL. 2 No. 12 BLISHED BY THE HEWLETT-PACKARD COMPANY, 395 PAGE MILL ROAD, PALO ALTO, CALIFORNIA AUGUST, 1951 -hp- Distortion Measuring Equipment simple, straightforward measure- The measurement of harmonic distortion JL ment of harmonic distortion has always is based on the definition % distortion = been valuable in design, test, and production (Af + A' + A> + . . .) «/A, X 100, A! work. This basic measurement undoubtedly being the amplitude of the fundamental, A2 gives as much if not more information about the second harmonic, etc. Two methods for the operation of an amplifier as any other measuring distortion have evolved from this single measurement that can be made. In definition. In one method, the amplitude of spite of the development of more complex each frequency component appearing in the methods and equipment for measuring vari output of a device fed with a single pure fre ous effects of non-linear transfer characteris quency is measured with a special frequency- tics, the harmonic distortion measurement, selective voltmeter or wave analyzer. The because of its ease and simplicity, is still the measured values are then substituted in the predominant method in use; and the demand above expression. In the second method, the for equipment for such measurements is amplitude of a voltage containing harmonics greater than it has ever been. In electronic is first measured; then the fundamental is fil equipment, where the transfer characteristic tered out and the rms value of the combined of