| 摘要 |
A method and apparatus for enhancing the output of a log-antilog type root-mean-square (RMS) converter by correcting the RMS converter output for nonlinearities in the AC/DC transfer characteristic of the converter are disclosed. First, preselected positive and negative DC voltages near the upper and lower ends of the range of the RMS converter are applied to the RMS converter and the output of the converter is measured by a voltage measuring instrument for each applied voltage. The applied and measured voltage values are used to determine the positive and negative gain (G) and offset voltage (V0) characteristics of the RMS converter. The characteristic information is used to correct (e.g., enhance) the output of the RMS converter when AC voltages falling within the range of the converter are later applied. The same procedure is followed for each range of the RMS converter, if the RMS converter has multiple ranges. Further enhancement is provided by correcting for gain errors resulting from crest factor variations. Crest factor variation enhancement is provided by applying preselected square waves to the converter and measuring the output of the converter. The measured output voltages are utilized to determine the positive and negative gain crest factor correction constants, which are used to correct the positive and negative gain characteristics of the RMS converter.
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