Abstract: 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 (V.sub.0) 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.

Abstract: A simulated ohms generating method and apparatus for calibrating electrical measuring instruments of the resistance and/or conductance measuring type are disclosed. First, the nature (current or voltage) of the internal power supply of the measuring instrument is determined by sequentially connecting two different resistors to the terminals of the instrument and determining if the current flow through the resistors changes (voltage source) or remains constant (current source). Depending upon the nature of the power supply one or the other of two sequences of steps are followed. While the sequences are somewhat different, they both include adjusting the output of a voltage source connected in series with a fixed resistor and applying the combination to the instrument to simulate a predetermined resistance (ohms) value. After this value is set, the instrument being calibrated is read to determine if the reading is the same as the predetermined resistance value being simulated.