Method of and system for metering a periodically varying voltage
US4075558A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1976 |
| Grant date | Feb 21, 1978 |
| Priority date | — |
| Expiry date | Sep 7, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The average amplitude of an incoming signal voltage of variable frequency is measured by half-wave rectification of that signal voltage to produce a pulsating current which is subtracted from a continuous current in the input of an integrating amplifier. The fluctuating output voltage of this amplifier is periodically sampled, once per cycle of the signal voltage, to provide a train of corrective pulses. These pulses are accumulated to provide a reference voltage fed to a differential amplifier which controls the continuous current in response to differences between this reference voltage and a feedback voltage proportional to that current to compensate for changes in average signal amplitude. The magnitude of the continuous current, read by a meter, is therefore a measure of the desired amplitude. The voltage samples may be weighted, in proportion to signal frequency, by a variable-gain amplifier or a sampling switch closed for different periods in the output of the integrating amplifier referred to. A second integrating amplifier, in cascade with the first one, may receive the voltage samples and store them on one of two series-connected condensers in its feedback circuit, the ot…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.