| 摘要 |
A circuit for providing an indication of watt-hours from a voltage input that is an analog of watts comprises a source of a high-frequency square wave and a precision triangular wave at a frequency that is derived from the high-frequency square wave by frequency division. A time interval is derived by selecting a period between a time when the triangular wave crosses zero volts and the time at which the amplitude of the triangular wave equals the analog input voltage. A count of the number of cycles of the high-frequency signal during that interval provides a measure of the value of the input voltage, and a continuing count of that number of cycles provides a time-integrated value of the count. When the input signal is analogous to watts, the integrated output provides a measure of watt-hours.
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