| 摘要 |
A converter capable of accurately and rapidly converting an input signal whose frequency varies as a function of a parameter being metered into a bit parallel number for manipulation by a digital computer. The incoming signal, before being applied to the converter, is shaped to produce a continuous train of square wave periods, each beginning with a leading edge. A measurement is made during a time interval which need not be synchronized with the input signal and is independent of its frequency, the interval having a fixed duration which is a predetermined multiple of a given unit of time. In this interval, the following factors are measured in the slice of the square wave train falling between the start and finish points of the interval: the number of time units occurring between the start point and the leading edge of the first complete wave period in the slice; the number of complete wave periods lying within the slice, and the number of time units occurring between the last leading edge appearing in the slice and the finish point. The measured factors are applied to the digital computer which determines the frequency of the incoming signal in binary terms from the equation relating frequency to these factors. |
