| 摘要 |
A method of converting a pulse train of electrical signals having a frequency within a known frequency range into digital signals is shown. The method comprises the steps of deriving with a phase-locked loop the frequency of the electrical signals and producing clock pulses at a frequency which is a preselected integer of the electrical signals frequency; deriving an analog input signal from the electrical signals; receiving and counting clock pulses with a pulse scaling circuit for producing count enabling signals; detecting with a peak detecting circuit having a comparator receives as inputs the analog input signal and a analog output signal voltage and an output coupled to and enabling the pulse scaling circuit; producing with a digital counting circuit which is responsive to count enabling signals by changing count direction discrete digital output signals which are stored in a latch register at the time the digital counting circuit changes its count direction; applying the discrete digital output signals to a digital-to-analog converter which produces the analog output signal voltage; and comparing with the comparator the analog input signal with the analog output signal voltage for enabling the digital counting circuit as long as the analog input signal is of a greater magnitude than the analog output signal voltage, and when this condition is reversed, the digital counting circuit is reversed in counting direction, and the binary value thereof is stored in the latch register.
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