| 摘要 |
An improved frequency counter (10) for more reliably reading the frequency of low level signals by employing a method of separating the desired signal from undesirable noise related signals, wherein the frequency counter (10) comprises signal input amplifier circuitry (20), a frequency modulator circuit (30) for phase shifting the self-oscillation frequency of the undesired signal to isolate it from the valid signal, a prescaler circuit (40), a frequency or pulse counter (50) driven by the output of the self-oscillation frequencies from the main signal frequency so as to reduce false correlations between the self-oscillation, or noise, and valid signals.
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