| 摘要 |
A digital time dependent relay is constructed for long time-lags and converts an incoming current signal into a binary number (n). The relay comprises one or more binarily controlled frequency multipliers, such as a Binary Rate Multiplier, or Decade Rate Multiplier, the control signal of which consists of the binary number and an input frequency which is determined by an adjustable oscillator and occurs when the incoming input signal exceeds a predetermined level. The output frequency of the multiplier is supplied to a binary counter which delivers an output signal when its contents reach a predetermined value. By a series-connection of two or more multipliers, an output frequency is achieved which is proportional to a second or higher power of the binary number and thus to the same power of the incoming current signal. The desired time-lag is determined by the frequency of the oscillator, by the control signal to the multiplier, and by the predetermined value of the counter. |
