| 摘要 |
A method of digitally computing the square of the ratio of a variable measuring frequency fx to a constant base frequency fxo using a constant reference frequency fo, especially in measuring weights on a string-type scale by employing a measuring counter, a base time counter and a control counter, comprising the steps of simultaneously with the initiating of the counting operation producing a series of electrical pulses Ix with a frequency Fx proportional to the signal frequency fx, feeding this series of pulses to the measuring counter for a counting period comprising two counting phases the first one of which is set by the base time counter, producing a series of electrical reference pulses Io with a frequency Fo proportion to the base frequency fxo, feeding the reference pulses Io in excess of pulses Ix to the control counter which sets the second one of the counting phases, the measuring frequency fx after the beginning of the counting is fed to the measuring counter M over a first AND gate UI and over a second AND gate U2 to an input V of the control counter S also having a second input R, the reference frequency fo being fed to the second input R over a third AND gate U3, and also over a fourth AND gate U4 to the base time counter G which counts from zero up to a predetermined number and thereby sets the period T2 of the first counting phase during which an output signal of the base time counter is fed into the second and fourth AND gates U2, U4, such output signal keeping the second and fourth AND gates open during the first phase, the control counter S attaining a count during the fist counting phase which during the second counting phase determined by the time period T2 of the control counter S is reduced by the reference frequency fo to zero and, at the end of such time period T2 the first AND gate U1 becomes closed which has been kept open till the end of such time period T2 by an output signal of the control counter S. |
