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Circuit arrangement for generating an electric velocity signal

  • US 4,680,721 A
  • Filed: 11/28/1984
  • Issued: 07/14/1987
  • Est. Priority Date: 12/22/1983
  • Status: Expired due to Term
First Claim
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1. Circuit arrangement for generating an electric velocity signal which is proportional to the velocity of a moving part and particularly to the speed of rotation of a rotating part, consisting of two continuous input signals (w, v) which are periodically changeable as a function of the position of this moving part, and particularly of the angle of rotation (φ

  • ), and which are phase-shifted with respect to each other by approximately 90°

    , both having each in the mean the same frequency and a constant amplitude ratio and a sinusoidal or sine-like characteristic, a simple or integral multiple (N) of the duration of the period (T) of one input signal (w, v) being equal to the time in which the moving part covers a certain distance and particularly a rotating part carries out one full revolution, comprising;

    (a) an inversion circuit (1) for inverting the two input signals (w, v);

    (b) a curve change-over switch (2) having inputs for the input signals (w, v) and the inverted input signals (w, v) and having a first and a second output (3,

         4) which are connected in predeterminable sequence with respective similar sections of the input and inverted input signals, retaining their relative phase relationships, one signal sequence of periodically repetitive signal sections (x1 and x2, respectively) each appearing at the first and at the second output (3,

         4), which signal sections are in a range of values which is suitable for dividing the first signal section (x1) electrically by the second signal section (x2);

    (c) a dividing circuit (5) which is connected to the outputs (3,

         4) of the curve change-over switch (2) and which will divide in each case the signal section (x1) originating from the first output (3) by the signal section (x2) originating from the second output (4) whilst forming a sequence of quotient signals (y) which correspond to finite sections of a variation with time of a tangent function or of a tangent-like function of the path co-ordinate of the moving part and especially of the angle of rotation (α

    =N.φ

    );

    (d) a tangent/arc tangent converter circuit (7) which follows the divider circuit (5), for converting the quotient signals (y) into a sequence of path signals (z) which correspond to the arc tangent function or to an arc tangent-like function of these quotient signals (y) and in each case represent the variation of the path co-ordinates and particularly of the angle of rotation (α

    ) as a function of time (t) within successive intervals defined by the signal sections (x1, x2);

    (e) a first differentiating circuit (8) which follows the converter circuit (7), for differentiating the path co-ordinates represented by the path signals (z), particularly of the angle (α

    ) after time (t), a sequence of voltage sections us being formed which are interrupted by step positions and the voltage of which is proportional to the velocity of the moving part; and

    (f) a circuit (9) which blanks out the step positions and which supplies an analog voltage (u) which is proportional to the velocity of the moving part, said circuit (9) being connected to and processing the output of said differentiating circuit (8).

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