GB816454A - Apparatus for determining the time integral of an electrical time-varying quantity - Google Patents

Abstract

816,454. Electric analogue calculating. BOFORS A.B. Feb. 6, 1957 [March 24, 1956], No. 4094/57. Class 37. Apparatus determining the time integral of a voltage signal, comprising an integrating device to whose input the signal is to be supplied, developing at its output a signal representing the integral of the voltage signal for application to a continuous permanent magnitude recording device; there being provided a voltage-sensitive zeroizing device supplied with the integrated signal which periodically sets the integrating device to zero when the signal reaches a predetermined value corresponding to the maximum value signal to which recording device is responsive. A timevariable electrical signal (Fig. 1, not shown) is applied to terminals 2, 3 (Fig. 3) to feed a squaring circuit 4 comprising (Fig. 4) parallel channels 13, 14 containing series resistances 15, 30 and groups of three shunt channels 16, 17, 18 ; 31, 32, 33 respectively grounding each series channel and each containing in series a diode, a resistance, and a biasing voltage source; the diodes being appropriately poled and biased and the resistances being so proportioned that the outputs at terminals 28, 29 represent the squared value of the input signal on positive and negative excursions (Figs. 2, 5, not shown). These outputs are connected in series with resistor 5 to electron tube amplifier 6, shunted from output to input by a capacitor 7 and normally open contacts 9, 10 operated by a relay shunted across the output, which is connected to a pen recorder 12. The input variable is squared at 4 and integrated by amplifier 6, resistor 5, and capacitor 6 to operate pen recorder 12 to describe on a continuously moving tape the curve of the integral 47 (Fig. 6). At a fixed voltage value of the output, relay 11 operates to short-circuit the integrator at 48 so that the integration curve restarts from zero at 49. The integration curve may be described by dissecting the tape and juxtaposing the sections so that line 47 is continuous, and its mean slope may be designated by a straight line 50 through two arbitrary time values to indicate the square of the mean value of the variable. The device may be responsive to, e.g., a time varying signal representing the output accelerations of a servo-system to determine the R.M.S. value of the deviations thereof from a mean value. Specification 799,984 is referred to.