A Time-Division Multiplier

A time-division multiplier for analog computers is described. Its features, for a switching pulse frequency of 2,000 cycles per second, are as follows: an accuracy of one part in a thousand, a pass band of 2 cycles per second, an input impedance of one megohm, and a very low output impedance (the output impedance of a feedback amplifier). This multiplier has the following advantages when compared to two other types of analog multipliers: a) an accuracy limited solely by the stability of the components used and the fineness of the adjustments that can be made; b) a pass band greater than that of servo-mechanism multipliers; c) a much smaller amount of material than is necessary for diode multipliers with translators having parabolic characteristics and adjustments which can be made much more rapidly (although requiring a certain amount of practice); d) the possibility of changing the diodes without having to repeat all the adjustments. These results have been obtained by the development of a precision electronic switch and by compensation of the stray capacities of the tubes.