A decimal product accumulator

As a step towards a digital correlator, a machine has been built which accumulates the sum of products of pairs of numbers. This device can determine the correlation between two series of numbers, provided all terms in the series are positive. The arithmetic operations are performed by dekatrons. To minimize multiplication time each product is formed in an asynchronous cycle whose duration is governed by the value of the digits in the multiplier factor. The speed of the present model is limited by relays which control the programming cycle. Given pairs of numbers having two decimal digits each, the machine accumulates 100 products per minute.