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Extended Function Capability for 4 Function Calculators

IP.com Disclosure Number: IPCOM000080457D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Saia, J: AUTHOR

Abstract

An existing conventional simple 4-function electronic calculator is modified by additional components, to perform additional powerful mathematical functions such as trigonometric, exponential and algebraic functions.

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Extended Function Capability for 4 Function Calculators

An existing conventional simple 4-function electronic calculator is modified by additional components, to perform additional powerful mathematical functions such as trigonometric, exponential and algebraic functions.

The drawing shows an existing calculator and, to the right, the added components consisting of a CONTROL STORE, and EXTENDED FUNCTION KEY, and a KEYBUS connecting the added components to the existing calculator. The CONTROL STORE is a device which essentially consists of an array of binary data that is addressable and capable of driving the KEYBUS, which consists of a group of wires or conductors that connect the existing calculator keyboard to the outputs of the CONTROL STORE. The EXTENDED FUNCTION KEY is a key which is depressed to initiate a CONTROL STORE action, so as to perform one of the additional mathematical functions.

The pressing of keys on the existing keyboard may be simulated by applying signals to the wires or conductors connecting the keys to the logic device. Thus, according to the figure, a CONTROL STORE may have output signals (KEYBUS), which are impressed upon the existing conductors between the keyboard and logic device of the existing calculator. If the EXTENDED FUNCTION KEY enables the CONTROL STORE to execute a sequence resulting in the `OPERATOR' and `END-UP' sequence to be described below in connection with TABLE 1, then the extended function will be automatically computed and displayed.

A simple 4-function calculator (add+, subtract-, multiply x, and divide/) may be used to compute a variety of special functions. A factoring method can be applied to power series which synthesizes to the four functions available on simple calculators.

For example, consider the power series for generating e/a/, the base of natural logarithms raised to the power a. The term `a' is commonly called the argument of the function.

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If this factored series is interpreted from left to right, then e/a/ can be directly computed on a 4-function calculator with the following sequence of key strokes:

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where: 1 means `strike the digit 1 key' x means `strike the multiply function key' a means `strike the digit key(s) according to the argument, a' / means `strike the divide function key' (N) means `strike the digit(s) N key(s)'...