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Digital Logarithmic to Scientific Notation Converter

IP.com Disclosure Number: IPCOM000074842D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Clark, HW: AUTHOR

Abstract

Logarithmic instruments are desirable for automatic testing because of their large dynamic range; but, are not widely used because their output is not directly readable.

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Digital Logarithmic to Scientific Notation Converter

Logarithmic instruments are desirable for automatic testing because of their large dynamic range; but, are not widely used because their output is not directly readable.

The circuit schematically shown automatically converts a logarithmic signal to a directly readable display. This display is capable of handling full range of the input signal without the necessity of range changing switches or instruments.

An output signal VO, which may be either positive or negative, of a logarithmic testing instrument is fed to a polarity sensor 10, which measures the polarity of the signal and displays it as a plus or minus in the polarity sign display portion 12 of an indicator 14. Simultaneously, the signal VO is applied to an absolute value and scaling amplifier 15 that converts every input signal regardless of polarity to a positive polarity and amplifies it to a predetermined level. The positive output signal of amplifier 15 is then introduced into a binary- coded decimal, analog-to-digital converter 16 which converts the signal to a binary-coded decimal. The most significant decade of the digital output signal of converter 16 represents the characteristic of logarithm and is directly displayed as the power of 10 in the exponent display portion 17 of indicator the mantissa of the logarithm.

However, a binary-coded decimal output is not compatible with presently available antilogarithm amplifiers. It therefore becomes ne...