Coded data generation or conversion – Digital code to digital code converters – To or from mixed base codes
Reexamination Certificate
1999-08-19
2001-12-18
JeanPierre, Peguy (Department: 2819)
Coded data generation or conversion
Digital code to digital code converters
To or from mixed base codes
C341S155000, 36
Reexamination Certificate
active
06331828
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an analog/digital (A/D) converter which converts analog signals to digital signals, and a digital/analog (D/A) converter which converts digital signals to analog signals, as well as a signal conversion method to be used therein. More specifically, the above-described converters are characterized in that they use, as digital data signals, an independent notation system of three digit symmetric binary numbers (hereinafter referred to as HEN2). A combination of such signals is selected from a 2-based three digit redundant binary number with each signal being one of three digits {n, o, p} each representing a value {−1, 0, 1} as a one-digit signal. At least one of two adjacent digits at any digit position of one or more digits is zero (the signal “o”).
BACKGROUND OF THE INVENTION
As is well known, with most of the digital data signal processors according to the prior art, numbers of a two digit binary system using {0, 1} digit set are processed as digital data signals, and this is the same with A/D converters and D/A converters converting analog signals to digital data signals and vice versa.
Further, as is well known, with a part of digital computers, 2-based three digit redundant binary numbers using a three signal set {−1, 0, 1} as one digit are used for improvement. That is, to shorten operation time by an expected smaller frequency of carry digits than two digit binary numbers.
The Japanese Patent Application No. 133927/1998 (U.S. application Ser. No. 09/312,347) by the inventor has verified a one-to-one correspondence existing between the HEN2 (which is a combination of such signals, selected from a 2-based three digit redundant binary number with either one signal of three digits {n, o, p} each expressing a value {−1, 0, 1} as a one-digit signal. At least one of two adjacent digits at any digit position of one or more digits expresses zero (the signal “o”)) and 2-based two digit binary numbers using {0, 1} digit set. This correspondence may allow analog signals to be converted to digital data signals having two digit binary numbers and then to digital data signals of the HEN2 type with one-to-one correspondence. Further, the correspondence may allow digital data signals of the HEN2 to be converted to digital data signals of the two digit binary number with one-to-one correspondence, and then to analog signals. But, either case must go through digital data signals of the two digit binary numbers, thus resulting in a longer time for conversion and necessitating a reduction of conversion time.
Further, since HEN2 and two digit binary numbers are different in their value ranges even with the same number of digits, mutual conversions between digital data signals of HEN2 and analog signals by way of digital data signals of the two digit binary numbers may not make full use of the characteristics of the HEN2 as digital data signals, thus necessitating a direct conversion between analog signals and digital data signals of HEN2.
SUMMARY OF THE INVENTION
In view of the aforementioned problems, this invention intends to provide a signal conversion method and signal converters which can make direct conversion between analog signals and digital data signals of the HEN2 with a shorter conversion time than the prior art.
To solve the problems, this invention is a signal conversion method, which uses, as digital data signals, an independent notation system of HEN2, which is a combination of signals selected from a 2-based three digit redundant binary number with either one signal of three digits {n, o, p} each expressing value {−1, 0, 1} as a one-digit signal. At least one of two adjacent digits at any digit position of one or more digits is zero (the signal “o”). Between the above digital data signals and analog signals, at least one way or mutual conversions are made, so that direct conversion can be made between analog signals and digital data signals of the HEN2 with shorter conversion time than the prior art.
In another embodiment, a region of the analog signals to be converted is determined. Then, the determined region is equally divided into four sections. At quarter sections at both ends, the respective digits to which the digital data signals correspond are made “p” and “n”, while, at the intermediate two quarter sections, the respective digits are made “o”, to determine the one-digit data signals of HEN2. When any digits are “p” or “n” (non-zero digits), the next digit becomes “o”, thus obtaining “po” or “no”. On the other hand, when any digits are “o”, the range of analog signals corresponding thereto is equally divided into four sections. With the two end quarter sections, the corresponding digits of digital data signals are made respectively as “p” and “n”, while with the two intermediate quarter sections are made to “o”. Repetition of this process from higher order digits to lower order digits can determine the region of analog signals corresponding to individual values of digital data signals of HEN2 having a pre-determined number of digits. And then, between the above digital data signals and analog signals, at least one way or mutual conversions are made.
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Norman S. Scott, “Computer Number Systems and Arithmetic” 1985, Title Page, Chapter 7, pp. 198-201.
Flynn ,Thiel, Boutell & Tanis, P.C.
Jean-Pierre Peguy
Kokochi Sangyo Co., Ltd.
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