Browse Prior Art Database

Data Coding and Device for Reading Corresponding Codes

IP.com Disclosure Number: IPCOM000076622D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 46K

Publishing Venue

IBM

Related People

Arosenius, L: AUTHOR

Abstract

The figures show a delta distance code and a device for reading delta distance code. Delta code 10 is inherently self-clocking and, is therefore, very useful for information retrieved by, e.g. handscanning. The information in delta code 10 is carried by time intervals represented by markings on a paper, magnetization on magnetic media or ripples on a surface. If two adjacent intervals are equal, within a set tolerance limit, a binary one is represented, if the intervals are unequal a binary zero is represented.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Data Coding and Device for Reading Corresponding Codes

The figures show a delta distance code and a device for reading delta distance code. Delta code 10 is inherently self-clocking and, is therefore, very useful for information retrieved by, e.g. handscanning. The information in delta code 10 is carried by time intervals represented by markings on a paper, magnetization on magnetic media or ripples on a surface. If two adjacent intervals are equal, within a set tolerance limit, a binary one is represented, if the intervals are unequal a binary zero is represented.

The scanning pen 11 picks up the signals from medium 12, and signal adapter 13 converts these signals to a sequence of short pulses, which indicates the beginning, and the end of the intervals. The decoder 14 transforms these intervals into binary 1's and 0's which are stored in a data register 15. In order to allow for widely varying scanning speeds, the decoder must be insensitive to the absolute length of the time intervals, and only register the relative length of adjacent time intervals.

The pulses from adapter 13 are applied to a flip-flop 16. If flip-flop 16 is in the 1 state, pulses from local oscillator 17 are fed over AND gate 18 into a first binary counter 19. If the flip-flop is in the 0 state, the oscillator pulses are fed over AND gate 20 into a second binary counter 21. Thus the counters will alternatively receive from oscillator 17 a number of pulses, which is proportional to the length of the time intervals between the input pulses.

Each counter is equipped with a digital-to-analog converted, DAC R1 and R2, respectively. The first counter 19 has its DAC R1 connected to a positive voltage +V1 and the second counter has its DAC R2 connected to a negative voltage - V2. The resistors are coupled together at point A, and the signal at this point is fed to a differentia...