Variable cell width recording
AssigneeMinnesota Mining and Manufacturing Company
InventorJohn L. Rynearson
Life of this patent
Estimating the term…
Abstract
Binary numbers are recorded on a track of a medium in the form of signals of first and second voltage levels, respectively indicating alternate timing signals of uniform time duration t and data signals of variable time duration x. A timing signal is followed by a short data signal to indicate binary zero, by a longer data signal to indicate binary one, and by even longer data signals to indicate the absence of binary data. The signals may be decoded by counting up from zero during each timing signal and down during each data signal such that a positive count-down indicates a binary zero, a relatively small negative count-down indicates a binary one, and a relatively large negative count-down indicates absence of binary data.
Claims15
Method of encoding binary numbers on a recording medium comprising the steps of:
- 1. generating alternate timing and data signals of first and second voltage levels, respectively, wherein each timing signal has a fixed time duration t and the data signals have variable time durations x, a first binary number is designated by x = at, a second binary number is designated by x = abt, and the absence of binary information is designated by x >
- abct, where a is a predetermined small number and each of b and c is a predetermined number appreciably exceeding one, and
- 2. serially recording the alternate timing and data signals along a track of the medium.
Method of encoding and decoding binary numbers on a recording medium comprising the steps of:
- 1. generating alternate timing and data signals of first and second voltage levels, respectively, wherein each timing signal has a fixed time duration t and the data signals have variable time durations x, a first binary number is designated by x = at, a second binary number is designated by x = abt and the absence of binary information is designated by x >
- abct, where a is a predetermined small number and each of b and c is a predetermined number appreciably exceeding one,
- 2. serially recording the alternate timing and data signals along a track of the medium,
- 3. playing back the recorded signals,
- 4. measuring the time interval t' of a played-back timing signal at a rate R.sub.1,
- 5. measuring the time interval x' of the succeeding played-back data signal at a rate R.sub.2 = rR.sub.1, and
- 6. subtracting the x' measurement in step (5) from the t' measurement in step (4) and producing an output signal
- indicative of the first binary number when the difference is greater than a first quantity t = rn where n is a value intermediate at and abt,
- indicative of the second binary number when the difference is less than said first quantity and is greater than a second quantity t - r(abct),
- indicative of the absence of binary information when the difference is less than said second quantity.
Apparatus for encoding binary numbers on a recording medium comprising:
- 1. means for generating alternate timing and data signals of first and second voltage levels, respectively, wherein each timing signal has a fixed time duration t and the data signals have variable time durations x, a first binary number is designated by x = at, a second binary number is designated by x = abt and the absence of binary information is designated by x >
- abct, where a is a predetermined small number and each of b and c is a predetermined number appreciably exceeding one, and
- 2. means for serially recording the alternate timing and data signals along a track.
Apparatus for encoding and decoding binary numbers on a recording medium comprising:
- 1. means for generating alternate timing and data signals of first and second voltage levels, respectively, wherein each timing signal has a fixed time duration t and the data signals have variable time durations x, a first binary number is designated by x = at, a second binary number is designated by x - abt and the absence of binary information is designated by x >
- abct, where a is a predetermined small number and each of b and c is a predetermined number appreciably exceeding one,
- 2. means for serially recording the alternate timing and data signals along a track of the medium,
- 3. means for playing back the recorded signals,
- 4. means for measuring the time interval t' of each played-back timing signal at a rate R.sub.1,
- 5. means for measuring the time interval x' of each played-back data signal at a rate R.sub.2 = rR.sub.1, and
- 6. means for subtracting the output of the x' measuring means (5) from the output of the t' measuring means (4) and for producing an output signal
- indicative of the first binary number when the difference is greater than a first quantity t - rn where n is a value intermediate at and abt,
- indicative of the second binary number when the difference is less than said first quantity and is greater than a second quantity t - r(abct),
- indicative of the absence of binary information when the difference is less than said second quantity.
Dependencies are inferred from the claim text.