Inscribing digital data on a grooved record by pre-distorting the waveforms

Claim 1

A method for generating an electrical driving signal for controlling a cutting lathe to inscribe a modulated spiral groove representing an ordered sequence of digital data on a record disk intended to be read out by a standardized phonograph, cartridge and decoding circuit, comprising the steps of: providing a clocking pulse train; generating at regular intervals determined by said clocking pulse train, a series of identical waveform symbols of predetermined characteristics to represent said digital data; said waveform being such that it may be decoded by determining the amplitude at specific sampling times occurring at said regular intervals to reproduce with precision said ordered sequence of digital data; and passing said series of generated electrical symbols through a transversal equalizer to said cutting lathe, said transversal equalizer having been adjusted to vary the amplitude of portions of said waveforms over a plurality of said regular intervals such that the waveform reproduced from an inscribed record disk by the standardized phonograph cartridge is substantially the same as said generated electrical symbols.

Claim 2

A method for generating an electrical driving signal for controlling a cutting lathe to inscribe a modulated spiral groove representing an ordered sequence of digital data on a record disk intended to be read out by a standardized phonograph, cartridge and decoding circuit, comprising the steps of: providing a clocking pulse train; generating at regular intervals determined by said clocking pulse train, a series of identical waveform symbols of predetermined characteristics to represent said digital data; said waveform being such that it may be decoded by determining the amplitude at specific sampling times occurring at said regular intervals to reproduce with precision said ordered sequence of digital data; and passing said series of generated electrical symbols through a transversal equalizer to said cutting lathe, said transversal equalizer having been adjusted to vary the amplitude of portions of said waveforms over a plurality of said regular intervals such that the waveform reproduced from an inscribed record disk by the standardized phonograph cartridge is substantially the same as said generated electrical symbols.

Claim 5

A method for generating an electrical driving signal for controlling a cutting lathe operating at a first rotational speed to inscribe a modulated spiral groove representing an ordered sequence of digital data on a record disk intended to be read out by a standardized decoding circuit and phonograph operating at a second rotational speed, said second rotational speed being a fixed factor faster than said first rotational speed, comprising the steps of: providing a clocking pulse train; generating at regular intervals, T, determined by said clocking pulse train, a series of identical waveform symbols of predetermined characteristics to represent said digital data; said waveform being such that it may be decoded by determining the amplitude at specific sampling times occurring at regular intervals to reproduce with precision said ordered sequence of digital data; and passing said series of generated electrical symbols through a transversal equalizer to said cutting lathe, said transversal equalizer including a series of delay sections each having a time delay equal to T, and each except the center one having an adjustable attenuator connected to a summing output junction, said adjustable attenuators having been adjusted by: inscribing a modulated spiral groove on a test disk from a pseudo random source of digital data by generating a series of said waveform symbols to represent said pseudo random digital data and controlling said cutting lathe directly from said generated symbols; reproducing the digital data inscribed on said test disk through a standardized phonograph operating at said second rotational speed and passing the reproduced signals through an equalizer formed from a series of delay sections having a delay time equal to T divided by said fixed factor, with each section connected to the adjustable attenuators of the first mentioned equalizer and adjusting the attenuators to make the shape of the output waveform at said summing junction suBstantially the same as said generated electrical symbols.

Claim 6

A method for generating an electrical driving signal for controlling a cutting lathe operating at a first rotational speed to inscribe a modulated spiral groove representing an ordered sequence of digital data on a record disk intended to be read out by a standardized decoding circuit and phonograph operating at a second rotational speed, said second rotational speed being a fixed factor faster than said first rotational speed, comprising the steps of: providing a clocking pulse train; generating at regular intervals, T, determined by said clocking pulse train, a series of identical waveform symbols of predetermined characteristics to represent said digital data; said waveform being such that it may be decoded by determining the amplitude at specific sampling times occurring at regular intervals to reproduce with precision said ordered sequence of digital data; and passing said series of generated electrical symbols through a transversal equalizer to said cutting lathe, said transversal equalizer including a series of delay sections each having a time delay equal to T, and each except the center one having an adjustable attenuator connected to a summing output junction, said adjustable attenuators having been adjusted by: inscribing a modulated spiral groove on a test disk from a pseudo random source of digital data by generating a series of said waveform symbols to represent said pseudo random digital data and controlling said cutting lathe directly from said generated symbols; reproducing the digital data inscribed on said test disk through a standardized phonograph operating at said second rotational speed and passing the reproduced signals through an equalizer formed from a series of delay sections having a delay time equal to T divided by said fixed factor, with each section connected to the adjustable attenuators of the first mentioned equalizer and adjusting the attenuators to make the shape of the output waveform at said summing junction suBstantially the same as said generated electrical symbols.

Claim 8

A method for generating an electrical driving signal for controlling a cutting lathe to inscribe a modulated spiral groove representing an ordered sequence of digital data on a record disk intended to be read out by a standardized phonograph cartridge and decoding circuit, comprising the steps of: providing a clocking pulse train; generating at regular intervals, T, determined by said clocking pulse train, a series of identical waveform symbols of predetermined characteristics to represent said digital data; said waveform being such that it may be decoded by determining the amplitude at specific sampling times occurring at said regular intervals to reproduce with precision said ordered sequence of digital data; and passing said series of generated electrical symbols through a transversal equalizer to said cutting lathe, said transversal equalizer having been adjusted to vary the amplitude of portions of said waveforms over a plurality of said regular intervals, said transversal equalizer being in the form of a series of delay sections, each section having a time delay, T, and each except the center section having an adjustable attenuator connected to a summing output junction; said equalizer having been adjusted by the steps of: inscribing a modulated spiral groove on a test disk from a pseudo random source of digital generating data by controlling said cutting lathe directly with said generated symbols; and reproducing the waveform inscribed on said test disk through a standardized phonograph cartridge and passing the reproduced signals through said adjustable equalizer, each of the attenuators having been adjusted by application of a testing algorithm to the relative amplitudes of portions of the waveform.

Claim 9

A method for generating an electrical driving signal for controlling a cutting lathe to inscribe a modulated spiral groove representing an ordered sequence of digital data on a record disk intended to be read out by a standardized phonograph cartridge and decoding circuit, comprising the steps of: providing a clocking pulse train; generating at regular intervals, T, determined by said clocking pulse train, a series of identical waveform symbols of predetermined characteristics to represent said digital data; said waveform being such that it may be decoded by determining the amplitude at specific sampling times occurring at said regular intervals to reproduce with precision said ordered sequence of digital data; and passing said series of generated electrical symbols through a transversal equalizer to said cutting lathe, said transversal equalizer having been adjusted to vary the amplitude of portions of said waveforms over a plurality of said regular intervals, said transversal equalizer being in the form of a series of delay sections, each section having a time delay, T, and each except the center section having an adjustable attenuator connected to a summing output junction; said equalizer having been adjusted by the steps of: inscribing a modulated spiral groove on a test disk from a pseudo random source of digital generating data by controlling said cutting lathe directly with said generated symbols; and reproducing the waveform inscribed on said test disk through a standardized phonograph cartridge and passing the reproduced signals through said adjustable equalizer, each of the attenuators having been adjusted by application of a testing algorithm to the relative amplitudes of portions of the waveform.