US3877069A — Skew correction system

Claim 1

Independent Claim 252 words

An electronic skew correction system, comprising in combination; recording means and playback means, said recording means having a capability of receiving and storing information in a multiplicity of information channels and said playback means having an ability for reproducing said stored information, information storage means, said information storage means being operatively connected to said recording and playback means for storage of information on a multiplicity of information channels, synchronizing means, operatively connected to said recording and playback means, synchronizing signal generating means, said synchronizing signal generating means being operatively connected to said recording means whereby said synchronizing signal generating means generates synchronizing signals for storage upon said information storage means, and phase shift control means, said phase shift control means being operatively to said playback means for control of the information reproduced from the information stored on said storage means whereby said phase shift control means vary the various channel phase relations of the information reproduced, and wherein said synchronizing generator means includes, a sine wave oscillator, and phase shift means, said sine wave oscillator being connected to generate a reference sine wave signal for recording onto one of the external information channels of said tape information storage means, and said phase shift means being operatively connected to said reference signal generating means for shifting the phase of said reference signal for the production of equal amplitude signals ninety degrees out of phase with said reference signal for recording on another one of the external channels of said information storage recording means.

Claim 2

Dependent Claim 252 words

An electronic skew correction system, comprising in combination; recording means and playback means, said recording means having a capability of receiving and storing information in a multiplicity of information channels and said playback means having an ability for reproducing said stored information, information storage means, said information storage means being operatively connected to said recording and playback means for storage of information on a multiplicity of information channels, synchronizing means, operatively connected to said recording and playback means, synchronizing signal generating means, said synchronizing signal generating means being operatively connected to said recording means whereby said synchronizing signal generating means generates synchronizing signals for storage upon said information storage means, and phase shift control means, said phase shift control means being operatively to said playback means for control of the information reproduced from the information stored on said storage means whereby said phase shift control means vary the various channel phase relations of the information reproduced, and wherein said synchronizing generator means includes, a sine wave oscillator, and phase shift means, said sine wave oscillator being connected to generate a reference sine wave signal for recording onto one of the external information channels of said tape information storage means, and said phase shift means being operatively connected to said reference signal generating means for shifting the phase of said reference signal for the production of equal amplitude signals ninety degrees out of phase with said reference signal for recording on another one of the external channels of said information storage recording means.

Claim 3

Dependent Claim 181 words

The combination of claim 1 wherein said phase-shift control means comprises; error signal detection means, said error signal detection means being operatively connected to said playback means for detection of the phase error between said ninety degree phase-shifted reference signal and said reference signal recorded on the external channels of said information recording medium, thereby providing an error correction signal proportional to said phase error, voltage divider means, said voltage divider means being operatively connected to the output of said error detector means for dividing said error signal into amplitudes proportional to the position of the channel recorded on said information storage means, feedback means, said feedback means being operatively connected to the output of said error detector means for control of said error correction signal, and control means, said control means being operatively connected to said voltage divider means and operatively connected to the outputs of each information channel recorded upon said information storage means, whereby the output signal from said error detector means controls the phase shift of said control means for control of the information channel phase relations.

Claim 4

Dependent Claim 208 words

The combination of claim 2 wherein said feedback error detecting means comprises; a fixed delay line and an electrically variable delay line, each of said delay lines being respectively connected to the output of said external synchronizing signal recording channels, phase detector means, said phase detector means being operatively connected to the outputs of said fixed delay line and said electrically variable delay line for detection of phase difference between said signals, integrating means, said integrating means being operatively connected to the output of said phase detection means for integration of signals generated therein, amplifier-modulation and demodulation means, said amplifiermodulation and demodulation means being operatively connected to the output of said integration means for production of an error signal representing the phase difference between said synchronizing signals recorded on the external channels of said information storage means, error summing means, said error summing means being connected to the output of said amplifier-modulator and demodulation means for summing the errors detected between said externally recorded synchronizing signal channels, the output of the error summer being applied both to said electrically variable delay line and to said voltage divider means whereby the output from said voltage divider means controls said control means in accordance with the detected error correction signal.

Claim 5

Dependent Claim 20 words

The combination of claim 3 wherein said control means comprises one electrically variable delay line for each recorded information channel.

Claim 6

Dependent Claim 80 words

The combination of claim 4 wherein said amplifier-modulation and demodulation means comprise; means for generating a reference carrier signal, chopper means, coupled to said means for generating a reference carrier signal, for modulating said integrated signals by said reference carrier signal, said chopper means being connected to the output of said integrator means, amplifier means for amplifying said modulated signals, and means for demodulating said amplifier signals, said demodulating means being operatively connected to the output of said amplifier means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-04-07	1978-10-07	1979-04-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-04-07	1982-10-07	1983-04-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-04-07	1986-10-07	1987-04-08	$7700.00	Window Closed / Lapsed

Skew correction system

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