US 4,651,231 A · Timing system for laser disc having digital information

Abstract

A timing system is disclosed for reading symbol sites, analog or digital from a video signal preferable in a recorded laser format. A video signal having analog data events at precise timed intervals is recorded on a first commercial grade video recorder. The tape is replayed through a second commercial grade recorder to an optical lathe. At the time of playback to the optical lathe, a timing signal is derived from a phase lock loop circuit added to the second commercial grade and recorded on the FM band of the video signal, which signal is then etched by the lathe onto a master optical disc. Simultaneously with the recordation of the substantially continuous FM band, selected horizontal scans on each frame are loaded with both timing and reference level data, the timing portion of these selected scans being later used for phase comparison of the signal. An optical disc master results which has a continuous FM band timing track as well as an interleaved timing information contained in the video signal. Replication from the optical master to stamped copies occurs with the stamped copies being distributed to discrete players for data access. At each player, the continuous FM band timing track is used for the master clock. This continuous clock cycles a ramp generator with each clock pulse. Phase synchronization is taken from the selected horizontal scans distributed through each frame by having a phase comparator change the sample level of the cycled ramp. The changed level of the cycled ramp adjusts the phase of the master clock pulse. Precise readout of analog symbol event occurs in precise timed and phase corrected.

Claims8

Dependent claims

A process for placing timing information on a serial track of data in a video format comprising the steps of:

generating a series of video scans including sync pulses and a video portion;
clocking data into at least the video portion of said scans in precise timed intervals;
placing preselected portions of said timing information interleaved into the video portion of said data;
playing said signal onto a video tape recorder to obtain a video tape of said data;
replaying said video tape to an optical lathe to obtain in a laser disc format the serial data;
during said replaying, separating out the clocking information from said data to form a separate timing signal;
placing said separate timing signal onto a band outside of said video portion on said same recording;
recording said timing signal and said preselected portions with the signal on said optical lathe;
playing the laser disc and clocking the data off of said laser disc using the timing signal from the FM band of the video signal;
and
using the preselected portions of said timing signal interleaved with the data to adjust the phase of the clocking of the data to obtain precised timed location of the data sites on the video field of said video signal.

8 more elements

Dependencies are inferred from the claim text.

Timing system for laser disc having digital information

Life of this patent

Timing system for laser disc having digital information

Life of this patent

Abstract

Claims8