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US 4,963,998 AGranted
Apparatus for marking a recorded signal
AssigneeThorn EM plc
InventorBarry G. Maufe
Life of this patent
Estimating the term…
Abstract
This invention relates to apparatus for marking a recorded signal. The apparatus includes means for generating and storing a marking signal comprising at least two codes which are mutually in phase quadrature. The codes are converted to analogue signal and are used to phase-shift modulate the signal to be recorded, the modulating means performing the function of a single side band modulator on the signal to be recorded.
Claims3
Apparatus for marking a recorded signal, said apparatus including:
- means for generating and storing a marking signal comprising at least two codes which are mutually in phase quadrature;
- means for converting said codes from a digital to an analogue signal;
- and modulating means including phase shift means such that the two marking codes can be used to phase-shift modulate the signal to be recorded, said modulating means performing the function of a single side band modulator on the said signal to be recorded.
Dependencies are inferred from the claim text.