Abstract: A method of and apparatus for modifying a video signal such that a video picture can be reproduced on a television receiver in response to the modified video signal, but if the modified video signal is transmitted and then recorded on a video signal recorder, an accurate video picture cannot be reproduced if that recorded modified video signal subsequently is played back. The vertical blanking interval containing one set of equalizing pulses followed by a set of vertical synchronizing pulses followed by another set of equalizing pulses is modified by replacing a portion of the vertical synchronizing pulses and a portion of the set of equalizing pulses following the vertical synchronizing pulses with simulated equalizing pulses in at least some of the vertical blanking intervals. The amplitude and frequency of the simulated equalizing pulses are equal to that of the actual equalizing pulses.In one embodiment, the modified video signal is transmitted via, for example, cable or RF transmission.

Abstract: A system for recording and later reproducing video signals on a magnetic recording medium by producing a modulated signal in which the video information is carried primarily on only one sideband and the carrier, which may be suppressed by certain types of modulation is at a frequency within the band occupied by the video signals prior to modulation. The carrier may originally be at a higher frequency and be converted to the aforementioned frequency, which is also within a frequency band that includes the peak reproduction point in the response characteristic of a magnetic recording and reproducing system. In the case of certain types of modulation the carrier is phase-and frequency-controlled to eliminate interference between signals recorded on adjacent tracks on the magnetic medium.

Abstract: In an apparatus for recording and/or reproducing information signals, such as, video signals, on a magnetic tape or other record medium by means of rotary recording and/or reproducing heads which scan successive parallel tracks extending across the tape as the latter is longitudinally advanced: a servo-control system for ensuring accurate scanning of the tracks during reproducing operation includes an auxiliary rotary head repeatedly traversing the tape in coordination with the recording and/or reproducing heads and which, during the recording operation, records pilot signals in areas that are spaced apart along an edge portion of the tape and also traversed by the recording and/or reproducing heads, with each of such areas having an extent in the longitudinal direction of the tape that corresponds, and is in predetermined positional relation to a respective plurality of the successive tracks in which the information signals are being recorded; and, during reproducing operation of the apparatus, a reproduced