Abstract: A record carrier on which information may be optically recorded and/or read, having a disc-shaped substrate with a spiral or concentric pattern of preformed tracks thereon and a radiation-sensitive layer extending over such track pattern. The tracks are in the form of ridges of substantially constant width and having a periodic radial wobble of a substantially constant mean frequency, which frequency is modulated by a position-information signal identifying the relative positions of the tracks in the track pattern. Apparatus for forming such a track pattern includes means for modulating the radial track wobble in accordance with the position-information signal.

Abstract: A method and apparatus for successively recording a first and a second information signal on a record carrier track which is pre-recorded with track position-code signals alternating with track position-synchronizing signals. Each information signal is converted into a respective modulated digital signal having successive subcode frames, each subcode frame including subcode synchronizing signals and successive information frames which include time code signals. Upon completion of recording of the information in the first modulated signal, recording of succeeding information frames thereof is continued for a predetermined time interval thereafter so that recording of such signal terminates at a boundary position located between successive subcode synchronizing signals on the track. Generation of the second modulated signal is initiated the aforesaid time interval prior to recording, so that recording thereof begins at the boundary position of the first modulated signal.

Abstract: A recording system includes a record carrier of an inscribable type and a recording apparatus. The record carrier is preconditioned with a control information pattern which includes identification of one or more types of information for which recording is permitted on such record carrier. The recording apparatus includes means for determining the type of information received for recording, means for reading the control information represented by the control information pattern on the record carrier, and control means for inhibiting recording if the received information is not of a type identified by the control information read from the record carrier.

Abstract: An optical disc record carrier having a radiation-sensitive surface and a spiral or concentric pattern of information tracks thereon. The radial displacement of each track is modulated to produce a periodic radial wobble, the frequency of such periodic displacement being modulated by a position-information signal identifying the relative positions of the tracks. During recording or reading of information on the tracks the track modulation is read by a scanning beam. A clock signal for controlling scanning velocity is recovered from the track displacement modulation, and an FM demodulator recovers the position-information signal from the frequency modulation of such displacement.

Abstract: An optical recording system wherein the record carrier is pre-recorded with adjustment information indicative of the waveform of the write signal (V.sub.s) to be employed for recording an information signal (V.sub.i) thereon. The recording apparatus includes a read/write head for reading the adjustment information before recording, and a control circuit for deriving the write signal (V.sub.s) from the information signal (V.sub.i). The control circuit includes an adjustment circuit which selects a write signal waveform in conformity with the adjustment information read from the record carrier.

Abstract: A record carrier (1) in the form of a disc-shaped carrier provided with a radiation-sensitive layer (6) having a servo track (4). The servo track produces track modulation by having a radial wobble, or lateral periodic deviation whose frequency is modulated with a position-information signal (FIG. 2). Apparatus (FIG. 8) is presented which forms the track pattern during manufacture of the record carrier (1). When an information signal (Vi) is recorded on the record carrier (1) and the recorded signal is read by recording and/or read apparatus (FIG. 4), the position-information signal (FIG. 2) is recovered by an FM demodulator device (60) from variations in the scanning beam (55) which are propduced by the track modulation. Moveover, a clock signal for the purpose of scanning-velocity control is recovered from this variation in the scanning beam. Furthermore, embodiments of the record carrier highly suitable for recording EFM-modulated signals are described.