Abstract: In an optical disc 7 and an optical disc recording apparatus wherein a desirable information signal is recorded in a recording area of the optical disc 7 in which data such as musical number, starting time, ending time and so on based on the information signal recorded in the recording area of the lead-in area AR.sub.RI, in addition to the recording area of the optical disc 7, extended recording areas AR.sub.EXI and AR.sub.EXO are provided at inner and/or outer peripheral sides outside of the recording area and desirable recording informations are recorded in the extended recording areas AR.sub.EXO and AR.sub.EXO .

Abstract: A cathode-ray tube has an electron gun disposed in its neck in confronting relationship to a phosphor screen through a deflection yoke mounted on the funnel. The electron gun has a cathode assembly for emitting three electron beams, and a main lens for passing the electron beams therethrough. The main lens includes a quadruple lens system responsive to focusing voltages for canceling an astigmatic effect produced on the electron beams when the electron beams are deflected by the deflection yoke, at a peripheral edge of the phosphor screen.

Abstract: In the velocity modulation apparatus for a three-tube projection television, an effective velocity modulation can be implemented under due consideration of humans eye's relative visibility characteristics with respect to the three primary colors of R, G and B, and the velocity modulation apparatus includes a VM signal extracting circuit 1 for extracting a velocity modulation (VM) signal from the luminance signal; a plurality of driving circuits 3 to 5 having three different gains at ratios of 0. 3:0. 59:0. 11; and a red color VM coil 7, a green color VM coil 8 and a blue color VM coil 9 provided for three corresponding Braun tubes, respectively and driven by the driving circuits 3 to 5, respectively.

Abstract: An optical recording medium in which a recording layer (4) on which optically readable data are recorded is formed on a rectangular base material (1), a protective layer (5) is formed by roll coating on the recording layer (4) and wherein the base material (1) on which the recording layer (4) and the protective layer (5) have been formed is cut into a predetermined shape. The protective layer (5) provided on the recording layer (4) is formed of a material having a low Young modulus and a lower thermal conductivity as compared with the base material.

Abstract: A superheterodyne receiver comprises a variable frequency oscillator of PLL (phase-locked loop) type for implementing a first local oscillator and a variable frequency oscillator not of PLL type for implementing a second local oscillator. At least the frequency of a first locally generated signal is varied at reception to vary a received frequency, the frequency of the first locally generated signal is set at frequency calibration to a level equal to the frequency of a first intermediate-frequency signal, the second intermediate-frequency signal is frequency-converted by a BFO signal to a signal having a frequency of voice band, and the frequency of a second locally generated signal is calibrated to set the frequency of the frequency-converted signal to a specified level.

Abstract: A bezel which minimizes possible production of powder by rubbing thereof with a cathode ray tube to prevent possible deterioration of an appearance of a display unit in which the bezel and the cathode ray tube are assembled. The bezel has, around a substantially rectangular opening thereof, a contact area at which it is to contact with a cathode ray tube to which the bezel is to be assembled. The contact area is provided by a plurality of ribs formed in a suitably spaced relationship from each other on the bezel along an inner periphery of the opening in such a manner as to extend perpendicularly to the inner periphery of the opening. Some of the ribs which are provided along a pair or two pairs of opposing edges of the inner periphery of the opening may be replaced by different ribs which individually extend in parallel to the edges of the inner periphery of the opening.

Abstract: A display apparatus for displaying a video image operates with plural horizontal scanning frequencies. The apparatus includes a horizontal scanning frequency oscillator for generating a signal in synchronism with a horizontal synchronous signal of an input video signal; and a control unit for controlling a frequency of an output of the horizontal scanning frequency oscillator corresponding to the horizontal synchronous signal of the input video signal. A multi-scan video monitor may be provided for displaying the image relative to any of the plural horizontal scanning frequencies without any turbulence.

Abstract: A circularly polarized generator for transmitting circularly polarized transmitted electromagnetic waves and a circularly polarized wave reception antenna for receiving the electromagnetic waves is disclosed. A crank-shaped conductor pattern composed of a pair of U-shaped portions connected to each other so that the open sides of the letter U are directed oppositely to each other is affixed on a substrate, and has its one end arranged as a signal transmitting and receiving end for achieving minimum transmission losses and optimum axial ratio or intersecting polarized wave component discriminating factor as well as for reducing the size and weight and assuring ease of manufacture.

Abstract: A maximum likelihood decoder (28) comprises a Viterbi decoding unit (30) and a symbol concluding unit (29). Final N-M bit data of data of N (>M) bit unit, to which M-bit original data is converted, is supplied to the symbol concluding unit (29) as a terminal portion and other data is supplied to the Viterbi decoding unit (30), thereby being demodulated by a demodulator (37). A maximum likelihood decoding apparatus is provided in which image data or the like can be recorded and reproduced at high speed and maximum likelihood parallel decoding is effected. A reproducing data demodulating apparatus using such maximum likelihood decoding apparatus is also provided.

Abstract: An image developing apparatus using a laser beam source to produce an original plate for producing a master disk of an optical type recording disk such as video disk and the like. A disk base plate 3 formed thereon with an exposed optically sensitive film 2 is rotated while developing solution 6 is supplied on the optical sensitive film 2 to remove the exposed parts of the film. To monitor the development, a laser beam 8 from a laser beam source 7 is irradiated on an exposed portion of the optical sensitive film 2 which is being dissolved and zero and first order diffraction light 9 and 10 are detected by first and second detectors 11 and 12. Light amount control element 13 are provided to maintain constant the detected level of zero order light by controlling the laser, and the first order light is used to detect a stop time for the development. Stabilization of the zero order light eliminates fluctuations from external sources such as dust, mist etc.

Abstract: A tape cassette includes supply reel and a takeup reel each with a plurality of notches arranged along the entire outer circumference of the lower flange of the reel. A plurality of projections are provided on a lower housing of the cassette for engaging the plurality of notches, and a resilient member is provided in an upper housing of the cassette for biasing the supply reel and the takeup reel toward the lower housing, causing the notches to engage the projections to form a lock for preventing rotation of the reels when the tape cassette is not in use.