Abstract: In a magnetooptical recording method and apparatus the intensity of a laser beam to be radiated onto an over-write capable magnetooptical disk is raised from P.sub.L to an intensity P.sub.H higher than P.sub.L, the intensity is reduced to an intensity P.sub.LT lower than P.sub.H after P.sub.H is maintained for a time T.sub.W1, the laser beam is intensity-modulated at a period T.sub.p between P.sub.LT and an intensity P.sub.W2 higher than P.sub.LT so as to form a mark on the magnetooptical disk by a high-temperature cycle, thereafter, the intensity is reduced to an intensity P.sub.LB lower than P.sub.L, and the intensity is raised to P.sub.L after an elapse of a time T.sub.off. The intensity P.sub.L is selected from an intensity range defined between an upper limit and a lower limit. The upper limit is a laser beam intensity for maintaining a pre-heat state in which a temperature on the magnetooptical disk becomes a predetermined temperature .THETA..sub.

Abstract: There are provided an error correction circuit for correcting a code error of a compressed information code train having been reproduced from a recording medium, compressed in information amount by compression encoding, and added with an error correction code, by using the error correction code, an expansion circuit for subjecting the compressed information code train outputted from the error correction circuit to decoding corresponding to the compression encoding, and expanding the information amount of the decoded code train, an error concealment circuit for concealing an information code of the information code train outputted from the expansion circuit, by using correlation of the information, the information code being unable to be corrected, and a compression circuit for compression encoding again an information code train outputted from the error concealment circuit.

Abstract: A half-bridge inverter is powered from a constant DC voltage and provides an AC output voltage that is--in contrast with the usual squarewave voltage--describable as being a sinusoidal waveform with the tops clipped off at some fixed magnitude; or, described differently, a waveform composed of truncated sinusoidal waves; or, described still differently, a waveform having trapezoidally shaped half-cycles. This AC voltage is applied across the primary winding of a so-called reactance transformer, whose loosely coupled secondary winding is connected across a gas discharge lamp. The internal inductive reactance of the secondary winding constitutes a lamp ballasting means by way of limiting the magnitude of the resulting lamp current to a pre-established desired level.

Abstract: A lighting device using a fluorescent lamp adapted to be powered from a low voltage direct current source. Operation of the lamp is facilitated by the inclusion of a stabilized blocking oscillator circuit which provides high voltage alternating current for ignition and operation of the lamp as well as power for operating the filamentary heaters when included in the lamp. Operation at a very high frequency improves the efficiency of the fluorescent lamp, thus providing greater light output.