Abstract: A method of adjusting a frequency response in a ladder-type electric filter having a pair of parallel resonators and a pair of strip-shaped series resonators arranged in a predetermined manner to form a fundamental filter circuit in which at least one of corner portions of each of the strip-shaped series resonators is beveled without changing its length L to regulate its resonance frequency so that the device can be stored within a case without displacing it from its proper position and held in contact with a contact at its node of vibration.

Abstract: A piezoelectric filter device having one or more pairs of piezoelectric resonators for forming a ladder-type filter circuit, a plurality of terminal plates including an input and output terminal plates for electro-mechanically holding respective resonators at oscillation nodes, and a casing for containing the piezoelectric resonators and the terminal plates and having an opening which is closed by an insulating filler, in which the opening has an inner peripheral rough surface with which the insulating filler is securly bonded. The casing has a connecting extention extending from the bottom wall thereof which is longer than cranked or bent connecting legs of the input and output terminal plates. Alternatively, each cranked or bent connecting leg has a width larger than that of its tip portion to be connected to a printed-circuit board.

Abstract: A ladder-type electric filter device in which a casing is partitioned into two compartments, one for containing strip-shaped series piezoelectric resonator elements which are operated at a longitudinal oscillation mode and the other for containing square shaped parallel piezoelectric resonator elements which are operated at a peripheral oscillation mode, each of the series and parallel resonator elements is layered along the height of the casing. Alternatively, an input, output and grounding terminal plates for electrically connecting rectangular piezoelectric resonator elements operated at a longitudinal oscillation mode are integrally formed with a casing for containing the rectangular piezoelectric resonator elements.

Abstract: A capacitor which includes a dielectric layer, a metal electrode and a capacity adjusting electrode erodable by exposure to light energy, the capacity adjusting electrode being a film made of at least one selected from metallic oxides, metallic nitride and metallic boride.

Abstract: A ladder-type piezoelectric filter having a plurality of piezoelectric resonator elements connected to a series branch and a plurality of piezoelectric resonator elements connected to a parallel branch wherein each of the series and parallel piezoelectric resonator elements positioned on the input and output terminal sides, respectively, has a Qm value larger than that of the remaining series and parallel piezoelectric resonator elements, thereby improving a group delay frequency characteristic while suppressing any increment of an insertion loss.

Abstract: A recording system and a recording and/or reproducing apparatus in which a first information unit signal is recorded on a recording medium; a first data unit signal relating to the first information unit signal is recorded on the recording medium at the rear side of the first information unit signal; when a succeeding second information unit signal newly appears thereafter, second information unit signal is recorded on the recording medium at the rear side of the first information unit signal; and a second data unit signal relating to the second information unit signal and the first data unit signal are recorded together on the recording medium at the rear side of the second information unit signal.

Abstract: A ladder-type electric filter circuit apparatus having a plurality of thinner electric filter units wherein each electric filter unit includes a casing of metal into which piezoelectric resonator elements and terminal plates are inserted, and the metal casing is securely mounted on a printed circuit board by soldering. The piezoelectric resonator elements and terminal plates are insulated from the metal casing by an insulating plate and an elastic insulatiang plate which is also served as a vibration or shock absorber for protecting the contained filter from any external vibration or shock propagated through the printed circuit board.