Abstract: An electronic ballast for hot cathode discharge lamp comprises a DC voltage source, a chopper, and an inverter. The chopper includes a switching element connected in series with an inductor across the DC voltage and driven to turn on and off for providing a periodically interrupted voltage which is smoothed by a capacitor to produce a smoothed DC voltage as a chopper output. The inverter includes at least one switching element which is coupled to the chopper output to produce therefrom a high frequency AC voltage as an inverter output to be applied to cathodes of the discharge lamp for lighting the discharge lamp. The ballast is characterized to include an inverter controller and a delay circuit. The inverter controller controls the inverter to operate selectively in a normal mode of providing the inverter output of a first level and in a limited mode of providing the inverter output of a second level which is lower than the first level and is determined to give a preheating current to the cathodes.

Abstract: An electrodeless low-pressure discharge lamp includes a translucent discharge-vessel of a glass that contains at least 5 weight % sodium, encloses a discharge-space and includes a mercury containing fill. The lamp further includes a device to maintain an electrical discharge in the discharge space and an auxiliary radiation source that emits at least 0.5 mW of visible radiation when activated, to provide a relatively short ignition time.

Abstract: A multilayer duplexer package is provided, which includes: two surface-acoustic-wave filter chips having different center pass band frequencies; and at least two phase matching circuits for matching the phase of one filter chip to that of the other filter chip, said phase matching circuits respectively comprising strip lines stacked one above another, and said strip lines each having a characteristic impedance higher than the characteristic impedance of an external circuit to be connected to the duplexer package.

Abstract: A SAW filter includes a first SAW resonator having a pair of terminals and a predetermined resonance frequency (f.sub.rp), the first SAW resonator being provided in a parallel arm of the SAW filter. A second SAW resonator has a pair of terminals and a predetermined resonance frequency (f.sub.rs) approximately equal to a predetermined antiresonance frequency of the first SAW resonator (f.sub.ap). The second SAW resonator is provided in a series arm of the SAW filter. An inductance element is connected in series to the first SAW resonator.

Abstract: In a SAW filter, first and second geometrically parallel two-port SAW resonators, each operable in triple longitudinal modes having first through third resonance peaks in a descending frequency order, are electrically parallel connected on a piezoelectric substrate to have lower and higher frequency passbands with the first and the second resonance peaks of the lower frequency passband brought into substantial coincidence in frequency with the second and the third resonance peaks of the higher frequency passband.

Abstract: A ballast for operating gas discharge lamps has a voltage boost, a half-bridge inverter and a parallel resonant circuit. An inverter control inhibits operation of the inverter when power is initially applied to the ballast.

Abstract: A distributed impedance circuit MR coil design comprised of a transmission line tunable cavity resonator which is well suited for but not limited to use at high frequencies and for large volumes such as in high field (e.g. 4.1 tesla) clinical MR applications. The distributed circuit transmission line resonator is designed for high frequency, large conductive volume applications where conventional lumped element coil designs fail. A resonant coaxial cavity is variably tuned to the Larmor frequency of interest by tunable transmission line elements. The resonator is effective for large head and body sized volumes, high efficiencies, and broad tuning ranges to frequencies of 500 MHz. The B.sub.1 homogeneity of the resonator is a function of the electromagnetic properties of the load itself. Maxwell's equations for the fully time-dependent B.sub.1 field predicts "coil" homogeneity with finite-element models of anatomic structure.

Abstract: A high-frequency apparatus usable as a branching filter, branching filter module and/or a radio communication apparatus. The high-frequency apparatus includes a conductor substrate, a first dielectric layer provided on the conductor substrate, a strip conductor provided on the first dielectric layer, and a second dielectric layer provided on the strip conductor and having through holes provided therein. At least one elastic surface-wave element is provided over the second dielectric layer in a position above the strip conductor and is connected to the strip conductor by the through holes.

Abstract: An illumination system with a panel that is capable of producing electroluminescence as well as reflecting incident light independent of the electroluminescence function of the panel. A layer of phosphor is excited by a power source, and a reflective layer disposed on top of the phosphor layer reflects incident light from an outside light source. The reflective layer is transparent and does not interfere with the electroluminescence of the panel.

Abstract: A coaxial-to-microstrip transition compensated to reduce the impedance discontinuity and parasitic inductance of the transition. The impedance discontinuity is reduced by decreasing the inductance due to the center conductor pin of the coaxial line and the inductance due to the bond wire connecting the center conductor pin to the microstrip line. The impedance discontinuity is also reduced by increasing the capacitance from the microstrip line to ground and from the microstrip line to the center conductor pin of the coaxial line. To reduce the inductance in the signal conduction path, a small diameter center conductor pin is used. A short length of bond wire, doubled around the center conductor is used to connect the center conductor pin to the microstrip line. Also, a thin dielectric substrate is used to minimize the length of the center conductor pin that extends beyond the base of the coaxial housing.

Abstract: An apparatus and a method for controlling an illumination of a lamp.

Abstract: An incandescent bulb for use in a submerged swimming pool light fixture is disclosed, which includes a filament, at least one spring-biased filament support, and a grounding device. The filament support includes an exposed current-conducting portion and is moveable in response to the spring bias. The current-conducting portion of the filament support is arranged to allow it to come into electrical contact with the grounding device when the filament support moves in response to the bias of the spring. The filament is disposed to prevent movement of the filament support when the filament is intact and the lamp is in normal operating condition.

Abstract: A surface acoustic wave filter according to the present invention is constructed by connecting in series one or two or more filter functional units each comprising a first surface acoustic wave resonator having input and output terminals connected in series with a signal line and a second surface acoustic wave resonator having input and output terminals one of which is connected to the signal line and the other of which is grounded. The first surface acoustic wave resonator is constituted by one interdigital transducer and a pair of electrically open strip type grating reflectors with the interdigital transducer interposed therebetween, and the second surface acoustic wave resonator is constituted by one interdigital transducer and a pair of electrically short strip type grating reflectors with the interdigital transducer interposed therebetween.

Abstract: A piezoelectric component includes an input terminal plate, a series ceramic resonator, an output terminal plate, a parallel ceramic resonator and a ground terminal plate stacked between a first case and a second case. Lead portions of the input terminal plate, the output terminal plate and the ground terminal plate are outwardly projected from the cases. These terminal plates and the ceramic resonators are in pressure contact with each other to attain electrical conduction therebetween and thus, form a single-section ladder type filter.

Abstract: A circuit for an intermediate frequency filter combines a variable bandwidth series resonant filter circuit and a parallel resonant filter circuit. A variable output impedance drives the filter and a variable input impedance amplifier buffers the output of the filter. The output impedance of the driver is made to track the input impedance of the output buffer. Changes in the gain of the filter with respect to bandwidth are relatively small. The noise figure of the filter remains low. The circuit is not operated in the non-linear region of the crystal because relatively low drive currents are needed at narrow bandwidths so that the crystal is not overdriven. The LC filter tunes out the stray capacitance from the load of the crystal filter.

Abstract: A micromechanical filter having planar components, and manufacturable using very large scale integrated circuit microfabrication techniques. The input and output transducers are interdigitated comb electrodes. The mechanical coupling between the input and output transducers includes planar flexures, displacement of the electrodes producing bending of the elements of the flexures. By sealing micromechanical filters in a vacuum and providing on-board circuitry, high signal-to-noise ratios and quality factors are achievable. Construction of a real-time spectrum analyzer using many micromechanical resonators, provides a device with high accuracy and a short sample time.

Abstract: Acoustic frequency mixing devices for controlling high frequency signals by the generation of acoustic waves are disclosed. The devices include (a) a crystalline substrate of MTiOXO.sub.4 (wherein M is K, Rb, Tl and/or NH.sub.4 and X is P and/or As) having a surface with at least two input areas; and (b) an input interdigital transducer deposited on each of at least two signal input areas of said substrate surface, each IDT suitable for connection to a source of electric signal and for inverse piezoelectrically generating acoustic waves (e.g., SAWs or B-G waves) in the substrate. For controlling high frequency electrical signals, the substrate surface has a output area and the device typically includes an output electrode (e.g.

Abstract: An integrated and drop-in EMI filter that features common-mode and differential-mode noise filtering capabilities is disclosed. The common-mode portion and the differential-mode portion of the filter are independent of each other in that the two filter portions may be made out of different ferrites, also in that, the an increase in the filtering capability in one mode, such as having an increased number of turns in the winding, would not affect or reduce the filtering capability of the other mode, such as reducing the overall throughhole depths a conductor travels.

Abstract: An electromagnetic compatibility (EMC) filter used in a hybrid technology circuit component, having current-carrying lines and a ground conductor, for protection against electromagnetic interference. The current-carrying lines and ground conductor are arranged on a ceramic plate. The current-carrying lines are covered by a dielectric, which in turn, is covered by an upper metal screen in electrical contact with the ground conductor. A lower metal screen is arranged on the ceramic plate beneath the current-carrying lines and is in electrical contact with the ground conductor.

Abstract: A control apparatus for a fluorescent lamp for detecting an end-of-life state of a fluorescent lamp for making it possible to take suitable countermeasures. In the control apparatus, a load circuit is formed of a capacitor connected between filaments of a fluorescent lamp and a choke coil connected in series with the filament, and there are provided a detection coil for detecting a tube current flowing through the load circuit and a detection circuit receiving an output voltage of a rectifier circuit rectifying the output of the detection coil for detecting a rise in the output voltage occurring when the output frequency of an oscillation circuit is modulated by a modulation circuit.