Pioneer Electronic Corporation

Asahi Kasei Chemicals Corporation

Fumio Matsushita

Satoshi Kumada

Yoshiki Ohta

Minoru Yoshida

Katsuya Shimizu

Keishi Saito

Kazunaga Ida

Yoshinobu Takamura

Hisashi Takaki

Hiroshi Tsubonuma

Katsumi Amano

Disclosed is a photobase generator comprising a compound having a nitrogen atom and a conjugated multiple bond.

Photobase generator and photocurable resin composition

A substituted cyclopentanone represented by the following formula (2): (wherein Rand Rrepresent a substituent having 1 to 8 carbon atoms, may be the same as Rand R, respectively, and may be the same as each other) can be produced by hydrogenating the double bond in a compound represented by the following formula (1): (wherein Rand Rrepresent a substituent having 1 to 8 carbon atoms) in the presence of a transition metal catalyst by using a carboxylic acid or a specific concentration of a carboxylic acid ester as a solvent. This process can produce a substituted cyclopentanone which is useful as a jasmine fragrance, an intermediate thereof or the like, in a simple and inexpensive manner at a high cis-isomer ratio.

Process for production of substituted cyclopentanone

A rear speaker and a front speaker are provided in a room. A microphone is disposed at a listening position between the front and rear speakers for picking up a first sound from the front speakers and a second sound from the rear speaker. Time lags of the first sound and the second sound is obtained from the outputs of the microphone, and the time difference between the time lags is obtained. An antiphase audio signal opposite to a reflected composite signal included in the first sound picked up by the microphone is provided by the sound field correcting circuit. The antiphase audio signal with the same amplitude is delayed based on the time difference and emitted from the rear speaker so as to cancel the reflected composite signal.

Audio system

A speaker system for use in an automobile vehicle, comprises: a pair of front speakers for converting electric signals fed from a two-channel source into sound signals; a band pass filter for extracting a signal component having a frequency substantially satisfying .lambda.=2L when the automobile vehicle has a length L; a phase adjusting circuit for adjusting the phase of an electric signal; and a rear speaker for converting an electric signal fed through the phase adjusting circuit and the band pass filter into a sound signal.

Speaker system for use in an automobile vehicle

A speaker system for use in an automobile vehicle, comprises: pair of side speakers disposed on left and right sides in a front section within the automobile vehicle; a central speaker disposed in a middle position between the two side speakers; a pair of delay circuits connected on two signal lines leading to the side speakers disposed on the left and right sides within the vehicle; an adder connected between the left and right channels to add together the electric signals transmitted from the left and right channels so as to produce a sum signal; and a band pass filter connected on a signal line leading to the central speaker, said band pass filter being constructed and adjusted to eliminate a high frequency signal component. The sum signal fed from the adder is passed through the band pass filter before being applied to the central speaker.

A sound system with a howling-prevention function comprises an all-pass filter having group delay characteristics, which vary with the elapse of time, provided on a line used for the transmission of an audio signal from a microphone. Owing to the provision of such a sound system, any deterioration in the sound quality with respect to high frequencies and a chorus phenomenon is not produced, thereby making it possible to prevent howling without causing inferior sound quality.

Sound system with howling-prevention function

A sound field compensating apparatus is provided in which delay data produced by one of the delay means in a FIR filter, which is realized by the action of a DSP, is commonly used for producing a plurality of reflected sound data of corresponding channels. Accordingly, the maximum delay time of the delay data is lengthened without increasing the number of delay data retrieving actions per sampling period on the delay memory. Hence, an acceptable number of the reflected sound signals can be obtained for each channel.

Sound field compensating apparatus

A phase-locked loop modulation circuit, such as may be used for a data communications purposes, in which undesired level variations are eliminated by employing d.c. coupling entirely. The circuit includes a level converter circuit which converts a logic signal into a signal having substantially equal levels above and below a predetermined voltage, a voltage-controlled oscillator, and a circuit for superposing the signal having substantially equal levels on a control voltage of the voltage-controlled oscillator so that the output of the voltage-controlled oscillator is subjected to angular modulation. In accordance with the invention, the level converter circuit includes a pair of voltage dividing resistors which divide the supply voltage, a pair of series circuit each composed of a resistor and a switch element connected in parallel with each of the series circuits being connected in parallel to a respective one of the pair of voltage dividing resistors, and a gating circuit for complementarily operating the switch elements on and off in accordance with the logic outputs signal.

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Tokyo, Japan

Fumio Matsushita