Pioneer Electronic Corporation

Pioneer Video Corporation

Kazunaga Ida

Hiroyuki Ishihara

Makio Yamaki

Yukio Matsumoto

Kazuo Watanabe

Kazuhiro Hayashi

Yoshihiro Kawanabe

Fumio Matsushita

Soichi Toyama

Tatsushi Iizuka

Yoshinobu Takamura

Toshiyuki Naoe

Hideyuki Terauchi

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 digital signal processing device for outputting a holding data in an output register from a DSP in synchronism with a second clock pulse having a frequency lower than that of a first clock pulse for conducting arithmetic processing in the DSP. Accordingly, data to be output from the DSP can be directly read by a microcomputer, and contents in a coefficient memory and a delay time memory, for example, can be updated in accordance with the read data. Further, the digital signal processing device can be applied to an audio apparatus such as a loudness controller and a spectrum indicating apparatus.

Digital signal processing device and audio apparatus using the same

An audio signal data processing system includes first and second processing devices for processing audio signal data, the first and second processing device having input and output ports of at least two channels, and a control device for controlling the operation of the first and second processing device. The input audio signal data is supplied to the input port of one channel of each of the first and second processing devices, and output data from the output port of said one channel of said first processing device is supplied to the input port of the other channel of the second processing device, and output audio signl data are obtained at each output port of both channels of the second processing device. With this arrangement, one of the cascade processing and the parallel processing can be selectively performed without using a change-over switch provided outside the system.

Audio signal data processing system

An audio signal data processing system comprises an input device sequentially supplying incoming audio signal data, a data memory control device writing and reading-out the audio signal data into and from a data memory, a delay memory control device sequentially reading-out the audio signal data from the data memory and storing the data into a delay memory and sequentially reading-out the audio signal data from the delay memory and writing the data into the data memory, an arithmetic device multiplying predetermined coefficient data by the audio signal data having been read-out by the delay memory control device and written into the data memory and summing up results of the multiplication. The arithmetic device includes a plurality of multiplication and summing devices multiplying coefficient data by the audio signal data for each of data groups which are obtained by grouping a predetermined number of the audio signal data read-out by the reading device sequentially in the order of reading and subsequently summing up the multiplied values, and a filter device for executing a filter characteristic operation for calculated values respectively obtained by each of the multiplying and summing device, wherein a filter characteristic of the filtering device is made adjustable.

A pulse width distortion correction circuit in which a digital input signal has its leading and trailing edges smoothed, is added to an analog pulse width control signal and compared to a reference voltage to provide a digital output signal with a corrected duty ratio. A duty ratio detection circuit detects the duty ratio of the digital output signal and provides the corresponding pulse width control signal so as to cause the duty ratio to assume a value of 50%.

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Tokyo, Japan

Kazunaga Ida