Teac Corporation

Mitsubishi Electric Corporation

Tetsuro Araki

Hiroyuki Onda

Mitsumasa Kubo

Kazuhiko Nakane

Akira Mashimo

Masaharu Ogawa

Hiroshi Tsuyuguchi

Teruo Furukawa

Yoshiaki Sakai

Katsuya Enami

Yoshiaki Umeda

A disk apparatus comprising a controller receiving commands from a command input device and controlling an entire operation of the disk apparatus. The rotating control function is coupled to the controller for controlling the first motor. The pickupmotor control function is coupled to the controller for controlling the second motor. The pickup control function is coupled to the controller for controlling a focusing operation and a tracking operation of the pickup. And the signal processing function is coupled to the controller for processing a recording signal to be recorded on the disk-shaped recording medium and a reproduced signal read out therefrom. The controller is comprised function-stop function for determining whether or not any command is received from the command input device during a predetermined period of time in a state. The disk apparatus is maintained in a predetermined mode and for stopping predetermined function among the rotating control function, the pickup motor control function, the pickup control function, and the signal processing function when it is determined that no command is received from the command input device during the predetermined period.

Disk apparatus having a power consumption reducing mechanism

A method and apparatus well suited for the conversion of a digitized audio signal into analog form with as wide a dynamic range as possible. A digital dither signal is added to a digital audio or like data signal to provide a digital data/dither signal. This digital data/dither signal and the digital dither signal are both converted into an analog data/dither signal and an analog dither signal respectively, and the analog dither signal is subtracted from the analog data/dither signal to obtain an analog data signal equivalent to the digital data signal. The level of the incoming digital data signal may be so high that when the digital dither signal is added thereto, the total level of the data/dither signal may exceed the capacity of the digital to analog converter in use. In that case the digital dither signal is either gated off or reduced in level, with the result that the digital to analog converter inputs either the data signal only or the data/dither signal having a total level not exceeding its capacity.

Wide dynamic range digital to analog conversion method and system

Wide dynamic range digital to analog conversion method and systems

A method and apparatus well suited for digitizing an audio signal with as wide a dynamic range as possible. An analog dither signal is added to an analog audio or like data signal to provide an analog data/dither signal. This analog data/dither signal and the analog dither signal are both converted into a digital data/dither signal and a digital dither signal respectively, and the digital dither signal is subsequently subtracted from the digital data/dither signal to obtain a digital data signal equivalent to the analog data signal. The magnitude of the incoming analog data signal may be so high that when the analog dither signal is added thereto, the magnitude of the resulting data/dither signal may exceed the capacity of the analog to digital converter in use. In that case the analog dither signal is either gated off or reduced in magnitude, with the result that the analog to digital converter inputs either the data signal only or the data/dither signal having a magnitude not exceeding its capacity.

Wide dynamic range analog to digital conversion method and system

For the distortionless conversion of an audio or like data signal from analog to digital form as by pulse code modulation, the input data signal is time division multiplexed with an analog dither (white noise) signal to provide a multiplex signal composed of the analog dither signal and an analog data/dither signal, the latter being an addition of the analog data and dither signals. Then the multiplex signal is converted from analog to digital form by one and the same analog to digital converter. The subsequent removal of the digital dither component from the digital data/dither signal provides a digital data signal as a replica of the input analog data signal. The use of the same converter for the conversion of both dither signal and data/dither signal from analog to digital form makes possible the maximum possible removal of the dither from the digital data/dither signal.

Analog to digital conversion method and system with the introduction and

A digital data signal such as a digitized audio signal is time division multiplexed with a digital dither signal to provide a multiplex signal compound of the digital dither signal and a digital data/dither signal, the latter being an addition of the digital data and dither signals. Then the multiplex signal is converted from digital to analog form by one and the same digital to analog converter. The subsequent removal of the analog dither signal from the analog data/dither signal provides an analog data signal as a replica of the digital data signal. The use of the same converter for the conversion of both dither signal and data/dither signal from digital to analog form makes possible the maximum possible removal of the dither from the analog data/dither signal.

Digital to analog conversion method and system with the introduction and

A system for converting an audio or like data signal from digital to analog form, with the addition of dither (white noise) to the digital input, with or without the subsequent removal of the dither from the analog output, for the reduction of quantization noise. Included is a network of n adders, equal in number to the n bits of the coded data signal, for adding in bit parallel form the digital data signal and the digital dither signal. Generated by an analog dither generator, the dither signal is transformed by an analog to digital converter into an m bit coded digital output, m being less than n, prior to delivery to the adder network. Some, preferably all, of the m bits of the digital dither signal are each added to, for example, two different ones of the n bits of the digital data signal so that, for instance, an eight bits analog to digital converter can be used for the provision of a digital dither signal to be added to a 16 bits digital audio signal. The adder network is connected to a digital to analog converter for converting the bit parallel addition of the data and dither signals into analog form.

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Hachioji, Japan

Tetsuro Araki