Abstract: Device ID detecting means detects an ID of a device on another party. Next, it is checked whether the device ID is included in historical information stored in authentication histories storing means. If the device ID is included in the historical information, authenticating means performs authentication with authenticating means on another party. Thereafter, when an AV data transmission direction is provided from a user to command input means, the command is notified through command control means to AV data transmitting means which starts transmission of AV data.

Abstract: A data communications system and a data communications method enable disappearance of digital AV data arranged into data packet to be prevented. An initialized state detector monitors the state of a transmission line whether or not an initialization protocol of a transmission line occurs. A packet controller arranges the digital AV data into data packet. When the transmission line is under the bus reset condition, it causes output of the digital AV data arranged into data packet to be interrupted due to control of a timing controller. While when the transmission line is not under the bus reset condition, it causes the digital AV data arranged into the data packet to be sent to the transmission line. A reception equipment connected to the transmission line receives the digital AV data arranged into the data packet sent from the transmission equipment before linking.

Abstract: The ultra-directional speaker of the present invention comprises: an audio generator for generating an audio signal; an ultrasonic generator for generating an ultrasonic signal; a frequency modulator for frequency modulating the ultrasonic signal with the audio signal to produce a frequency modulated ultrasonic signal; and an electro-acoustic transducer for transducing the frequency modulated ultrasonic signal into acoustic waves.

Abstract: A super-directional loudspeaker is provided, which makes for a listener to receive an audible sound at a high sound pressure with a compact size. This loudspeaker is comprised of a supporting member having a concave surface, and electro-acoustic transducer elements fixed to the supporting member. The elements are designed to receive an electrical input signal and to produce acoustic vibrations according to the electrical input signal thus received, thereby emitting directional ultrasonic waves in the air. The elements are arranged along the concave surface of the supporting member in such a way that the directional ultrasonic waves emitted by the elements propagate in the air to converge on a listening point in front of the concave surface. It is preferred that the curvature of the concave surface of the supporting member is adjustable according to the location of the listener.

Abstract: An image data encoding system is disclosed, that comprises a discrete cosine transforming means for discrete-cosine transforming the original image, an electronic watermark data embedding means for embedding the electronic watermark data in the data that has been transformed by the discrete cosine transforming means, and a data selecting means for selecting the output signal of the discrete cosine transforming means or the output signal of the electronic watermark data embedding means. Another image data encoding system is also disclosed, that comprises an electronic watermark embedding means for embedding electronic watermark data selected from a plurality of types of electronic watermark data to the digital image data, wherein at least one of the plurality of types of electronic watermark data is predetermined electronic watermark data that does not affect the digital image data even if the electronic watermark data is embedded in the digital image data.

Abstract: In a contents data supplying system, the output device controller 10 obtains an ID of the printer 20 from the printer 20. The output device controller 10 then notifies the contents data supplying device 30 of the ID of the printer 20. The contents data supplying device 30 inserts an electronic watermarking information including the ID notified by the output device controller 10 into contents data hoped by a user who owns the printer 20 and the output device controller 10 to be buried therein. The contents data supplying device 30 then supplies the contents data having the electronic watermarking information buried therein to the output device controller 10 as electronically watermarked contents data The contents data hoped by a user will hereunder be called “original contents data” so as to be distinguished from deformed contents data, and the like.

Abstract: An image data encoding system is disclosed, that comprises a discrete cosine transforming means for discrete-cosine transforming the original image, an electronic watermark data embedding means for embedding the electronic watermark data in the data that has been transformed by the discrete cosine transforming means, and a data selecting means for selecting the output signal of the discrete cosine transforming means or the output signal of the electronic watermark data embedding means.

Abstract: An image data encoding system has a discrete cosine transformer for discrete cosine transforming the original image, an electronic watermark data embedding circuit for embedding the electronic watermark data in the data that has been transformed by the discrete cosine transformer, and a data selector for selecting the output signal of the discrete cosine transformer or the output signal of the electronic watermark data embedding circuit. Another image data encoding system has an electronic watermark embedding circuit for embedding electronic watermark data selected from a plurality of types of electronic watermark data to the digital image data, wherein at least one of the plurality of types of electronic watermark data is predetermined electronic watermark data that does not affect the digital image data even if the electronic watermark data is embedded in the digital image data.