Victor Company of Japan, Limited

Tomohiro Mouri

Toshiyuki Iida

Yasuhisa Okabe

Yoshiaki Tanaka

A data distribution system has a portable user terminal, which sends a portable terminal ID or memory card ID and electronic money are sent to a store-based terminal () and receives data content, a store-based terminal (), which receives the portable terminal ID or memory card ID and electronic money from the portable user terminal (), and which sends these to a billing center (), along with a content ID and a store-based terminal ID, a billing center () that receives the content ID, the portable terminal ID or memory card ID, the store-based terminal ID, and the electronic money from the store-based terminal (), and a content center (), which receives the content ID, the portable terminal ID or memory card ID, and the store-based terminal ID, and which distributes data content, via the store-based terminal (), to the portable terminal ().

DATA DISTRIBUTION SYSTEM, DATA DISTRIBUTION METHOD, PORTABLE TERMINAL WITH DATA RECEIVING CAPABILITY, PORTABLE TERMINAL WITH DATA TRANSMITTING/RECEIVING CAPABILITY, RECORDING MEDIUM ONTO WHICH DATA CONTENT IS RECORDED, ENCODING APPARATUS, AND DECODING APPARATUS

A multiplexing-resultant surround signal is decoded into multiple-channel signals including at least a first left-channel signal, a first right-channel signal, and a rear-channel signal. Samples of the rear-channel signal are thinned out to generate a thinning-resultant rear-channel signal. The thinning-resultant rear-channel signal is subjected to a given process to convert the thinning-resultant rear-channel signal into a left surround-related signal and a right surround-related signal. The given process is designed to localize sound images at rear positions with respect to a listener when a rear loudspeaker is absent and only front loudspeakers are used. A surround-effect-added left-channel signal is generated on the basis of the first left-channel signal and the left surround-related signal. A surround-effect-added right-channel signal is generated on the basis of the first right-channel signal and the right surround-related signal.

System for processing audio surround signal

A surround signal processing system receives a surround signal and also a program of processing the surround signal. The received surround signal is decoded into multiple-channel signals according to the received program. The multiple-channel signals include a left surround signal and a right surround signal. The multiple-channel signals are converted into two-channel signals according to the received program. The two-channel signals are transmitted to a pair of loudspeakers respectively. During the conversion of the multiple-channel signals into the two-channel signals, the left surround signal and the right surround signal are subjected to filtering processes according to the received program so that the left surround signal and the right surround signal will be converted into filtering-resultant signals. The two-channel signals are generated on the basis of the filtering-resultant signals. The filtering processes are designed to localize sound images at rear positions symmetrical with respect to a listener when a rear loudspeaker is absent and only front loudspeakers are used.

A surround signal processing apparatus for reproducing surround sound through a pair of speakers arranged at front left and right positions with respect to a listener, based on a monaural rear surround signal input. A sound image localization apparatus is used, as well as a signal processing apparatus having a comb filter to render mutually non-correlative, a left-right pair of rear surround signals based on the monaural rear surround sound signal input.

Surround signal processing apparatus

A surround signal processor reproduces multi-channel audio signals with a pair of left and right rear surround signals via a pair of speakers arranged at front left and right positions roughly symmetrically with respect to a listener. The processor has a sound image localizer with convolvers each of whose filter coefficients Hl and Hr are set based on head transfer functions for each channel of the rear surround signals as follows: Hl=(SF-AK)/(S.sup.2 -A.sup.2), where S and A denote transfer functions from each speaker to each listener's ear on the same and the opposite sides of each speaker, respectively; F and K denote transfer functions from positions at which each sound image is required to be localized to each listener's ear on the same and the opposite sides of each speaker, respectively. The localizer adds an output of the filter with filter coefficient Hl for one channel to an output of the other-channel filter with filter coefficient Hr for the other channel and outputs the added outputs as filtered rear left and right surround signals. The left and right rear surround signals passed through the localizer are added to front left and right stereophonic signals to be localized at rear left and right positions roughly symmetrically with respect to the listener, respectively.

Surround signal processing apparatus and video and audio signal

A surround signal processing apparatus by which an inputted rear surround signal can be reproduced, together with two-channel front stereophonic signals, through a pair of speakers arranged in front of and in substantially right-and-left symmetry about a listener, in such a way that two sound images of the reproduced rear surround signal can be localized at two predetermined positions relative to the listener. The inputted rear surround signal is processed by a filter. The signal processed by the filter is added to one of the stereophonic signals, and then outputted to one of the pair of speakers. Further, an inversion signal of the filter-processed signal is added to the other of the stereophonic signals, and then outputted to the other of the speakers. Here, the transfer characteristics of the filter are determined as follows: (F-K)/(S-A), where S denotes transfer characteristics between one of the speakers and one of the listener's ears positioned on the same side as the speaker, respectively; A denotes transfer characteristics between one of the speakers and one of the listener's ears positioned on an opposite side to the speaker, respectively; F denotes transfer characteristics between one of the two positions at which two sound images are required to be localized and one of the listener's ears positioned on the same side as the image position, respectively; K denotes transfer characteristics between one of the two positions at which the two sound images are required to be localized and one of the listener's ears positioned on an opposite side to the image position; and/denotes a reverse convolution calculation.

A surround signal processing apparatus, by which an inputted rear surround signal can be reproduced, together with two-channel front stereophonic signals, through a pair of speakers arranged in front of and in substantially right-and-left symmetry about a listener, in such a way that two sound images of the reproduced rear surround signal can be localized at two predetermined positions relative to the listener. The inputted rear surround signal is processed by a filter. The signal processed by the filter is added to one of the stereophonic signals, and then outputted to one of the pair of speakers. Further, an inversion signal of the filter-processed signal is added to the other of the stereophonic signals, and then outputted to the other of the speakers. Here, the transfer characteristics of the filter are determined as follows: (F-K)/(S-A), where S denotes transfer characteristics between one of the speakers and one of the listener's ears positioned on the same side as the speaker, respectively; A denotes transfer characteristics between one of the speakers and one of the listener's ears positioned on an opposite side to the speaker, respectively; F denotes transfer characteristics between one of the two positions at which two sound images are required to be localized and one of the listener's ears positioned on the same side as the image position, respectively; K denotes transfer characteristics between one of the two positions at which the two sound images are required to be localized and one of the listener's ears positioned on an opposite side to the image position; and / denotes a reverse convolution calculation.

A level detection circuit comprises a peak value detection and holding circuit having a capacitor which detects and holds the peak value of an input signal by charging the capacitor, an operation control circuit for supplying the input signal to the maximum value detection and holding circuit during a specific time interval to perform maximum value detection and holding operation, a discharge circuit which performs constant current discharge of a charged electric charge in the capacitor of the maximum value detection and holding circuit after the specific time interval, and a detection circuit for detecting the level of the input signal by measuring the time interval between a time point the constant current discharge of the capacitor by the discharge circuit is initiated and a time point the terminal voltage of the capacitor reaches a specific voltage.

Level detection circuit

A bias current setting apparatus is used in a magnetic recording and reproducing apparatus having a bias current supplying circuit and a magnetic head for recording an audio signal with the bias current on a magnetic tape. The bias current setting apparatus comprises an oscillator for oscillating signals of different frequencies, said signals of different frequencies being recorded and reproduced on and from the magnetic tape in the magnetic recording and reproducing apparatus, a circuit for varying the current value of the bias current, a first detector for detecting the signal of different frequencies which have been recorded and reproduced, a filter for separating a harmonic component of the signal of a frequency which have been recorded and reproduced, a second detector for detecting the output signal of the filter a converter for converting the output signals of the first and second detector which have been selectively supplied thereto into digital signals, and a computer for controlling the bias current setting circuit with a stored program system responsive to the digital signals supplied from the converter thereby varying the bias current value and setting the same at a current value appropriate to the recording on the magnetic tape. The computer varies and sets the bias current value so that the levels of the signals of different frequencies detected by the first detector fall within the predetermined frequency characteristic specification range and distortion factor measured responsive to the output signals of the first and second detectors falls within the predetermined distortion factor characteristic specification range.

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Tokyo, Japan

Tomohiro Mouri