Abstract: A digital audio broadcast receiver detects frame synchronization signals, measures the pulse widths of and intervals between the detected frame synchronization signals, and stores this information in a memory, together with a history of counts of frame synchronization signals, and stores this information in a memory, together with a history of counts of frame synchronization signals of certain widths detected at certain intervals. This information is retained in the memory until frame synchronization is acquired, as determined from the stored count values, enabling frame synchronization to be acquired quickly despite the false detection of frame synchronization signals due to noise.

Abstract: A multipath noise reducer extracts a high-frequency signal from a demodulated signal obtained from a frequency-modulated signal, and generates a noise reduction coefficient from the extracted high-frequency signal. The demodulated signal is also separated into high-frequency and low-frequency components, the high-frequency component is multiplied by the noise reduction coefficient, and the resulting product is added to the low-frequency component. An output signal is thereby obtained in which the spike noise that characterizes multipath reception of a frequency-modulated signal is reduced with relatively little distortion of other parts of the signal, including the parts between noise spikes. The distortion can be further reduced by replacing the demodulated signal with an interpolated signal during noise spikes before the low-frequency component is separated.

Abstract: A digital audio broadcast receiver is tuned by performing a sliding correlation on data demodulated from a phase reference symbol, correlating the demodulated data with known data at negative carrier numbers and, separately, with known data at positive numbers, thus obtaining a lower correlation coefficient and an upper correlation coefficient. The peak sum of these two correlation coefficients, as found in the sliding correlation, is recognized as valid if the two correlation coefficients do not differ greatly in magnitude, and do not differ greatly in phase angle. The tuning is adjusted only according to sliding shifts corresponding to valid peak sums, thereby avoiding frequency control errors.

Abstract: A digital broadcast receiver receiving a multi-carrier signal controls the timing of a sampling window, used in demodulation of the multi-carrier signal, according to a channel impulse response waveform obtained by processing of a synchronization signal occurring in the multi-carrier signal. The values in the channel impulse response waveform are multiplied by corresponding weighting coefficients, the resulting products are added to obtain a weighted sum, and the timing of the sampling window is adjusted according the weighted sum. Under a wide variety of reception conditions, this control scheme avoids inter-symbol interference, and leaves adequate timing margins to accommodate new signal components that may appear.

Abstract: A noise removal unit mounted on a car radio according to the invention removes multipath noise and pulse noise from FM demodulated signals. At this time, the noise removal unit removes all of the multipath noise. Also, in case where the generation density of noise is high, the noise removal unit reduces the detection sensitivity so as not to detect pulse noise, particularly of small level, as noise. Comparing to multipath noise, pulse noise is noise rendering a large correction error than multipath noise. Therefore, in case where the generation density of pulse noise is high, by adapting the unit not to remove pulse noise of small level, it is made possible to reduce distortion of the FM demodulated signals to a minimum. Accordingly, it is made to reduce deterioration of the quality of FM voices to a minimum.

Abstract: An impulse noise detector detects impulse noise in an audio signal by filtering out the audio components of the signal, then comparing an envelope of a filtered signal with a threshold obtained as a moving average of the envelope. Short-duration impulse noise is thereby detected without detecting tone bursts and other fast-rising signals of longer duration. The envelope may be taken directly from the filtered signal, or from a difference signal obtained from a preliminary envelope of the filtered signal, to emphasize impulse noise when distorted audio components leak into the filtered signal.

Abstract: A digital audio broadcasting receiver comprises a phase error detector for detecting a phase error from data from a differential demodulator, an average value processing unit for determining the average value of phase errors, a memory for storing the phase errors of the carriers outputted from the phase error detector, and a phase error correcting unit which excludes a phase error whose sign is opposite to that of the average value among the phase errors stored in the memory, and determined the average value of phase errors again, thereby making it possible to obtain a phase error signal which is less affected by leakage from other carriers.

Abstract: A multipath noise reducer detects and removes the individual noise spikes occurring in an interval of multipath noise, thereby reducing the multipath noise with relatively little distortion of the output signal. The threshold signal used to detect multipath noise is varied depending on reception conditions. The gate pulses indicating the presence of multipath noise spikes are preferably expanded by variable amounts, depending on both reception conditions and the signal level. Multipath noise spikes are preferably replaced by a smoothed signal. These provisions further reduce perceived distortion of the audio output signal.

Abstract: A noise reducer generates a gate signal by detecting noise in a demodulated signal, and changes the lengths the gate pulses indicating the presence of noise according to the electric-field strength of a radio signal from which the demodulated signal has been obtained. The demodulated signal is modified during intervals indicated by the gate pulses, to reduce the noise. The amount of change of the gate-pulse lengths is preferably increased as the electric-field strength decreases. Noise can then be removed satisfactorily under even weak electric-field conditions.

Abstract: To control the oscillation frequency of a local oscillator, a digital broadcast receiver demodulates a phase-reference symbol contained in an orthogonal frequency-division multiplexed broadcast signal to obtain an array of complex values, selects several sets of values from the array, multiplies each selected value by the complex conjugate of a value offset by N positions in the array (where N is a fixed integer that may be equal to zero), averages the results in each set, takes differences between the average values, or between sums of these average values, thereby obtains two difference values, and calculates a frequency offset from the difference values. Each set of values is taken from positions at which the known reference-symbol values satisfy certain conditions in relation to the known values at adjacent positions.

Abstract: To control the oscillation frequency of a local oscillator, a digital broadcast receiver demodulates a phase-reference symbol contained in an orthogonal frequency-division multiplexed broadcast signal, modifies the resulting frequency-domain data by multiplication with complex conjugates of known data encoded in the phase-reference signal, under different assumed frequency offsets, converts the modified data to time-domain data, and thereby detects a first frequency error equal to a multiple of the subcarrier spacing and a second frequency error not exceeding the subcarrier spacing. Differential phase error is also detected. The oscillation frequency is adjusted to correct the first frequency error and differential phase error; then the second frequency error is used to correct for ambiguity in the differential phase error.

Abstract: Telecine signal conversion method for converting an interlaced scan telecine signal generated by 2-3 pull-down system, wherein a picture of the first frame is converted into an interlaced signal of the first and second fields and a picture in the following second frame is converted into an interlaced signal in the third, fourth and fifth fields, into a progressively scanned telecine signal comprising steps of detecting a pull-down phase of the interlaced scan telecine signal, specifying the first and second fields based on the detected pull-down phase, composing picture signals of the specified first and second fields and generating progressively scanned telecine signals from the picture signals of the first and second frames, and specifying the third and fourth fields based on the detected pull-down phase, composing picture signals of the specified third and fourth fields and generating progressively scanned telecine signals from the picture signals of the third, fourth and fifth frames.

Abstract: A digital audio broadcast receiver searches for a receivable digital audio broadcast signal by first searching for a signal, having at least a predetermined power level, in which frame synchronization symbols can be detected. This stage of the search is made by searching a known frequency grid, or by scanning in steps approximately equal to the bandwidth of the digital audio broadcast signal. After frame synchronization symbols have been detected, the receiver attempts to find the center frequency of the received signal, changing the receiving frequency in steps less than the bandwidth of the digital audio broadcast signal, if necessary. A prompt indication that a receivable digital audio broadcast signal has been found is given when frame synchronization symbols are detected, or when the center frequency is found.

Abstract: To control the oscillation frequency of a local oscillator, a digital broadcast receiver demodulates a phase-reference symbol contained in an orthogonal frequency-division multiplexed broadcast signal, modifies the resulting frequency-domain data by multiplication with complex conjugates of known data encoded in the phase-reference signal, under different assumed frequency offsets, converts the modified data to time-domain data, and thereby detects a first frequency error equal to a multiple of the subcarrier spacing and a second frequency error not exceeding the subcarrier spacing. Differential phase error is also detected. The oscillation frequency is adjusted to correct the first frequency error and differential phase error; then the second frequency error is used to correct for ambiguity in the differential phase error.

Abstract: A picture replacement system for replacing a specified area of an original picture, with a desired picture comprising at least one camera for shooting an original picture of the subject; at least one irradiation unit for radiating a specified area of the subject with a predetermined invisible light ray; a picture generation unit for generating a desired picture that matches a size of the specified area; a detection unit for detecting the invisible light ray reflecting from the specified area that has passed around an obstruction in front of the specified area of the subject without being obstructed; a key signal generation unit for generating a key signal indicating a replacement area of the original picture based on a detection result of the detection unit; and a replacement unit for replacing the specified area within the replacement area with a desired picture corresponding to the key signal indicating the replacement area.

Abstract: To avoid degradation of the acoustic signal radiated from the opening of the ducted horn of a ducted horn type speaker, under influence of the ducted horn, below the characteristic of the speaker itself, and input terminal for receiving an audio signal, a non-recursive digital filter for varying the input audio signal, a power amplifier for amplifying the varied signal, and speaker for replaying the amplified signal are provided. The non-recursive digital filter realizes the inverse characteristic of the transfer characteristic of the ducted horn.

Abstract: An information reproduction apparatus capable of reducing or eliminating the mute period when a pickup jumps during the reproduction or when a disk is changed in an information reproduction system provided with a disk changer mechanism for selecting one disk from plural disks, or when a disk is forced to change, or an information reproduction apparatus of displaying the time information corresponding to the actual outputting time of information from the output terminal by correcting the time information included in the information read from the recording medium or determined by the recording address, or an information reproduction system provided with a disk changer mechanism capable of checking the contents of other disks during reproduction, or system of reproducing only parts of information which allow to view the contents of all disks.

Abstract: A disc apparatus includes a readout unit, an audio signal output unit, a memory, a switch, and a controller. The readout unit reads out data from a disc wherein the data includes at least digital audio data. The audio signal output unit produces an audio signal output in accordance with the digital audio data. The memory stores the digital audio data read from the disc by the readout unit. The switch switches the digital audio data supplied to the audio signal output unit between the digital audio data stored in the memory and the digital audio data currently being read by the readout unit.

Abstract: An information reproduction apparatus capable of reducing or eliminating the mute period when a pickup jumps during the reproduction or when a disk is changed in an information reproduction system provided with a disk changer mechanism for selecting one disk from plural disks, or when a disk is forced to change, or an information reproduction apparatus of displaying the time information corresponding to the actual outputting time of information from the output terminal by correcting the time information included in the information read from the recording medium or determined by the recording address, or an information reproduction system provided with a disk changer mechanism capable of checking the contents of other disks during reproduction, or system of reproducing only parts of information to allow the monitoring of the contents of all disks.

Abstract: A digital signal which is recorded on a recording medium with being encoded is duplicated to another recording medium without being decoded. An audio signal is recorded and/or reproduced using data recorded in a TOG of the recording medium. A first data signal (2-channel audio signal) is intermittently recorded on and/or reproduced from a first area of the recording medium, and a second data signal (other 2-channel audio signal) is intermittently recorded on and/or reproduced from a second area of the recording medium during a period in which the first data signal is not recorded or reproduced.