Abstract: A transmission method of a digital broadcast which is compatible with the DVB-T terrestrial digital broadcast system in Europe and saves a battery in a mobile terminal is provided. Superframes in DVB-T are divided into units each including plural symbols so that an integer number of TS packets can be carried in each slot. At least one slot is used to transmit one service. Energy dispersion, Reed-Solomon coding, byte interleaving, convolutional coding, and time interleaving are applied to each service. When services for mobile terminal reception and services for fixed terminals are transmitted as the provided services, null packets may be transmitted before and after the slot carrying the mobile receiver service so that the fixed reception service and the mobile reception services are not mixed. If the fixed terminal handles TS packets of the mobile reception service as error packets, it could have no problem in reception.

Abstract: Digital broadcasting for transmitting program data including at least one of digital audio data and digital video data with other information is carried out by using terrestrial waves. The program data, download data corresponding to contents of the program data, and reference information correlating the download data with the program data are multiplexing with each other. The multiplexing signals are transmitted over a specific frequency band.

Abstract: In a null symbol detection device, at the time of receiving a terrestrial digital broadcast, a null symbol can be stably detected even under a fading environment. A synchronous addition buffer group is provided subsequent to an amplitude detector so as to synchronously add an OFDM signal at a null symbol repetition period. A moving average processing unit performs a moving average operation upon synchronous addition data with the number of samples corresponding to a null symbol to output a moving average value. A transmission mode determining unit detects the minimum value among the moving average values normalized in a correction processing unit and compares levels of the minimum values to determine a reception mode. A null position detector generates a synchronous pulse at a null position.

Abstract: A digital audio broadcasting receiver includes: an analog-digital converter for converting a plurality of transfer frames from an analog signal format into a digital signal format based on a clock signal having a fixed frequency and for outputting the first transfer frame; a demodulator for demodulating the first transfer frame from a first frame processing start position for the first transfer frame; an audio decoder for generating audio data containing a plurality of audio samples based on the data symbol contained in the first transfer frame which has been demodulated by the demodulator; a transfer path characteristics calculator for generating a transfer path characteristics signal representing transfer path characteristics based on the reference symbol contained in the first transfer frame which has been demodulated by the demodulator; and a frame processing start position control section for controlling a second frame processing start position for the second transfer frame, by outputting to the demodula

Abstract: The object of the invention is to provide a transmission method of the digital broadcasting that can be carried out under the digital broadcasting using the terrestrial waves and does not need complicated operations of using GUI screen.

Abstract: A stereo ultradirectional microphone apparatus for detecting a sound to produce stereo sound signals, comprises: first and second ultradirectional microphones arranged side by side with a given distance in parallel for converting a sound into first and second sound signals respectively, first and second delays for delaying an output of the first and second microphones by a delay time .tau. respectively, and first and second subtractors for subtracting for subtraction between the first sound signal and an output of the second delay and subtracting for subtraction between the second sound signal and an output of the first delay. The delay time .tau. corresponds to a difference between the timings of a sound from a sound source in a direction making a clockwise angel .theta. from the front where a dead angel should be made. The subtraction provides the dead angle. Similarly, a dead angle on the side is also made to obtain a stereo characteristic.

Abstract: In an echo canceller, a first adaptive filter (1) estimates an impulse response of an echo path between reception and transmission side by an NLMS algorithm to synthesize a pseud echo, while a second adaptive filter (3) determines whether there is an echo path change or a double talk. A voice detector (8) detects a short time power of the received input signal (x) to determine whether far-end speech is present or absent. The voice detector controls the second adaptive filter (3) to execute adaptation of the second adaptive filter for renewal of an impulse response of an echo path when far-end speech is present and otherwise to suspend the adaptation of the second adaptive filter when far-end speech is absent, while a double talk detector (9) controls the first adaptive filter to execute or suspend adaptation of the first adaptive filter according to the determination results of the voice detector.

Abstract: An array microphone is a directional microphone having an improved directional characteric in which both the sensitivity and the sound pressure frequency response are uniform within the recording area and more particularly, the quality and level of sound remain unchanged. The array microphone includes a microphone array including a plurality of microphone units, and a two-dimensional filter for filtering an output of the microphone array in the dimensions of both time and space. When the two-dimensional filter is a digital filter and varied in its two-dimensional filter coefficient and sampling frequency, the array microphone serves as a variable directional microphone whose directional characteristic can be varied with the sound quality and level remaining unchanged throughout the recording area.

Abstract: A howling canceller includes a group of filters for dividing an output of a microphone into a plurality of frequency bands, a transfer characteristic estimation unit for estimating a transfer characteristic (i.e.-impulse response) of a low frequency range in an echo path extending from a loudspeaker to the microphone, an echo signal estimation unit for producing an approximate echo signal of the low frequency range proceeding from the loudspeaker to the microphone, a subtracter for subtracting an output of the echo signal estimation unit from an output of a low-pass filter of the filters, and an adder for adding an output of the subtracter to outputs of the filters other than the low-pass filter.

Abstract: Process for inhibiting crust formation in reactors used for polymerising alpha-olefines, such as ethylene and propylene, in the presence of particles of catalytic solids containing titanium and chlorine in the combined state.The polymerisation is carried out in the presence of an amount of a silicone oil which is less than 1% by weight, relative to the weight of catalytic solid.