摘要:
A network configuration management includes the steps of sending from the management terminal (1100) participation terminal information stored in the management terminal; receiving by the participation terminal (1200, 1300, 1400) other than the management terminal, participation terminal information sent from the management terminal (1100); judging by the participation terminal other than the management terminal, whether or not the participation terminal can communicate with another participation terminal device that is participating in a wireless network (1010); sending a communication availability judgment result which is obtained by the judging step, from the participation terminal other than the management terminal to the management terminal (1100); and determining by the management terminal (1100), a participation terminal that should be excluded from the wireless network (1010) in accordance with the communication availability judgment result, and deleting by the management terminal device, from the participation terminal information the participation terminal that should be excluded from the wireless network (1010), thereby updating the participation terminal information which is stored in the management terminal.
摘要:
An impulse noise reducer detects impulse noise in an audio signal by detecting and smoothing the high-frequency amplitude of the audio signal, attenuating the non-smoothed amplitude according to the smoothed amplitude, and comparing the attenuated amplitude with a threshold. Impulse noise is discriminated from high-frequency audio components because the latter tend to occur in longer-lasting bursts and are therefore attenuated more strongly. The impulse noise reducer is simplified because it does not have to perform intermediate-frequency signal processing, and its sensitivity is not affected by adjacent-channel signals because these signals are substantially absent from the audio signal. The impulse noise reducer can be implemented by digital signal processing, and is suitable for use in a medium-wave AM audio broadcast receiver.
摘要:
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.
摘要:
A digital sound broadcasting receiver and method receives a radio wave from a digital sound broadcasting station, demodulates the radio wave into baseband signals at a tuner, subjects the signals to demodulation, performs error detection and error correction at signal processors to obtain digital data, and inputs the digital data into an audio circuit to obtain audio or data output. A CRC error rate detector 13 for a fast information channel (FIC) for APC pseudo lock releasing action on demodulating the signals is arranged to determine, based on the possibility of an error rate of an error-detecting code (CRC) of the FIC, whether an APC pseudo lock state occurs, and to control releasing action for the APC pseudo lock state.
摘要:
A receiving device (50) is provided to allow appropriate clock regeneration even for a VBR TS when a stream including video and audio data, such as an MPEG2 TS, is transmitted or received in real time through a network having jitter. When the received packet data is stored in a memory (53) and the packet data is output in accordance with time information added to the received packet data, a clock frequency deviation between a sending device and a receiving device is calculated on the basis of the integration result of the amount of the received packets temporarily stored in the memory (53), the number of the received packets which have been processed, and the measurement result of the integration time used for integrating the amount of the received packets. A read timing offset of the received packet is obtained on the basis of the calculation result of the clock frequency deviation.
摘要:
An audio signal noise reduction system comprises a noise detecting circuit 11 for detecting a noise from an audio signal and outputting a detection signal indicating a start time and an end time of a noise period of the noise, an LPF 12 for extracting a low frequency component of the audio signal, an HPF 14 for extracting intermediate and high frequency components of the audio signal, a polynomial interpolation circuit 13 for polynomial-interpolating the noise period of the low frequency component being extracted, a mute circuit 15 for muting an output level of the noise period of the intermediate and high frequency components being extracted, and a signal synthesizing circuit 16 for synthesizing the low frequency component whose noise period is polynomial-interpolated and the intermediate and high frequency components the level of whose noise period is suppressed to thus output the audio signal.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.