74 results about "Spectral mask" patented technology

Disclosed are: a variety of methods and apparatuses for aggregating a plurality of carriers and using the carrier aggregation in a wireless connection system; and a variety of methods and apparatuses for providing information on the structure of a carrier generated by aggregating a plurality of carriers. A method for transmitting and receiving carrier group information, according to one embodiment of the present invention, includes the steps of: a mobile terminal transmitting a first message containing multi-carrier performance information of the mobile terminal to a base station; and the mobile terminal receiving, from the base station, a second message containing allocation information on the wireless resource allocated on the basis of the multi-carrier information. Here, multi-carrier performance information includes a spectral mask-type parameter for the supportable multi-carrier of the mobile terminal.

The present patent application comprises a transmitting method and apparatus 240. A signal source 241 provides an input signal to a low-pass filter 242 which filters the input signal to produce a filtered signal. The filter 242 is selectively operable in a first mode in which the input signal is filtered within a narrower bandwidth; and in a second mode in which the input signal is filtered within a broader bandwidth. The filtered signal is output to a modulator 243 which modulates the filtered signal to produce a modulated signal. The modulated signal is output to a transmitter 244 which transmits the modulated signal.

A transmitting unit (12) clips a communication signal (14) to form a threshold-responsive signal (36, 36′) which includes in-band distortion (40) and out-of-band distortion (38). A portion of the out-of-band distortion (38) is notched within rejection bands (48, 50) adjacent to the communication signal's bandwidth (24). But remaining portions of the out-of-band distortion (38) and portions of the in-band distortion (40) are included with the communication signal (14). The remaining portion of the out-of-band distortion (38) causes the communication signal (14) to be in violation of a spectral mask (30). The mask-violating communication signal 14 with out-of-band distortion (38) and in-band distortion (40) is amplified by an RF power amplifier (22). After amplification, a bandpass filter (92) exhibiting fast rolloff regions (110) attenuates the amplified out-of-band distortion (38) causing compliance with the spectral mask (30).

A technique of reducing the Peak-to-Average Power Ratio (PAPR) of Multi-Carrier (MC) modulated signals in which peaks in the baseband signal that lie above a threshold amplitude are detected and used to generate a pulse sequence signal which, after shaping, is subtracted from the baseband signal to reduce its PAPR. The method is spectrally efficient, has a low degree of implementation complexity and hence it is also suitable for low-power, portable implementation. Moreover, it is compatible with existing standard-based Orthogonal Frequency Division Multiplex (OFDM) systems. As an example of the performance of the proposed scheme, the amplifier back-off requirement in a Terrestrial Digital Video Broadcast (DVB-T) system can be reduced from 12 to 6 dB, while satisfying the of out-of-band emission specifications imposed by the Federal Communications Commission (FCC) spectral mask.

Method for designing transmission pulses for ultra-wideband communications systems. A preferred embodiment comprises specifying a spectral description for the pulse. After a spectral description is created, then an approximation of the pulse can be created and well known optimization techniques, such as the least squares technique, can be used to minimize the difference between the approximation and the pulse. If the communications system is operating in the presence of interferers, then the spectral mask can be modified to ensure that the approximation carries no signal information in frequencies corresponding to the interferers.

A transmit processor that includes a transmit frequency domain equalizer (TX FEQ) that pre-compensates packets in the frequency domain to flatten transmit filter response to improve spectral mask and reduce PER. The TX FEQ taps may be selected so that the average power at output equals the average power applied to the input. The TX FEQ may be designed to yield 64 QAM packets with no quantization distortion at the input of an Inverse Fast Fourier Transform (IFFT) processor. The 64 QAM constellation map points and TX FEQ gain values are selected to avoid exceeding the bit resolution of the IFFT processor. The tones may be bound together into zones to reduce implementation complexity by reducing the number of TX FEQ taps.

A system and method communicates and generates a Coded Orthogonal Frequency Division Multiplexed (COFDM) communications signal as a plurality of subcarriers. Selected subcarriers are turned ON and OFF while also frequency hopping and spreading the selected ON subcarriers over the frequency domain based on a fixed or variable sample rate to reduce average power for enhanced Low Probability of Interception/Low Probability of Detection (LPI/LPD) and also allow for more transmit power within a spectral mask.

Controlling margins in a DSL modem pair is based on collected operational data. The operational data is analyzed and at least one of the modems in the modem pair is instructed to use a margin-related parameter value to assist the modem pair in meeting a margin target, such as a margin limit imposed by a DSL standard or the like. A controller, such as a DSM Center, a 'smart' modem unit and/or a computer system can collect and analyze the operational data and generate one or more margin-related parameter values. The margin-related parameter value may be a PSD-related value, such as the MAXNOMPSD, MAXNOMATP or PSDMASK parameter used by various ADSL systems, and may be a shaped spectral mask and/or caps or limits on bit loading for use in transmissions between the modems. In some cases, preference bands can be imposed to direct modems to favor and/or avoid certain frequencies in the modem's usable band(s). The operational data may include historical data relating to prior performance of the modem pair and prior margin compliance. A distribution of margins also may be based on operational data and may be estimated as a function of data rate. Using the estimated margin distribution, a distribution of performance parameters also is calculated, including the probabilities of line outages and probabilities of one or more error parameters exceeding minimum levels. Data rates and/or performance-related parameters may be set on the basis of the estimated performance of the system using various margin settings and levels.

A low-power digital communications transmitter (20) includes a programmable digital-processing circuit (22), which may be provided by a digital signal processor (DSP), a programmable direct digital synthesizer (DDS), and a constant-envelope, high power amplifier (32). The DDS (24) is programmed to provide pulse-shaping and IF/RF signal modulation functions. The digital-processing circuit (22) produces only one sample per unit interval (134) and is programmed so that the one sample per unit interval (134) is a frequency-profile index symbol (52″) produced from a I,Q baseband symbol (52′). The DDS (24) converts each frequency-profile index symbol (52″) into a frequency profile (130) that controls the frequency of a synthesizer (56) to induce modulation into a periodic output (68) of the synthesizer. Moreover, the frequency profile (130) is configured to confine spectral emissions within a spectral mask (140).

The embodiment of the invention discloses an audio noise reduction method and a training method of an audio noise reduction model. According to the scheme, the method comprises the steps: acquiring the audio signal to be denoised, processing the audio signal to be denoised to obtain the spectrum feature, inputting the spectrum feature into the convolutional network model to be processed to obtainthe spectrum convolutional feature, and inputting the spectrum convolutional feature into the cyclic network model to be processed to obtain the target spectrum or the target spectrum mask; processingthe target spectrum to obtain a target audio signal; or processing the audio signal to be denoised by using the target spectrum mask to obtain a target audio signal. According to the embodiment of the invention, the neural network structure is applied to singing noise reduction of karaoke recording, so the original signal structure of the singing can be well maintained while the noisy singing issubjected to effective noise reduction, and the obvious hearing distortion after noise reduction is avoided.