43 results about "Channel equalisation" patented technology

Provided is a read channel incorporated in a storage device to process signals read from a storage medium. The read channel includes an equalizer equalizing input read signals to produce equalizer output signals. A detector senses an adjusted equalizer output signal to determine an output value comprising data represented by the input read signals. An equalizer adaptor receives the output value from the detector to determine a first error signal used to adjust the equalizer operations. A component adjusts the equalizer output signals being transmitted to the detector, wherein the component is adjusted by a second error signal calculated from the output value from the detector, wherein the first and second error signals are different.

The invention discloses a communication system, a communication method, a multichannel adaptive equalizer and an OFDM (orthogonal frequency division multiplexing) signal demultiplexing method. The OFDM signal demultiplexing method includes the steps: receiving OFDM optical signals multiplexed by N-channel optical subcarrier waves, demodulating the OFDM optical signals by respectively using series intrinsic light different in angular frequency so as to obtain corresponding OFDM electrical signals; and after adjacent frequency band signals except for baseband signals are subjected to attenuation of a low-pass filter, sampling the OFDM electrical signals in each channel so as to obtain corresponding OFDM electrical signal sampling values, and then reducing data carried by the corresponding optical subcarrier waves in each channel by using a multichannel balance matrix to multiply by the N-channel OFDM electrical signal sampling values. The OFDM signal demultiplexing method has the advantages that a receiving end does not require strict match of sampling time of signal demodulation in each channel, sampling rate is determined by modulating signal rate carried by single optical carrier wave, ADC (analog-to-digital converter) bottleneck restriction can be bypassed, and the method is applicable to the high-speed optical communication system.

A filter bank receiver (FBMC) effecting a carrier frequency offset compensation in the frequency domain. The receiver comprises an FFT module extended by the overlap factor (610), a module (630) offsetting a predetermined number of subcarriers at the output of the FFT followed by a filter for reducing interference between subcarriers (640), the number of subcarriers and the coefficients of the interference reduction filter being determined from an estimation () of the frequency offset. The vector of samples thus obtained is then the subject of channel equalisation (650) before being filtered by a battery of analysis filters and spectrally de-spread (660). Finally, after spectral de-spreading, the vector of samples is demodulated by an OQAM demodulation (670) so as to recover the transmitted data.

A new method of designing digital filters for specific magnitude and phase requirements that minimises the filter's group-delay given arbitrary error tolerances is presented in this patent application. The method is extended to include optimising the original filter design based on the group-delay minimisation routine. A particular example that describes the linearisation of a filter channel under these conditions and given these constraints is shown. Embodiments may be applied to any digital filter design technique implemented in software, hardware, or a combination of both for applications such as equalisation or any area where filters are useful. The method disclosed is broadly applicable in the field of signal processing and may be used to advantage, for example in: channel equalisation, speaker and audio correction, echo-cancellation, control applications, digital audio broadcast, sonar and ultrasonics.

A method of reducing multiple access interference in a CDMA radio system uses a plurality of rake fingers to pre-process received signals but without demodulation or de-spreading. The outputs of the rake fingers are combined, normalised and then processed by an adaptive equaliser to recover orthogonality lost in transmission. The equaliser output is then subject to de-spreading and de-scrambling to recover the desired user signals. The equaliser is preferably adaptive order, the length being adapted in dependence upon the instantaneous signal to noise ratio.

Methods for discontinuing interference-filter pre-coding of 8-VSB digital television (DTV) signals during ancillary-service transmissions are disclosed that do not disrupt reception of main-service DTV signals by receivers already in use. Receivers are disclosed for receiving ancillary-service transmissions without interference-filter pre-coding, which receivers include adaptive channel-equalization filters and subsequent decoders for CCC. The subsequent decoders for CCC respond to data slicing of adaptive channel-equalization filter responses that avoid the reduction of signal-to-noise ratio (SNR) caused by post-comb filtering. Certain of these M / H receivers employ selective post-comb-filtering to flatten the frequency spectrum of main-service components of received 8-VSB DTV signals, while leaving the frequency spectrum of M / H-service components of received 8-VSB DTV signals as received. This is done to generate signal from which filter coefficients for the channel-equalization filters are determined. Certain of these M / H receivers employ decision-feedback equalization (DFE) techniques, which techniques are unaffected by selective interference-filter pre-coding.

The invention belongs to the array signal technology, and relates to a method of equalizing unmatched channels in a certain bandwidth. The channel equalization method comprises the following steps: 1, a frequency domain equalization filter is converted into an N-point filter, and N is selected to be the least power no smaller than L, and the N-point frequency feature e<N><O> of the frequency domain equalization filter is solved; 2, each section filter coefficient for segmented equalization is solved; and 3, the eN is used for carrying out equalization processing on a baseband complex signal xA of the to-be-equalized channel, and a complex signal sequence xAE after equalization is obtained. The storage space needed by channel equalization can be reduced, the cancellation performance between channels is improved, the array processing performance is thus enhanced, and requirements of multichannel array signal processing by a modern communication system, a phased array radar system and the like can be met.

A method for dynamically scheduling multi-receive channel signal equalizer tasks, the method comprising: a computing device determining an estimated maximum Doppler frequency and an estimated delay spread of a wireless communication channel at a specific time; the computing device is based on The estimated maximum Doppler frequency and the estimated delay spread determine a task queue form and an update period of a predictive model order; the computing device selects a change in a predictive model order search range based on the determined task queue form rate; and the computing device generates a plurality of task control signals within a time period to control equalizer coefficients based on the task queue form, the update period of the predictive model order, and the search range of the predictive model order.