A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

Deterioration of convergence performance or operational stability due to an increase in constraint length is suppressed when coefficients are updated, so that decoding performance is improved. A decoding device according to the present technology includes an adaptive equalization unit that performs adaptive equalization, an adaptive maximum likelihood decoding unit that causes an identification point of maximum likelihood decoding to adaptively follow a characteristic of an input signal, a target waveform generation unit that, by convoluting a partial response coefficient into a decoded value, generates an equalization target waveform of the adaptive equalization which is performed by the adaptive equalization unit, an error signal generation unit that generates, as an equalization error signal, an error signal between the equalization target waveform and an equalized signal, and a coefficient updating unit that, through least-square-method computation for minimizing a correlation between the decoded value and the equalization error signal, updates the partial response coefficient which is used by the target waveform generation unit to generate the equalization target waveform.

According to one embodiment, a magnetic disk device includes a disk including two first servo sectors and at least a second servo sector, a head, and a controller, wherein the first servo sector includes burst data and a first data pattern written before the circumferential direction of the burst data, the second servo sector includes the burst data, the first data pattern, and a second data pattern written after the circumferential direction of the burst data, a first frequency of the first data pattern is different from a second frequency of the second data pattern, and a first length of the first data pattern is different from a second length of the second data pattern.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

A deep neural network (DNN) media noise predictor configured for one-dimensional-magnetic (1DMR) recording or two-dimensional-magnetic (TDMR) is introduced. Such architectures are often combined with a trellis-based intersymbol interference (ISI) detection component in a turbo architecture to avoid the state explosion problem by separating the inter-symbol interference (ISI) detection and media noise estimation into two separate detectors and uses the turbo-principle to exchange information between them so as to address the modeling problem by way of training a DNN-based media noise estimators. Thus, beneficial aspects include a reduced bit-error rate (BER), an increased areal density, and a reduction in computational complexity and computational time.

Deterioration of convergence performance or operational stability due to an increase in constraint length is suppressed when coefficients are updated, so that decoding performance is improved. A decoding device according to the present technology includes an adaptive equalization unit that performs adaptive equalization, an adaptive maximum likelihood decoding unit that causes an identification point of maximum likelihood decoding to adaptively follow a characteristic of an input signal, a target waveform generation unit that, by convoluting a partial response coefficient into a decoded value, generates an equalization target waveform of the adaptive equalization which is performed by the adaptive equalization unit, an error signal generation unit that generates, as an equalization error signal, an error signal between the equalization target waveform and an equalized signal, and a coefficient updating unit that, through least-square-method computation for minimizing a correlation between the decoded value and the equalization error signal, updates the partial response coefficient which is used by the target waveform generation unit to generate the equalization target waveform.

According to one embodiment, a magnetic disk device includes a disk including two first servo sectors and at least a second servo sector, a head, and a controller, wherein the first servo sector includes burst data and a first data pattern written before the circumferential direction of the burst data, the second servo sector includes the burst data, the first data pattern, and a second data pattern written after the circumferential direction of the burst data, a first frequency of the first data pattern is different from a second frequency of the second data pattern, and a first length of the first data pattern is different from a second length of the second data pattern.

A receiver device receives a signal via a communication channel, the signal (i) having been transmitted by a transmitter device, and (ii) corresponding to a pseudorandom bit sequence (PRBS). The receiver device correlates the received signal with a known signal to generate a correlation signal. The known signal includes the PRBS. The receiver device identifies one or more characteristics of the correlation signal, and determines one or more parameters of the communication channel using the identified one or more characteristics of the correlation signal. The receiver device i) uses the one or more parameters corresponding to the communication channel to process subsequent signals received via the communication channel, and/or ii) communicates the one or more parameters to the transmitter device to prompt the transmitter device to preprocess subsequent signals to be transmitted via the communication channel by the transmitter device.

Data detection capability is improved by whitening crosstalk noise from an equalization signal and detecting binary data. Each of a plurality of detection signals is input to one of a plurality of adaptive equalizers, and outputs of the plurality of adaptive equalizers are computed to obtain an equalization signal for returning light at the time of shining of light onto bounds including a target track subject to data detection and adjacent tracks of an optical recording medium having a plurality of tracks formed thereon. Crosstalk noise from the adjacent tracks included in the equalization signal obtained by this multi-input adaptive equalization process is whitened first, followed by a binarization process. Also, an equalization error is found, and supplied as a control signal for adaptive equalization. Further, a whitening factor updating process is also performed to adaptively update a filter factor of a whitening filter.