Abstract: A data decoding apparatus and method are provided for decoding a reproduction signal in a digital magnetic recording/reproducing apparatus. A Viterbi decoder having a single channel is constructed such that the noise level corresponds to that of an EnPR4 system and the aperture ratio of an eye pattern corresponds to that of a PR(+1, −1) system, thereby improving the efficiency of the Viterbi decoder and allowing state detection by the PR(+1, −1) system. Data can be decoded by a system having a PR4 or EnPR4 channel or selectively by other various systems.

Abstract: A peak detector for a maximum likelihood decoding system, using an automatic threshold control (ACT), and a method therefor are provided. In the peak detector, positive and negative peak values are detected from an input signal having digital information, based on positive and negative threshold values, and then each threshold value is evaluated according to positive and negative values of the input signal, to reset each threshold value to a predetermined value based on the detected peak value having the opposite polarity thereto. Accordingly, data can be detected exactly, improving performance of Viterbi decoding.

Abstract: A Viterbi decoding circuit for decoding an input signal is provided. The circuit contains a detector, a first converter, a Viterbi decoder, a second converter, and a selector. The input signal is grouped into a current and subsequent input signal group. The detector detects negative peak data values and positive peak data values from the current input signal group. The first converter converts the positive and negative peak data in a reverse direction to produce reverse positive and negative peak data, respectively. The Viterbi-decoder decodes the reverse positive and negative peak data with respect to a predetermined number of initial states and generates current reverse decoded data groups which respectively correspond to a plurality of channels and respectively correspond to the initial states. In addition, the Viterbi decoder generates a control signal based on a state of initial decoded data corresponding to the subsequent input signal group.

Abstract: Magnetic recording device and method are provided. The magnetic recording device includes a shaping driver for positive and negative signals whose polarities are reversed, corresponding to the digital information, a push-pull portion for generating a recording current corresponding to the positive and negative signals and generating a transient pulse current during reversal of the polarity of the recording current, and a current switch for switching a current flowing through the push-pull portion in response to the positive and negative signals. The digital signal is recorded on the magnetic recording medium on the basis of the transient pulse current. Therefore, without an additional recording equalizer, rise characteristics of a head current is improved and the demand of small-size and low-power is satisfied.