Abstract: An apparatus for restoring a symbol timing of a signal received at a receiving side of a digital communication system.

Abstract: An adaptive equalizing system equalizes an unequalized signal and performs carrier recovery for use in a digital communication receiver. An equalizing coefficient is initialized by a constant modulus algorithm (CMA) and the initialized equalizing coefficient is more finely updated by a stop-and-go algorithm (SGA). When the convergency by the CMA reaches a predetermined threshold value, carrier recovery is performed, while when an average value of the phase error during performing the carrier recovery is less than another predetermined threshold value, the equalizing algorithm is converted into the SGA. Thus, the adaptive equalizing apparatus can equalize the received signal more simply and reliably.

Abstract: An apparatus for restoring a symbol timing of a signal received at a receiving side of a digital communication system.

Abstract: An interlaced-to-progressive scanning converting apparatus for double-smoothing which prevents picture deterioration wherein the scanning method for a television signal is converted from an interlaced scanning method into a progressive scanning method, and a method therefor. The apparatus includes a double-smoothing circuit including a median-filter for median-filtering an interlaced scanning signal, a censoring circuit for censoring the median-filtered signal according to predetermined bias values, an order statistics filter (OSF) for setting a predetermined weighing coefficient according to the censored signal. The apparatus further includes an interlaced-to-progressive converter for converting the double-smoothed interlaced scanning signal into a progressive scanning signal. The apparatus and corresponding method, thus, prevent picture deterioration phenomena such as inter-line flickering, line crawling or stepped-shaped edges.

Abstract: A median filter adaptively increases a window size when there is a possibility that an impulse noise will be present in the median value. When it is determined that an impulse noise is not present in the median value obtained as a median-filtering result, the median filter checks whether or not an impulse noise is present in a target pixel value which is to be subjected to median filtering. When there is a possibility that an impulse noise is present in the target pixel value, the median filter outputs the median value. On the other hand, when an impulse noise is not present in the median value as a check result, the median filter outputs the input target pixel value. Accordingly, an impulse noise can be effectively eliminated from a video signal mixed with a positive impulse noise and a negative impulse noise, while the edge change of the video signal produced by the median filter itself can be minimized. An adaptive median filter is also described.

Abstract: A multilevel nonlinear filter in a HD-MAC decoder, for performing intra-frame filtering corresponding to a post processing, and for performing a progressive scan conversion using edge information includes a delay unit for delaying an input image signal and providing both 1H- and 2H-delayed signals, an edge level estimation signal generating unit for generating first and second window mask data from the input image signal and the delayed signals, and performing a high-speed bubble sort for the generated first and second window mask data, thereby providing first and second estimation signals, an absolute difference signal generating unit for generating an absolute difference signal, an edge detection unit for comparing the output absolute difference signal with a predetermined threshold value, thereby producing edge detection information on a current pixel, and a noise suppression unit for median-filtering the first and second estimation signals and the information on the current pixel in case of edge detection