Abstract: Disclosed is a digital communication system. A transmission system includes an error correction encoder part carrying out an error correction encoding for additional data inputted through a first path, a multiplexer (MUX) part, a control part, a channel coding part carrying out an RS encoding and a TCM encoding, and a VSB transmission part modulating the channel-coded data by a VSB method and outputting the modulated data.

Abstract: A VHF tuning circuit includes two tuning inductance devices connected in series with each other and having a junction thereof connected to an input terminal, and a first switch diode connected in parallel with the two in series inductance devices, and turned OFF at least when tuning is performed with a low range of a VHF band. A UHF tuning circuit is connected to the input terminal through a second switch diode that is turned ON at least when tuning is performed with a UHF band. The second switch diode is turned OFF when tuning is performed with a low range of the VHF band.

Abstract: A method of aligning a first image with a second image, the method includes approximately locating the second image; scaling the first image to the approximate size of the second image; positioning the scaled first image over the approximate location of the second image; generating a measure of fit between the first image and the second image; re-positioning the second image and repeating the above steps to obtain an increased measure of fit value.

Abstract: A method is provided for deriving an objective sharpness metric for objectively determining the level of image sharpness of many and unspecific images having different degrees of sharpness. The method for deriving the objective sharpness metric utilizes sub-band frequency information and false edge information for both an original video sequence and a sharpened sequence to be scored.

Abstract: A teletext data separation apparatus has a slice level generating circuit including a slice timing control circuit, a control register, an adder and a divider. The slice timing control circuit generates a timing signal for sampling. The control register carries out ON/OFF control of the slice timing control circuit. The control register sets by its register value the number of the sampling points of the adder and divider. By varying the register value in response to the reception state, the number of the sampling points can be increased from the specified 16 points, for example. This makes it possible for teletext data separation apparatus to generate an appropriate slice level that enables the teletext data to be separated reliably even in conditions where noise or distortion occurs in the video signal because of the effect of a weak electric field or ghost.

Abstract: A method of attenuating noise contained in an image signal according to the extent of the movement of the image signal based on the amount of noise, and an apparatus therefor are provided. This method includes measuring the amount of noise in an image signal by accumulating an offset between an input image signal and a delayed output image signal for a predetermined time, detecting the extent of the movement of the input signal based on the amount of noise measured, and forming an output image by controlling the specific weight of the input image signal and the delayed output image signal according to the detected movement.

Abstract: An OSD cursor display method and an OSD image display apparatus are provided, wherein an information that has an own cursor display data is transmitted from a display apparatus to an OSD source, and when said OSD source wants to transmit an OSD cursor to said display apparatus, it is checked whether said display apparatus has an own cursor display data, said OSD source transmits only cursor display location information if said display apparatus has the own cursor display data, and the own cursor display data is displayed at a received cursor display location. Therefore, since the OSD source only transmits cursor display location information to the display apparatus, the processing speed becomes faster, and therefore the location moving time in moving a cursor on a screen becomes faster and the movement of the cursor becomes smooth.

Abstract: An audio signal adjusting apparatus for adjusting raw audio signals to produce adjusted audio signals, comprises an audio signal adjusting unit for adjusting the raw audio signals and operably connected with loudspeakers for producing audio sounds that collectively originated from an imaginary sound source. The imaginary sound source is imagined to produce the audio sounds at a location spaced apart from each of the loudspeakers. A controlling unit allows each of the raw audio signals to be adjusted in response to a location control signal indicative of the location of the imaginary sound source. A pointer image producing unit produces a pointer image indicative of the location of the imaginary sound source. A superimposing unit is designed to superimpose the pointer image on a portion of a screen image after receiving a video signal from a video signal producing unit in response to the location control signal.