Abstract:
A hierarchical threshold tree-based broadcast encryption method includes a first step for a server initialization and a user subscription, a second step of distributing a message to enable a privileged user (authorized user) to decrypt a group key, and a third step of the privileged user (authorized user) decrypting the message using the group key. According to the method, it is possible to prevent any group of revocators from obtaining the group key using their secret information and information being broadcast by the server.
Abstract:
A symbol timing recovery apparatus used with a VSB-type receiver and a method of the same. In order for the symbol timing recovery, error information is generated and used utilizing a band edge component maximization (BECM) of a frequency band as well as an upper frequency band. Therefore, the symbol timing recovery can be more effectively achieved even when the upper frequency band is damaged due to multi-path components. Also, efficiency of the overall timing recovery can be improved by using the lower frequency band as well as the upper frequency band of the received signal in performing the symbol timing recovery. As a result, deterioration of the receiving system including the symbol timing recovery apparatus can be prevented.
Abstract:
A digital broadcast transmission system and a signal processing method thereof offers improved receptability. The digital broadcast transmission system includes an error correction encoding unit for encoding an input signal according to a predetermined error correction method; a synchronous signal inserting unit for inserting a synchronous signal in the input signal after the error correction encoding; a first pilot inserting unit for inserting a first pilot signal in the input signal which contains the synchronous signal therein; a second pilot inserting unit for inserting a plurality of second pilot signals in the input signal which contains the first pilot signal therein; a pulse shaping filter for pulse shaping the input signal with the first and the second pilot signals according to a predetermined roll-off factor; and a radio frequency (RF) unit for transmitting the pulse-shaped input signal to a transmission channel band. By inserting a plurality of pilot signals in the transmitted data, problems associated with disappearance of only pilot signal due to poor channel environment can be overcome.
Abstract:
An apparatus to detect a sync signal, a VSB receiver using the same, and a method thereof. The apparatus includes a plurality of partial correlators to calculate a first partial correlation value between a sub sequence of a training sequence and an “I” signal of a received signal that corresponds to a range of a sub sequence and a second partial correlation value between the sub sequence of the training sequence and a “Q” signal of the received signal, and calculating the first partial correlation value and the second partial correlation value for each of the predetermined number of sub sequences, a plurality of squarers to square the first and second partial correlation values for each sub sequence, respectively, a plurality of adders to add the squared first and second partial correlation values for each sub sequence and add the added squared partial correlation values of all the sub sequences to provide a correlation signal between the training sequence and a corresponding portion of the received signal, a maximum value detection unit to detect a maximum one of the added partial correlation values of the sub sequences from the correlation signal, and a position detection unit to detect a position of the detected maximum value as the sync signal of the received signal.
Abstract:
A sync signal detecting apparatus, a method thereof, and a Vestigial Side Band receiver employing the apparatus. The apparatus includes a correlator to compute one or more correlation values of the received signal, a starting point determiner to detect a location of a received signal having a maximum correlation value within an arbitrary period, and to determine a location a predetermined interval from the detected location as a starting point, a main signal detector to determine a signal having a value obtained by multiplying one of the correlation values by a predetermined number that is larger than the maximum correlation value as a main signal among signals during the arbitrary period, and a location detector to detect and provide a location of the main signal to the equalizer. Accordingly, performance of an equalizer can be maximized by determining the main signal variably according to characteristics of the equalizer.
Abstract:
The present invention relates to a display apparatus including an input unit receiving a digital image signal and an analog image signal, a first storage unit storing digital display identification data, a second storage unit storing analog display identification data, a switching unit connecting the first storage unit or the second storage unit to the input unit, and a control unit controlling the switching unit so that display identification data having a priority is output through the input unit when the analog image signal and the digital image signal are simultaneously received.
Abstract:
A symbol timing recovery apparatus used with a VSB-type receiver and a method of the same. In order for the symbol timing recovery, error information is generated and used utilizing a band edge component maximization (BECM) of a frequency band as well as an upper frequency band. Therefore, the symbol timing recovery can be more effectively achieved even when the upper frequency band is damaged due to multi-path components. Also, efficiency of the overall timing recovery can be improved by using the lower frequency band as well as the upper frequency band of the received signal in performing the symbol timing recovery. As a result, deterioration of the receiving system including the symbol timing recovery apparatus can be prevented.
Abstract:
A carrier recovery apparatus usable with a VSB receiver and a method thereof. The carrier recovery apparatus is capable of recovering a carrier even though a pilot signal may be corrupted due to multi-path characteristics of a channel. Accordingly, the carrier recovery apparatus performs a BECM (Band Edge Component Maximization) algorithm on upper and lower sidebands of a received signal to generate phase information therefrom. The phase information is combined in a combiner. Since the BECM algorithm is performed on the upper and lower sidebands, it is possible to execute the carrier recovery even through the upper sideband of a received signal may be corrupted. Therefore, the carrier recovery apparatus can prevent performance degradation of the VSB receiver caused by corruption in the pilot signal.
Abstract:
A display device having a display to display a picture thereon, a power supply to supply power to the display, and a parameter setter to set a predetermined adjustment parameter. The display further includes one shared key and a controller. The controller can receive a push input signal from the sheared key, divide a duration time of the push input signal into a plurality of duration time sections, and control the power supply and the parameter setter to turn on/off the display device when the push input signal belongs to a first duration time section, to implement a parameter setting mode when the push input signal belongs to a second duration time section, and to implement a parameter executing mode when the push input signal belongs to a third duration time section. With this configuration, a display device in which only one key operation is enough to control a power supplying system and various adjustment parameters can be set as desired is provided.
Abstract:
A network scan apparatus includes: a scanner including a scanning unit to scan a document and generate an image file based on the scanned document, a transmitting unit to transmit the image file, and an output selection unit to select whether to output scan file information; an output device, connected to the scanner, via a network, to output the scan file information according to whether the scan file information is selected to be output after a scanning operation; and a host computer connected to the scanner and the output device via the network, to collect the scan file information transmitted from the scanner, and transmit the scan file information to the output device.