摘要:
A method and system for sharing files between a group of computer systems. The file sharing system allows a group of computer systems to be defined. The files shared by a group are associated with a group folder. A group folder is represented by a folder created by the file system of each member of the group. The folder at each member contains a file for each file that is shared by the group. The files in the folder of a member may be actual files stored at that member, which contains the content of the shared file, or virtual files identifying the actual file that is stored at another member. When a member accesses a virtual file, the file sharing system detects the access and requests that the file owner provide a copy of the file to the accessing member on a peer-to-peer basis. Whenever a shared file is modified, the file owner sends updated metadata for that file to the other members of the group.
摘要:
A test signal is transmitted over a communication channel and the signal is received by a receiver. The temporal evolution of the test signal is represented in a matrix and the inverse of the test signal evolution matrix is stored in the receiver. Samples of the received signal and the test signal evolution matrix inverse are used to compute the channel impulse response, and the values of the channel impulse response set signal restoration filter coefficient values. The received signal is then restored by filtering.
摘要:
An architecture for a very large scale integrated (VLSI) implementation of a finite imprise response (FIR) digital filter having no multipliers and a coefficient space limited to powers of two. The filter structure includes a data bus, a coefficient bus and a sum-in bus to each coefficient tap. Each tap has a coefficient and control word register which is loaded during an initialization phase of the filter. Multiplication is provided by a shifter which provides the correct power of two weighting of an input data sample. The weighted data sample at each tap is added to the output of the previous tap. This architecture results in a regular, modular structure which can be cascaded and which is programmable for various data word lengths and coefficient spaces.
摘要:
A round off mechanism maintains a mean value of the operand while rounding twos complement binary data. Positive data values are incremented at the first discard bit prior to truncation of the discard bits, as are negative data values having a one within the most significant discard bit and at least one other discard bit. The discard bits are simply truncated for all other negative data values.
摘要:
A system for improved ghost cancellation for use in particular in television receivers. The system featuring a superior ghost cancellation reference (GCR) signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization which also exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals. The GCR signal is encoded a selected television line of an eight field sequence of lines however the polarity of the GCR signal is reversed selectively from field to field prior to inserting it in respective television lines. At a decoder or television receiver incorporating the invention, the selected television lines are combined in a manner which provides for both a robust received GCR value and cancellation of the effects of pair-wise constant television line signals on the GCR signals.
摘要:
An apparatus for receiving a television signal containing a ghost cancellation reference signal, and for using the reference signal to process the television signal so as to substantially eliminate path induced distortion.
摘要:
A system for improved echo cancellation for use in particular in television receivers. The system features a superior ghost cancellation reference signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization while exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals.
摘要:
A method and apparatus for improved ghost cancellation for use in particular in television receivers. The sequence of coefficients derived from a received GCR (Ghost Cancellation Reference) signal, is further processed to effect a transfer of energy from minor echo coefficients to major echo coefficients thereby improving the overall performance of the ghost cancellation device.
摘要:
A novel echo cancellation reference (“ECR”) training signal is inserted into the current ATSC 8 VSB data stream to achieve improved echo rejection while maintaining compatibility with the ATSC 8 VSB digital ATV standard. The novel ECR training signal is also suitable for other multipath or dispersive digital communication channels. A pre-equalization subsystem is included in the digital ATV system as a front end to the VSB receiver, and is trained with preferably the novel ECR training signal. One type of pre-equalization subsystem provides a fully ATSC compliant signal at its output, and therefore is particularly useful with standard VSB receivers. Another type of pre-equalization system provides a signal at its output which is ATSC compliant in some respects but which retains the ECR signal, and therefore is particularly useful for signal relays, analysis purposes, and other applications in which the residual channel information is important.
摘要:
A television receiver comprising a system for improved echo cancellation. The system features a superior ghost cancellation reference signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization whiel exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals.