초록 ▼

A data compression method and appartus particularly suitable for use in electrical power line fault data recorders. The system performs both gain compression and frequency compression. For gain compression, a predetermined number of samples are analyzed to determine a gain setting common to each sam

A data compression method and appartus particularly suitable for use in electrical power line fault data recorders. The system performs both gain compression and frequency compression. For gain compression, a predetermined number of samples are analyzed to determine a gain setting common to each sample in the set of samples. A reduced data string consisting of a gain code and data words having fewer bits than the input words are transmitted as a compressed data string. For frequency compression, a sample set representing the input signal is decimated until there remain only a sufficient number of data samples to satisfy the Nyquist criterion for the highest frequency component of interest. Also included is a circuit for reproducing the waveform envelope. Positive and negative peak detectors provide signals representative of the peaks of the waveforms. These positive and negative signals are then compressed with the gain compression circuit, decompressed after transmission or recall, and then displayed as an envelope waveform for allowing trend analysis.

대표청구항 ▼

An electrical power line waveform envelope monitoring and display apparatus, comprising: means connectable to an electrical power line for sampling signals representative of the peaks of waveforms occurring on said electrical power line and for providing a plurality of digital samples; means for com

An electrical power line waveform envelope monitoring and display apparatus, comprising: means connectable to an electrical power line for sampling signals representative of the peaks of waveforms occurring on said electrical power line and for providing a plurality of digital samples; means for compressing said plurality of digital samples and for providing a compressed data set for transmission over a communication link; means for transmitting said compressed data set over said communication link; means for decompressing said compressed data set after transmission over said communication link and for providing a plurality of decompressed digital samples; and means for displaying an envelope waveform reconstructed from said decompressed digital samples corresponding to the envelope of signals occurring on said electrical power line.