摘要:
A method of and apparatus for converting between first and second digital data formats is disclosed whereby digital words of the first format are analyzed to detect an upper bandwidth limit of a corresponding analog signal in an interval thereof defined by such words and to determine the level of the analog signal at the beginning of such interval. A digital word of the second format is encoded with first and second pluralities of bits representing the determined upper bandwidth limit and the level of the corresponding analog signal at the beginning of the interval.
摘要:
A method of and apparatus for converting between first and second digital data formats is disclosed whereby digital words of the first format are analyzed to detect an upper bandwidth limit of a corresponding analog signal in an interval thereof defined by such words and to determine the level of the analog signal at the beginning of such interval. A digital word of the second format is encoded with first and second pluralities of bits representing the determined upper bandwidth limit and the level of the corresponding analog signal at the beginning of the interval.
摘要:
There is disclosed herein a method of and system for reproducing an analog signal using digital techniques. The system includes means for encoding the analog signal in digital form and means for decoding the encoded analog signal. The encoding means includes means for detecting the upper bandwidth limit of the input analog signal during each of a plurality of successive sample intervals. Means coupled to the detecting means are included for sampling the input analog signal at a sampling rate determined in accordance with the detected upper bandwidth limits to derive a series of voltage levels which together define a sampled approximation of the input analog signal. Means are coupled to the sampling means for converting each voltage level and the sampling rate at which such voltage level was derived into digital signals. Also included are means for detecting when the input analog signal is at substantially a zero level, means for developing a digital indication of the length of time the signal is at such level and means for combining the digital indication with the digital signals to develop a digital representation of the input analog signal. The decoding means includes means for sequentially retrieving the digital signals, means coupled to the retrieving means for converting the digital signals into the sampled approximation of the input analog signal and a low-pass filter coupled to the converting means having a cut-off frequency determined in accordance with the encoded sampling rate for filtering the sampled approximation to reproduce the input analog signal.