Pseudo-Random Binary Sequences and Data Scramblers
This experiment begins a series on digital communications. DSP technology has made a dramatic impact on digital communications, particularly narrow band systems like voice-band telephone line modems. In 1970, a plain 9600 bps telephone line modem was the size of a big microwave oven and cost at least $15,000. Today the signal processing portion of a state-of-the-art V.34 28,800 bps modem can be bought as a set of two or three chips for about $40 and the entire modem, which often includes an ordinary microprocessor controller, can be bought for less than $250. In addition, this modern modem has many more features, such as data compression, error detection and correction, trellis coded modulation, fax modes, automatic dialing, network management functions, a secondary channel, and the ability to do most of the past popular modem standards ranging from speeds of 300 bps up to 28800 bps. Because of the flexibility of the software approach to implementing signal processing algorithms with DSP’s, new theoretical developments have almost instantaneously been included in commercial telephone line modems. These techniques have later found their way into higher speed systems that use greater channel bandwidths, like high-speed digital subscriber loops and microwave systems.
KeywordsBinary Sequence Nonzero Coefficient Primitive Polynomial Maximal Length Sequence High Speed System
Unable to display preview. Download preview PDF.