초록 ▼

A method of developing waveforms having the energy therein concentrated within a limited bandwidth and modems for generating, transmitting, and receiving digital data utilizing such waveforms as carriers. A set of mutually orthogonal basis signals are selected to maximize their energies within the c

A method of developing waveforms having the energy therein concentrated within a limited bandwidth and modems for generating, transmitting, and receiving digital data utilizing such waveforms as carriers. A set of mutually orthogonal basis signals are selected to maximize their energies within the channel, each is binary coded and stored in the modem. A set of optimized coefficients is stored and utilized to weight each basis function in a coding arrangement to define bytes of digital data. The coded and weighted basis functions for each successive byte are summed to form a composite signal and transmitted over the channel as an analog waveform. Stored basis signals at the receiving end are correlated with the received waveform to thereby extract the coefficients which are decoded to reproduce the transmitted bytes. Both coding gain and reduction of intersymbol interference is achieved.

대표청구항 ▼

The method of transferring digital data over a bandwidth limited channel comprising the steps of: generating, at the transmitting end of the channel, a set of n mutually orthogonal equal length basis signals in which the energy of each of the basis signals within such limited bandwidth is maximized

The method of transferring digital data over a bandwidth limited channel comprising the steps of: generating, at the transmitting end of the channel, a set of n mutually orthogonal equal length basis signals in which the energy of each of the basis signals within such limited bandwidth is maximized and the length of the set represents a baud; storing the n basis signals in a selected order; generating a set of n coefficients in which the minimum difference energy between any pair of coefficients is maximized; storing a set of 21.5n code combinations of the n coefficients; designating a different one of said code combinations for each different one of the possible combinations of 1.5n bits; assembling successive bytes of 1.5n bits of digital data to be transmitted; selecting the designated code combination for each successive digital data byte; weighting the respective n stored basis signals of the set by the code combination for each successive byte; summing the n weighted basis signals for each byte to form successive composite signals representative of the successive data bytes; and transmitting the successive composite signals over the bandwidth limited channel at a selected baud rate.