Digital Generation of Linearly Modulated Data Waveforms

A frequency domain analysis of the digital generation of linearly modulated data waveforms is presented. It is shown that for any rational relation of line carrier frequency and digit frequency, digital data transmitters can be designed economically and adapted to large scale integration (LSI) techniques. Special attention is given to the elimination of digital multipliers throughout the system. The results are illustrated with an example of an all-digital vestigialsideband (VSB) transmitter, with a specially shaped output spectrum which facilitates carrier and clock recovery in the receiver.