Method and apparatus for digital shaping of a digital data stream

Claim 1

Digital waveform shaping apparatus for generating a desired digital data stream composed of a plurality of digital bits comprising: clock means for generating clock signals; storage means, coupled to the clock means and having an output, for storing bits of the desired digital data stream and for serially shifting the digital data stream bits to the output; detecting means, coupled to the storage means, for detecting the bit values and the transitions between adjacent bits of the digital data stream at the output of the storage means; generating means, responsive to the clock means, for generating a sequence of binary coded digital words corresponding to the magnitude of a sequence of samples of a gradual waveform; control means, coupled to the clock means, detecting means, and generating means, for controlling the generating means such that said sequence of binary coded digital words corresponding to a predetermined rising portion of said gradual waveform are generated in response to a rising transition in the digital data stream, said sequence of binary coded digital words corresponding to a predetermined falling portion of said gradual waveform are generated in response to a falling transition, a digital word corresponding to a constant high level is generated after said predetermined rising portion until the beginning of the generation of a falling portion, and a digital word corresponding to a constant low level is generated after said predetermined falling portion until the beginning of the generation of a rising portion; clock control means, coupled to the clock and the generating means, and the detecting means, for passing the clock signal to the generating means during generation of the predetermined rising or falling waveform portions, and for blocking the clock signal from the generating means during the generation of constant high or low levels converter means, coupled to the generating means, for converting the sequence of digital words to an analog waveform representative of the digital data stream; and, filter means, coupled to the converter means, for smoothing the analog waveform.