Digital modulation employing single sideband with suppressed carrier
OwnerHarold Walkerinventor
Life of this patent
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Abstract
A method for transmitting "biphase" encoded digital signals including the steps of setting an aperture corresponding to a data bit; dividing said aperture into a plurality of segments; setting a first segment, selected from said plurality of segments of said aperture, dependent upon whether the bit is a digital one or zero; setting a second segment, selected from said plurality of segments of said aperture, so as to fit the remaining aperture of the data bit; and, transmitting said first and second segments of said data bit; wherein a narrow spectrum results containing no low frequency components and separated from 0 Hz by an amount equal to the data rate or 1/2 the data rate.
Claims31
An encoding method for digital baseband signals comprising the steps of:
- dividing a data bit, having a bit center, into a plurality of time segments or apertures;
- selecting a first subset, from said plurality of apertures, ending prior to said bit center;
- and,
- selecting a second subset, from said remaining plurality of apertures, which ends after said bit center.
A digital transmission comprising the steps of:
- aperture encoding a digital baseband signal, said aperture encoding comprising:
- dividing a data bit, having a bit center, into a plurality of time segments or apertures;
- selecting a first subset, from said plurality of apertures, ending prior to said bit center;
- and, selecting a second subset, from said remaining plurality of time segments, which ends after said bit center;
- frequency modulating a signal responsively to said aperture coded data;
- and,
- receiving and detecting said modulated data using suitable receiving means.
An apparatus for use with digital signals comprising:
- means for aperture coding a source signal;
- means for transmitting said aperture coded source signal;
- means for detecting and receiving said aperture coded source signal;
- and,
- means for decoding said aperture coded source signal;
- wherein said aperture coding includes:
- dividing a data bit, having a bit center, into a plurality of apertures;
- selecting a first subset, from said plurality of apertures ending close to said bit center;
- and, selecting a second subset, from said remaining plurality of apertures, which starts after said first subset.
An encoding method for generating a digital baseband signal derived from a multiplicity of input data bits, wherein each data bit is characterized by a temporal data bit length having a temporal bit center, said encoding method comprising:
- receiving one of said multiplicity of input data bits;
- generating an encoded digital baseband signal corresponding in timing to said one input data bit which changes digital state according to said one input data bit in correspondence to a time prior to or after said temporal bit center.
A digital data and additional information transmission method comprising:
- encoding digital data using an aperture coding method comprising dividing a data bit, having a bit center, into a plurality of time segments or apertures;
- selecting a first subset from said plurality of apertures, ending close to said bit center;
- and, selecting a second subset of apertures, from said remaining plurality of time apertures, which ends after said bit center;
- wherein said coding method results in a narrow Fourier spectrum containing no low frequency components and is offset from 0 Hz by a quantity equal to the data rate;
- transmitting the aperture coded data utilizing phase or frequency shift modulation;
- and,
- receiving and detecting the transmitted signals using suitable receiving means.
Dependencies are inferred from the claim text.