Method and system for simultaneously broadcasting and receiving digital and analog signals
AssigneeUSA Digital Radio Partners, L.P.
InventorsBill J. Hunsinger, Derek D. Kumar
Life of this patent
Estimating the term…
Abstract
Apparatus and method for transmitting a digitized wideband signal robust to multipath degradation and intersymbol interference within a predetermined broadcast band. A basis set of wideband mutually orthogonal pseudorandom basis signal waveforms of substantially equal length and having predetermined autocorrelation values and a predetermined spectral shape are generated. The length of the waveforms in the set represents a baud. The wideband waveforms of the basis set are data modulated so as to define digital data. The basis set substantially maintains the predetermined spectral shape during the modulation.
Claims19
A method of simultaneously transmitting an analog FM signal and a digitized wideband signal robust to multipath degradation and intersymbol interference within a predetermined broadcast band, the method comprising the steps of:
- a) producing the analog FM signal substantially centered about a center frequency of a predetermined broadcast band;
- b) generating a basis set of wideband mutually orthogonal pseudorandom basis signal waveforms of substantially equal length and having predetermined autocorrelation values and a predetermined spectral shape, the length of the waveforms in the set representing a baud, said predetermined spectral shape of the basis waveforms in the basis set including two spaced apart sections, one on each side of the center frequency;
- c) data modulating the wideband waveforms of the basis set so as to define digital data, the basis set substantially maintaining said predetermined spectral shape during said modulation;
- d) linearly combining the analog FM signal and the modulated waveforms to produce a composite signal;
- and
- e) transmitting the composite signal through atmospheric free-space to at least one receiver.
A transmitter for broadcasting a signal including an analog FM signal portion and a digital signal portion robust to multipath degradation, the transmitter comprising:
- means for generating the analog FM signal substantially centered about the center frequency of a predetermined broadcast band;
- means for generating a basis wideband set of substantially orthogonal spectrally shaped pseudorandom waveforms having predetermined autocorrelation properties, the basis waveforms being spectrally shaped so as to define a first portion on one side of the center frequency within the broadcast band and a second portion on an opposite side of the center frequency within the broadcast band so that the analog FM signal may be disposed substantially between the first and second portions of the spectrally shaped waveforms;
- modulation means for digitally modulating the basis set of spectrally shaped substantially orthogonal wideband waveforms to define the digital signals, the modulated waveforms maintaining their spectral shaping through the modulation;
- means for combining the analog FM and digital signals to form a composite signal;
- and
- broadcast means for transmitting the composite signal to at least one receiver.
A method for implementing a high spectral efficiency digital communication link in channels with known colored interference and multipath, the method comprising the steps of:
- a) determining the spectral content of the known colored interference;
- b) generating a basis set of wideband mutually orthogonal sequences, said sequences having predetermined autocorrelation characteristics;
- c) spectrally shaping said basis set to complement the colored interference;
- d) setting the baud interval, or length of said sequences, to a value greater than a determined longest expected multipath delay;
- e) data modulating said sequences;
- and
- f) transmitting said modulated sequences as waveforms over the digital communication link from a transmitter to a receiver.
A method of transmitting a digitized wideband signal robust to multipath degradation and intersymbol interference within a predetermined broadcast band, the method comprising:
- generating a basis set of wideband mutually orthogonal pseudorandom basis signal waveforms of substantially equal length and having predetermined autocorrelation values and a predetermined spectral shape, the length of the waveforms in the set representing a baud, the waveforms comprise codes having more than two values, the generating the basis set includes
- a) generating a plurality of random number wideband pseudorandom sequences via a plurality of samples,
- b) spectrally shaping each of the generated pseudorandom sequences into the first and second portions disposed on opposite sides of the center frequency,
- c) arranging the shaped pseudorandom sequences as columns of a matrix, the matrix having a greater number of rows than columns, and
- d) decomposing the matrix by singular value decomposition into the product of three additional matrices, wherein a substantial number of the columns of one of the additional matrices represents the basis wideband set of spectrally shaped waveforms;
- and
- data modulating the wideband waveforms of the basis set so as to define digital data, the basis set substantially maintaining said predetermined spectral shape during said modulation.
Dependencies are inferred from the claim text.