Sequential quadrant demodulation of digitally modulated radio signals
OwnerChristopher L. Anderson, Jeffrey W. Marshall +1inventors
InventorsChristopher L. Anderson, Jeffrey W. Marshall, Greg Casavant
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Abstract
This invention relates generally to a system and method for extracting data from a modulated signal, and more particularly to a system and method of demodulating constant-amplitude/continuous-phase digital radio modulated signals in a radio receiver. The data symbols are detected by establishing a complex trajectory of the modulated signal and interpreting the direction of the trajectory of the modulated signal as the digital data symbols. The invention has particular application to FSK-type modulated signals and more generally to π/n modulated signals.
Claims72
A method of demodulating a modulated signal containing digital data symbols comprising:
- a) establishing a complex trajectory of the modulated signal;
- and
- b) interpreting said complex trajectory of the modulated signal as said digital data symbols.
A method of demodulating a radio signal modulated with digital data symbols comprising:
- a) producing at least one in-phase (I) and quadrature (Q) pair from said signal;
- and
- b) interpreting said I and Q pair to detect said data symbols.
A method of demodulating a radio signal modulated with digital data symbols comprising:
- a) establishing the trajectory of the modulated signal in the complex plane;
- b) determining a first point on said trajectory at a first time;
- c) determining a second point on said trajectory at a second time later than said first time;
- d) comparing said first and second points;
- e) interpreting the difference in said points as a digital data symbol.
A system for extracting digital data symbols from a modulated signal comprising:
- a) a demodulator producing at least one in-phase (I) and quadrature (Q) pair from said signal;
- and
- b) a signal processor for interpreting said at least one I and Q pair to detect said digital data symbols.
A system for demodulating a radio signal modulated with digital data symbols comprising:
- a) a demodulator establishing a trajectory of the modulated signal in the complex plane;
- and
- b) a signal processor, said signal processor being operable to:
- i) determine a first point on said trajectory at a first time;
- ii) determine a second point on said trajectory at a second time later than said first time;
- iii) compare said first and second points;
- and
- iv) interpret the difference in said points as a digital data symbol.
A demodulation system for demodulating a digital radio signal with digital data symbols comprising:
- a) a demodulator producing an in-phase (I) and quadrature (Q) pair from said signal;
- and
- b) a signal processor for interpreting said I and Q pair to detect the digital data symbols.
A wireless receiver comprising:
- a) an antenna for receiving radio signals modulated with digital data symbols;
- b) a demodulator connected to said antenna for producing from said signal an in-phase (I) and quadrature (Q) pair;
- c) a signal processor for determining the direction of the trajectory of said in-phase (I) and quadrature (Q) pair and for associating a predetermined direction of the trajectory as a associated with a digital data symbol;
- and
- d) a circuit for outputting the digital data symbols.
A wireless receiver comprising:
- a) an antenna for receiving radio signals modulated with digital data symbols;
- b) a demodulator connected to said antenna for producing from said signal an in-phase (I) and quadrature (Q) pair;
- c) a signal processor for interpreting said I and Q pair to detect said digital data symbols;
- and
- d) a circuit for outputting the digital data signals.
A wireless receiver comprising:
- a) an antenna for receiving radio signals modulated with digital data symbols;
- b) a demodulator connected to said antenna for establishing a trajectory of the modulated signal in the complex plane;
- and
- c) a signal processor, said signal processor being operable to:
- i) determine a first point on said trajectory at a first time;
- ii) determine a second point on said trajectory at a second time later than said first time;
- iii) compare said first and second points;
- and
- iv) interpret the difference in said points as a digital data symbol.
A system for demodulating signals modulated with data symbols comprising:
- a) means for defining the modulated signal as a trajectory in the complex plane;
- b) means for sampling a plurality of points on said trajectory;
- c) means for comparing said points;
- and
- d) means for interpreting the results of said comparison as the data symbols.
Dependencies are inferred from the claim text.