Method of differential-phase/absolute-amplitude polar qam
AssigneeHoneywell Federal Manufacturing & Technologies, LLC
InventorJEFFREY DIMSDLE
Life of this patent
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Abstract
A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.
Claims13
A method of amplitude scale tracking to substantially reduce scale variations in a received quadrature amplitude modulated signal, the method comprising the steps of:
- (a) determining an amplitude ratio of two or more consecutive sampled amplitude values;
- (b) determining whether the amplitude ratio represents a valid transition;
- (c) identifying, for a determined valid transition, one or more ideal amplitude levels corresponding to one or more sampled amplitude values of the valid amplitude transition;
- (d) determining a scale factor value based upon the ideal amplitude level and the corresponding sampled amplitude level;
- and
- (e) using the scaling factor value to scale and compensate for any changes in strength of the received quadrature amplitude modulated signal.
A method of amplitude scale tracking to substantially reduce scale variations in a received quadrature amplitude modulated signal, the method comprising the steps of:
- (a) determining an amplitude ratio of two consecutive sampled amplitude values, wherein each of the two consecutive sampled amplitude values is approximately equal to √((I value)2+(Q value)2);
- (b) determining whether the amplitude ratio represents a valid transition as being within a pre-established tolerance of a nominal amplitude ratio;
- (c) identifying, for a determined valid transition, one or more ideal amplitude levels corresponding to one or more sampled amplitude values of the valid amplitude transition;
- (d) determining a scale factor value based upon the ideal amplitude level and the corresponding sampled amplitude level;
- and
- (e) determining an I value and a Q value corresponding to the identified consecutive sampled amplitude values;
- and
- (f) multiplying the I value and the Q value by the scaling factor value to compensate for any changes in strength of the received quadrature amplitude modulated signal.
Dependencies are inferred from the claim text.