Patent References 3517117 Logarithmic color matrix for a digital television receiver Data compression apparatus and method for encoding and decoding multi-line signals Video-optimized modulator-demodulator with adjacent modulating amplitudes matched to adjacent pixel gray values Suppressed double-sideband communication system Patent #: 4780884 InventorsAssigneeApplicationNo. 212549 filed on 06/28/1988US Classes:348/14.12, Transmission control (e.g., resolution or quality)358/469, Carrier wave modulation375/261, Quadrature amplitude modulation379/93.31ProtocolExaminersPrimary: Ng, Jin F.Assistant: Chan, Wing F. Attorney, Agent or FirmInternational ClassesH04M 011/00H04L 027/20 H04L 027/22 AbstractThe present invention assigns amplitudes of sine wave cycles in a data packet on I and Q channels of a QAM signal to color, gray or luminance values. Overlapping sine wave cycles on the I and Q channels in the data packet are assigned to the same or neighboring pixels. A synchronizing signal is sent at the beginning of each transmission of a packet. The synchronizing signal is a plurality of cycles at a maximum amplitude on the I and Q channels. The synchronizing signal serves two functions simultaneously. First, it is used to indicate the beginning of a new packet. Second, the phase of the synchronizing signal is used to initialize the demodulator phase detecting circuitry.Field of SearchCarrier wave modulation | |