Data insertion techniques for expanding information capacity of existing communication systems

摘要: Methods and apparatus are described for inserting data in a communications system, such as an existing analog using quadrature amplitude modulation (QAM) with in-phase signals signals. These methods can minimize the distortion to while maximizing signal strength. The may be sub-modulated on subcarrier frequency (201) that do not interfere detectors receivers, processed abatement filter (202) mitigate due Nyquist mismatch receiver. injection phase of determined (206) by adaptive algorithms, monitor receiver (103).