Invention Grant
- Patent Title: Method and apparatus for high-speed data transfer employing self-synchronizing quadrature amplitude modulation
- Patent Title (中): 采用自同步正交幅度调制的高速数据传输方法和装置
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Application No.: US12715684Application Date: 2010-03-02
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Publication No.: US09571326B2Publication Date: 2017-02-14
- Inventor: Stephen M. Bench , Roger B. Shaffer
- Applicant: Stephen M. Bench , Roger B. Shaffer
- Applicant Address: US CA San Diego
- Assignee: SEESCAN, INC.
- Current Assignee: SEESCAN, INC.
- Current Assignee Address: US CA San Diego
- Agent Steven C. Tietsworth, Esq.
- Main IPC: H04N7/12
- IPC: H04N7/12 ; H04L27/36 ; H04L27/34 ; H04L27/38

Abstract:
A Quadrature Amplitude Modulation (QAM) method and apparatus including a QAM transmit modulator with at least one unbalanced mixer, which creates an asymmetric two-dimensional (2-D) QAM symbol constellation. The asymmetrical symbol constellation provides baseband symbol clock signal leakage sufficient to facilitate quick and simple baseband symbol clock recovery and signal channel compensation at the QAM receiver without significantly degrading the system bit-error rate (BER). While slightly degrading static BER, overall system performance is improved when considering baseband symbol clock recovery and received signal compensation for an imperfect signal channel. This allows QAM to be deployed in systems where QAM is otherwise prohibitively expensive and improves overall system performance for any existing QAM system application without additional bandwidth, cost or complexity.
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