Frequency shift offset quadrature modulation and demodulation
Offset QPSK demodulator and receiver
Zero-IF receiver wih feedback loop for suppressing interfering signals
Procedure and circuit for detection of the information of a received signal
Frequency demodulator for recovering digital signals Patent #: 4752742
ApplicationNo. 07/237535 filed on 08/29/1988
US Classes:375/328, Including switching or gating (digital circuits)329/303, Including logic element (e.g., logic gate or flip-flop375/334, Frequency shift keying375/340Particular pulse demodulator or detector
ExaminersPrimary: Safourek, Benedict V.
Assistant: Chin, Stephen
Attorney, Agent or Firm
International ClassesH04L 27/144 (20060101)
H04L 27/152 (20060101)
Foreign Application Priority Data1987-08-29 JP
AbstractAn FSK demodulation circuit which receives as input an FSK modulated reception signal, obtains two quadrature pulse trains, i.e., a first pulse train and a second pulse train, from a phase detection circuit, is provided with at least two sampling means which use the edge of one of the pulse trains and sample the logic of the other pulse train, produces two or more sample outputs at different timings, and determines the logic of the reproduced data from a combination of the logics "1" and "0" of the sample outputs.