US5594758A

3G

Title

Frequency controller and method of correcting phase estimates in a PSK demodulator using frequency control

Family ID:

Application Date:

07-06-1995

Publication Country:

US

Priority Date:

31-12-1992

Declaring Company:

Abstract  Abstract

A digital demodulator and method for demodulating digital data representing a phase shift keyed (PSK) signal are provided. The demodulator comprises a phase detector automatic frequency controller automatic timing recovery controller data decoder and unique word detector. According to the method of the present invention a PSK signal is received and digitized to substantially remove the signals amplitude characteristics. The phase detector receives an input of the digital data and based upon transitions in the data from a high state to low state and from a low state to a high state provides phase estimates. The phase estimates are converted by the data decoder into binary data representing the symbols transmitted to form the PSK signal. A number of overlapping windows of digital data are used to determine phase estimates. The unique word detector receives an input of binary data from the data decoder and using a correlation technique identifies one set of windows which substantially maximizes synchronization of the demodulator with the received PSK signal. After the synchronizing window has been identified the automatic frequency controller monitors any frequency drift of the PSK signal and corrects the phase estimates based on the frequency error. The automatic timing recovery controller uses the corrected phase errors from early and late windows with respect to the synchronizing window to adjust the timing of the synchronizing window by advancing or delaying the demodulators symbol timing signal to further maximize synchronization with the received PSK signal.

Note:

The information in blue was extracted from the third parties (Standard Setting Organisation, Espacenet)

The information in grey was provided by the patent holder

The information in purple was extracted from the FrandAvenue

Explicitly disclosed patent:openly and comprehensibly describes all details of the invention in the patent document.

Implicitly disclosed patent:does not explicitly state certain aspects of the invention, but still allows for these to be inferred from the information provided.

Basis patent:The core patent in a family, outlining the fundamental invention from which related patents or applications originate.

Family member:related patents or applications that share a common priority or original filing.