The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 19, 1989
Filed:
May. 06, 1988
Keith A Chanroo, late of Parkland, FL (US);
Francis R Steel, deceased, late of Parkland, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A received phases modulated signal includes a plurality of information bits preceeded by three preamble bits. At periodic time intervals, approximately equal to one bit period, the receiver samples the signal and determines the phase angle of each bit at the sampling time. For the preamble bits, the receiver computes the phase error between the first and second preamble bits (A.sub.y -A.sub.x) and the phase error between the second and third preamble bits (A.sub.z -A.sub.y). An overall phase error (PE) is computed by taking the average of these two phase errors. To demodulate a DPSK signal, the average phase error (PE) is added to the phase angle (A.sub.i) of the present information bit. This adjusted phase angle (A.sub.i ') is then compared to the phase angle of the previous bit (A.sub.i -1) to demodulate the signal. To demodulate a PSK signal, the average phase error (PE) multiplied by D is added to the phase angle of the present information bit. This adjusted phase angle (A.sub.i ') is compared to the phase angle (A.sub.r) of a reference bit to demodulate the signal. D is the 'distance'; i.e., the number of bits between the present information bit and reference bit.