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:
May. 08, 1984
Filed:
Jun. 02, 1981
Earl F Smith, Melbourne, FL (US);
Daniel D McRae, West Melbourne, FL (US);
Harris Corporation, Melbourne, FL (US);
Abstract
An auxiliary phase tracking subsystem for compensating for fast phase changes in an adaptive transversal filter obtains a measure, from the received signal, of channel phase variations and corrects the phase of each received sample in accordance with this phase measure. The channel tracking weights are used in conjunction with the known transmitted symbols and the data decisions to 'predict' the n received samples, PR.sub.i, for each frame. The average difference in phase, DP, between the predicted samples, PR.sub.i, and the actual received samples, R.sub.i, is then used to determine the phase correction for each received sample prior to using it for making estimates. The received samples, R.sub.0, R.sub.1, ------, R.sub.n-1, are then corrected to obtain the corrected samples, CR.sub.0, CR.sub.1, ------, CR.sub.n-1, as follows: ##EQU1## and K.sub.1 and K.sub.2 are constants. The result of this is to phase-correct each received sample by some constant phase, K.sub.1 DP, plus an additional correction which increases linearly with time during the frame. This latter correction is, in effect, a 'frequency offset' correction and when accumulated from frame-to-frame serves the function of doppler tracking as well as phase tracking.