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. 09, 1997
Filed:
Jun. 07, 1995
John James Poklemba, Ijamsville, MD (US);
Comsat Corporation, Bethesda, MD (US);
Abstract
A sampling method, denoted continuously variable IF sampling (CVIFS), implemented in digital transmission and reception components is characterized by sampling a bandpass signal which is centered at an intermediate frequency f.sub.IF that is related to both the data transmission symbol rate (R.sub.s) and sample rate (NR.sub.s) by integer ratios. Moreover, the CVIFS method is characterized in that the sample rate NR.sub.s is constrained to be four times the IF center frequency, and both the sample rate NR.sub.s and the IF center frequency are constrained to be within a range of a factor of 1.5 of their maximum values. To maintain this high sample rate as the data symbol rate is lowered, a 'gear shifting' technique is utilized whereby the integer number of samples-per-symbol, N, is increased as the symbol rate decreases. Moreover, the sample rate NR.sub.s is always between 3.0 to 4.5 times the maximum data symbol rate (R.sub.smax), and the IF center frequency is always between 3/4 to 9/8 times (R.sub.smax), irrespective of the actual data rate R.sub.s.