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:
Feb. 12, 1985
Filed:
Jun. 25, 1982
U.S. Philips Corporation, New York, NY (US);
Abstract
A frequency-modulated input signal is converted at an adequately high sampling rate into a time-discrete and amplitude-discrete digital signal. This digital signal is applied to a simple transversal filter, having a sloping amplitude characteristic, more specifically having a sin.sup.2 transfer function and a constant group delay time, and to a delay device having a time delay which is equal to the group delay time. The output signal of the filter is applied to a numerator input of a divider (6) and the output signal of the delay device to a denominator input the divider (6) whose quotient contains the frequency corresponding to the amplitude characteristic of the filter. In this manner, a frequency demodulator having a very good AM-suppression and an adequate linearity at broad-band-FM is realized. The divider is formed, in accordance with the 'pipeline principle', from a plurality of identically constructed sections corresponding to the number of bit positions of the processed digital signals. As a result thereof a sufficiently high processing speed can be accomplished with very little cost. A correction circuit is provided to avoid faults and inaccuracies, respectively, in the case of small denominators.