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:
Apr. 01, 2008
Filed:
Sep. 09, 2004
Philip E. Quinlan, County Cork, IE;
Kenneth J. Mulvaney, County Sligo, IE;
Patrick G. Crowley, County Limerick, IE;
William Hunt, County Limerick, IE;
Philip E. Quinlan, County Cork, IE;
Kenneth J. Mulvaney, County Sligo, IE;
Patrick G. Crowley, County Limerick, IE;
William Hunt, County Limerick, IE;
Analog Devices, Inc., Norwood, MA (US);
Abstract
A digital frequency measurement system including first and second digital differentiators responsive to first and second digital quadrature signals representative of first and second quadrature modulated input signals that represent binary data having a center frequency equal to a predetermined IF frequency for generating first and second differentiated signals, first and second processing circuits responsive to the first and second digital quadrature signals representative of the modulated input signals and the first and second differentiated signals for multiplying the first differentiated signal by the second quadrature digital representation of the input signals and multiplying the second differentiated signal by the first quadrature digital representation of the input signals to provide first and second multiplied signals, a combining circuit responsive to the first and second multiplied signals for generating a density signal having a pulse density proportional to the frequency of the input signals, a digital filter responsive to the density signal for providing an output signal representing the average value of the pulse density, and an envelope detector circuit responsive to the output signal for determining the midpoint of the maximum and minimum signal level representative of the input signals and providing a digital signal that represents the center frequency of the input signals.