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.

Date of Patent:
Dec. 14, 1993

Filed:

Jul. 16, 1992
Applicant:
Inventors:

Juha Rapeli, Oulu, FI;

Timo Rahkonen, Oulu, FI;

Juha Kostamovaara, Oulu, FI;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03D / ;
U.S. Cl.
CPC ...
329341 ; 329342 ; 329343 ; 329345 ; 375 82 ; 375 94 ;
Abstract

An FM or PM signal is demodulated so that the cycle time of the modulated input signal is measured using a time-to-digital converter comprising a counter that uses a moderate clock frequency as a reference clock, a digital delay line interpolator and a control circuitry. The counter is used for rough digitization and the delay line for interpolating the moment of zero-crossing inside a clock cycle. Total delay of the delay line, i.e., the range of time intervals the interpolator is able to measure, is actively kept equal to the cycle time of the reference clock. When the number of delay elements in the delay line is a power of two, the result of the delay line interpolator may be used directly as the least significant bits of the measurement.


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