Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – Frequency of cyclic current or voltage
Reexamination Certificate
2005-11-29
2005-11-29
Oda, Christine (Department: 2858)
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
Frequency of cyclic current or voltage
C324S076520
Reexamination Certificate
active
06969984
ABSTRACT:
The present invention, generally speaking, provides a time shift angle demodulator that is of simple construction and has an extended linear range. Range extension is achieved by using the input signals directly, not simply post-processing the S-PFD outputs. In accordance with one embodiment of the invention, a method of measuring the phase or frequency of a periodic input signal uses a periodic reference signal and includes comparing the input signal to the reference signal to obtain a lead signal and a lag signal; changing the count of an up/down counter in dependence on the input signal, the reference signal, the lead signal and the lag signal; and using the lead signal, the lag signal and the count signal to produce a phase or frequency signal. In accordance with another embodiment of the invention, an apparatus for measuring the phase or frequency of a periodic input signal uses a periodic reference signal and includes a comparison circuit for comparing the input signal to the reference signal to obtain a lead signal and a lag signal; a logic circuit, including an up/down counter, responsive to the input signal, the reference signal, the lead signal and the lag signal to change the count of the up/down counter; and circuitry for using the lead signal, the lag signal and the count signal to produce a phase or frequency signal.
REFERENCES:
patent: 5220293 (1993-06-01), Rogers
patent: 6021157 (2000-02-01), Kanterakis et al.
patent: 6075410 (2000-06-01), Wildhagen
patent: 6104762 (2000-08-01), Fujimura
patent: 6107848 (2000-08-01), Pickering et al.
patent: 6163209 (2000-12-01), Myers
patent: 2002/0000800 (2002-01-01), Hill
Benson Walter
Oda Christine
Tropian Inc.
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