Communications: electrical – Continuously variable indicating – With meter reading
Reexamination Certificate
2007-01-02
2007-01-02
La, Anh V. (Department: 2612)
Communications: electrical
Continuously variable indicating
With meter reading
C340S003200, C340S536000, C341S061000, C375S356000, C348S497000
Reexamination Certificate
active
11088446
ABSTRACT:
A method and apparatus for maintaining an ideal frequency ratio between numerically-controlled frequency sources provides a mechanism for maintaining coherence between multiple synchronization references where a known ideal rational relationship between the sources is known. Multiple numerically controlled oscillators (NCOs) generate the multiple synchronization references, which may be clock signals or numeric phase representations and the outputs of the NCOs are compared with a ratiometric frequency comparator that determines whether there is an error in the ratio between the NCO outputs. The frequency of one of the NCOs is then adjusted with a frequency correction factor provided by the ratiometric frequency comparator. The NCO inputs can represent ratios of the synchronization reference frequencies to a fixed reference clock and the NCOs clocked by the fixed reference clock.
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Chowdhury Ahsan
Gudmunson Daniel
Melanson John
Singh Rahul
Cirrus Logic Inc.
Harris Andrew M.
La Anh V.
Mitch Harris Atty at Law, LLC
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