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:
Oct. 20, 2009
Filed:
Jan. 17, 2007
Harald Sandner, Marzling, DE;
Harald Parzhuber, Eching-Haunwang, DE;
Harald Sandner, Marzling, DE;
Harald Parzhuber, Eching-Haunwang, DE;
Texas Instruments Deutschland GmbH, Freising, DE;
Abstract
An all digital PLL system generates an analog oscillator signal at intermediate frequencies to achieve averaged oscillator frequencies at an extremely high frequency resolution. The PLL system includes a digitally controlled oscillator () with a digital control input and an analog signal output, and a feedback loop with a digital loop filter () for generating a digital control signal for the digitally controlled oscillator (). The digital loop filter () has a first output providing an integer part (n) of the digital control signal and a second output providing a fractional part (n) of the digital control signal. A sigma-delta modulator () has an input connected to the second output of the digital loop filter () and an output providing a one-bit digital output signal (ΣΔ), and a digital adder () has a first input connected to the first output of the digital loop filter (), a second input connected to the output of the sigma-delta modulator (), and an output connected to the digital control input of the digitally controlled oscillator (). The output of the sigma-delta modulator () modulates the least significant bits from the first output of the digital loop filter ().