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Title:
SYSTEM AND METHOD FOR REDUCING TEMPERATURE-DEPENDENT AND PROCESS-DEPENDENT FREQUENCY VARIATION OF CRYSTAL OSCILLATOR CIRCUIT
Document Type and Number:
Japanese Patent JP2013017176
Kind Code:
A
Abstract:

To provide an oscillator which compensates for temperature-dependent processing variations of a resonator, in an oscillator of a wireless communication element.

An oscillator 210 includes a resonator 310 in parallel with an active element 312. The resonator is coupled to a variable capacitor 314 having a variable capacitance, attaining output frequency tuning of the oscillator. A predetermined temperature compensation calculator 324 references characterization data to be performed to a lot of the resonator on the basis of a temperature signal received from a temperature sensor 322 and outputs a temperature-based frequency compensation signal. In addition, on the basis of the frequency estimation signal from a frequency estimator 326, a process compensation calculator 328 calculates a process-dependent compensation of the resonator, and outputs a process-based compensation signal. A multiplier 330, on the basis of the frequency compensation signal and the compensation signal, outputs a multiplier output signal. A control module 332, on the basis of the multiplier output signal, provides a control signal to the variable capacitor to compensate for temperature-based and process-based variations in the resonator.


Inventors:
DAVID HARNISCHFEGER
Application Number:
JP2012149427A
Publication Date:
January 24, 2013
Filing Date:
July 03, 2012
Export Citation:
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Assignee:
FUJITSU SEMICONDUCTOR LTD
International Classes:
H03B5/32; H03L1/02
Domestic Patent References:
JP2002290151A2002-10-04
JP2005277776A2005-10-06
JP2006191585A2006-07-20
JP2008066906A2008-03-21
JP2010500830A2010-01-07
JPH1065447A1998-03-06
JPH1065447A1998-03-06
JP2002290151A2002-10-04
JP2005277776A2005-10-06
JP2006191585A2006-07-20
JP2008066906A2008-03-21
JP2010500830A2010-01-07
JP2006506832A2006-02-23
Foreign References:
WO2003073629A12003-09-04
Attorney, Agent or Firm:
Tadashige Ito
Tadahiko Ito
Akinori Yamaguchi



 
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