Methods of Frequency versus Temperature Compensation of Existing Crystal Oscillators

• US 20110193600A1
• Filed: 01/31/2011
• Published: 08/11/2011
• Est. Priority Date: 02/01/2010
• Status: Active Grant

• Current Assignee: Tacettin Isik
• Original Assignee: Tacettin Isik
• Inventors: Isik, Tacettin
• Granted Patent: US 8,766,736 B2
• Time in Patent Office: Days
• US Class Current: 327/156
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H03L 1/027 by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/substract logic circuit H03L1/023, H03L1/026 take precedence
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/1974 for fractional frequency division
• CPC Class Codes: H03L 7/23 with pulse counters or frequency dividers

Abstract

Methods for compensating the existing crystal oscillator frequencies in extended temperature ranges. These are utilizing existing crystal oscillators on any system design which may have quartz crystals with associated circuitry to deliver frequency or timing reference signals. They are increasing these existing circuitry'"'"'s accuracy simply by adding small integrated circuit component.

Claims

1. A method of converting traditional and existing crystal oscillators into temperature compensated ones by adding a frequency temperature stabilization unit (FTSU) next to existing oscillators comprisingadjusting frequency by switching the load capacitors of the crystal oscillator in and outmeasuring temperature and adjusting the capacitor valuescontaining a linearization circuit to make temperature variation as flat as possiblehaving external load capacitors moved inside the unithaving a coarse frequency adjustment circuit interfaced to outsideproviding trimming capability to obtain flat “

frequency versus temperature”

behavior either during manufacturing or board building.

2. A method of converting traditional and existing VCXOs into temperature compensated ones by adding a frequency temperature stabilization unit (FTSU) that isbeing slow in response time not to interfere with VCXO control circuitrysetting the center frequency in such a way that center frequency does not drift by temperaturehaving a reference resonator and associated load capacitors packaged togetherhaving a frequency multiplier phase locked loop system to match with external oscillator'"'"'s nominal frequencyhaving yet another phase locked loop system to control external oscillator'"'"'s frequencyreceiving feedback signal from terminals of the external resonator unit to create the feedback path.

3. A method of converting traditional and existing crystal oscillators into temperature compensated ones by adding a frequency temperature stabilization unit (FTSU) which eliminates frequency multiplier PLL byintroducing a fractional divider which helps achieving similar frequency granularityresetting the capacitor switching circuit every fractional count cyclemaking internal oscillator frequency to be free runningmaking the frequency correction over temperature range using fractional divider programming.