Patent ID: 7253671
Filing Date: 2007-08-07
Classification: G01V,H03K,H04J

Abstract:
1. A method for compensating for frequency drift in a downhole system clock, comprising the steps of: providing a downhole clock system comprising an oscillator which generates pulss subject to a drift in frequency due to downhole environmental changes; sending pulses from the oscillator to a prescaler and a trigger module; comparing time pulses from the prescaler with a surface clock in a time base logic module and generating error values by the time base logic module; outputting the error values to the trigger module; recieveing error values from the time-base logic module by the trigger module; providing divisors to the prescaler by the trigger module sending signals at calculated intervals depending on the frequency drift to a compensator module which which sends a valve into the prescaler; and outputting by the prescaler corrected time pulses based off of the divisors provided by the trigger and compensator module.