Digital frequency correction
AssigneeInternational Business Machines Corporation
InventorsGottfried Andreas Goldrian, Thomas Anthony Gregg
Life of this patent
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Abstract
The basic idea comprised of the present invention is to decentralize the generation of time information without suffering from the cost disadvantages expectable due to use of prior art techniques necessary for synchronizing and correcting a plurality instead of only one or two of time suppliers caused by said decentralization. This is achieved by the approach not to readjust the oscillator(s), but, instead, to accept the inaccuracy of the physical device ‘oscillator’ but to measure its inaccuracy and to correct it with the aid of a continuos correction calculation which is advantageously done in a digital way under usage of ETS input information and system oscillator output information.
Claims12
A method for adjusting the phase of a pulsed high frequency output signal generated by a local high precision clock to the phase of a pulsed reference high frequency signal, the method comprising the steps of:
- comparing the pulse occurrences of said signal to that of said reference signal by measuring the actual deviation between the pulsed high frequency output signal to be adjusted and the reference signal through pulse counting over a predetermined duration;
- determining a resulting actual signal deviation based on said comparing;
- calculating a correction procedure based on the resulting signal deviation by generating a correction pulse of calculated duration and calculated repetition frequency based on the actual deviation;
- and
- implementing said correction procedure by applying said correction pulse to said pulsed high frequency output signal at appropriate times in order to adjust it.
A circuit usable for performing a method for adjusting the phase of a pulsed high frequency output signal generated by a local high precision clock comprising:
- a comparator for comparing the pulse occurrences of said signal to that of a reference signal by measuring the actual deviation between the pulsed high frequency output signal to be adjusted and said reference signal through pulse counting over a predetermined duration;
- a processing component for determining a resulting actual signal deviation based on the comparing;
- a calculating component for calculating a correction procedure by generating a correction pulse of calculated duration and calculated repetition frequency based on the actual deviation;
- and
- signal correction component for applying said correction pulse to said pulsed high frequency output signal at appropriate times in order to adjust it.
A computer system comprising an oscillator card comprising a circuit usable for performing a method for adjusting the phase of a pulsed high frequency output signal generated by a local high precision clock comprising:
- a comparator for comparing the pulse occurrences of said signal to that of a reference signal by measuring the actual deviation between the pulsed high frequency output signal to be adjusted and said reference signal through pulse counting over a predetermined duration;
- a processing component for determining a resulting signal deviation based on the comparing;
- a calculating component for calculating a correction procedure by generating a correction pulse of calculated duration and calculated repetition frequency based on the actual deviation;
- and
- signal correction component for applying said correction pulse to said pulsed high frequency output signal at appropriate times in order to adjust it.
A computer system adapted to perform a method for adjusting the phase of a pulsed high frequency output signal generated by a local high precision clock to the phase of a pulsed reference high frequency signal, the method comprising the steps of:
- comparing the pulse occurrences of said signal to that of said reference signal by measuring the actual deviation between the pulsed high frequency output signal to be adjusted and the reference signal through pulse counting over a predetermined duration;
- determining a resulting signal deviation based on said comparing;
- calculating a correction procedure based on the resulting signal deviation by generating a correction pulse of calculated duration and calculated repetition frequency based on the actual deviation;
- and
- implementing said correction procedure by applying said correction pulse to said pulsed high frequency output signal at appropriate times in order to adjust it.
An oscillator card comprising at least a part of a circuit usable for performing a method for adjusting the phase of a pulsed high frequency output signal generated by a local high precision clock comprising:
- a comparator for comparing the pulse occurrences of said signal to that of a reference signal by measuring the actual deviation between the pulsed high frequency output signal to be adjusted and said reference signal through pulse counting over a predetermined duration;
- a processing component for determining a resulting signal deviation based on the comparing;
- a calculating component for calculating a correction procedure by generating a correction pulse of calculated duration and calculated repetition frequency based on the actual deviation;
- and
- signal correction component for applying said correction pulse to said pulsed high frequency output signal at appropriate times in order to adjust it.
Dependencies are inferred from the claim text.