Method and apparatus for transient frequency distortion compensation
AssigneeAtheros Communications, Inc.
InventorsPaul J. Husted, Bevan M. Baas
Life of this patent
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Abstract
Transient distortion is compensated for by multiplying an exponentially-decaying phase shift onto the distorted waveform. The exponentially decaying phase shift waveform is patterned after the transient which typically takes the form of an exponential and occurs upon introduction of power to a circuit or circuit component. A digital circuit produces an appropriate exponentially-decaying waveform which is used as the input for a look up table whose output is a complex sinusoidal waveform capable of compensating for the distortion. The complex sinusoid is multiplied onto the transmitted waveform. The decaying exponential is biased so that it crosses a threshold at which point the compensating circuitry is turned off.
Claims23
A method of compensating for transient distortions of a time-varying, information-bearing signal, the method comprising:
- identifying a distortion of the time-varying, information-bearing signal;
- generating a compensation waveform corresponding to the distortion;
- and
- applying the compensation waveform to the time-varying, information-bearing signal for a limited time,
- wherein said time-varying, information-bearing signal is a signal to be transmitted by a wireless communication device.
A method of compensating for transient distortions of a time-varying, information-bearing signal, the method comprising:
- identifying a distortion of the time-varying, information-bearing signal, wherein identifying includes identifying a signal transmission disturbed by start-up of a device that uses power;
- generating a compensation waveform corresponding to the distortion;
- and
- applying the compensation waveform to the time-varying, information-bearing signal for a limited time,
- wherein said time-varying, information-bearing signal is a signal to be transmitted, wherein generating the compensation waveform includes:
- identifying time increments from power up of the device;
- and
- at each time increment,
- performing a table lookup to determine a time increment compensation value;
- and
- applying the time increment compensation value to a corresponding part of the compensation waveform.
An apparatus for compensating for transient distortions of a signal, the apparatus comprising:
- a distortion compensating device configured to produce a compensation signal having a phase shift magnitude approximately equivalent to a magnitude of a frequency distortion occurring on a signal being transmitted, the signal being a time-varying, information-bearing signal;
- and
- a compensation multiplier configured to multiply the compensation signal onto the signal being transmitted for a limited time during transient distortion correction and configured to multiply other signals during channel correction.
Dependencies are inferred from the claim text.