Methods and apparatus for computing and using a spectral map for performing nonlinear calibration of a signal path
AssigneeAgilent Technologies, Inc.
InventorsNicholas B. Tufillaro, Robert E. Jewett
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Abstract
In one embodiment, a spectral map for performing nonlinear calibration of a signal path is developed by 1) identifying a set of frequency locations for a set of particular output signal spurs that result from applying one-tone and two-tone input signals covering a bandwidth of interest to the signal path; 2) developing, based on the set of frequency locations, a spectral map for predistorting, in the frequency domain, signals that are applied to, or received from, the signal path in the time domain; and 3) saving the spectral map for performing nonlinear calibration of the signal path.
Claims20
A method of developing a spectral map for performing nonlinear calibration of a signal path, comprising:
- identifying a set of frequency locations for a set of particular output signal spurs that result from applying one-tone and two-tone input signals covering a bandwidth of interest to the signal path;
- developing, based on the set of frequency locations, a spectral map for predistorting, in the frequency domain, signals that are applied to, or received from, the signal path in the time domain;
- and
- saving the spectral map for performing nonlinear calibration of the signal path.
A method of performing nonlinear calibration of a signal path, comprising:
- computing a discrete Fourier transform (DFT) of an input signal to the signal path;
- applying a spectral map to the DFT of the input signal, to generate a predistorted signal in the frequency domain, the spectral map being based on i) a set of frequency locations for a set of particular output signal spurs that result from applying one-tone and two-tone input signals covering a bandwidth of interest to the signal path, and ii) measured amplitudes and phases of single-tone spurs resulting from an application of one-tone input signals to the signal path;
- computing an inverse DFT (IDFT) of the predistorted signal in the frequency domain, to generate a predistorted signal in the time domain;
- and
- causing an arbitrary waveform generator of the signal path to launch the predistorted signal in the time domain via the signal path.
Apparatus for calibrating a signal path, comprising:
- an arbitrary waveform generator, coupled in an input-end of the signal path;
- and
- a distortion correction engine configured to,
- receive an input signal for the arbitrary waveform generator;
- compute a discrete Fourier transform (DFT) of the input signal;
- apply a spectral map to the DFT of the input signal, to generate a predistorted signal in the frequency domain, the spectral map being based on i) a set of frequency locations for a set of particular output signal spurs that result from applying one-tone and two-tone input signals covering a bandwidth of interest to the signal path, and ii) measured amplitudes and phases of single-tone spurs resulting from an application of one-tone input signals to the signal path;
- compute an inverse DFT (IDFT) of the predistorted signal in the frequency domain, to generate a predistorted signal in the time domain;
- and
- provide the predistorted signal in the time domain to the arbitrary waveform generator.
Dependencies are inferred from the claim text.