Teledyne Lecroy, Inc.

Lecroy Corporation

Anirudh Kailash Sureka

Peter James Pupalaikis

Kaviyesh B Doshi

Roger Delbue

Francois Lamarche

Laxmikant Joshi

A method and apparatus are provided for calculating s-parameters of a device under test from step waveforms acquired by a time domain network analyzer.

Time domain reflectometry step to S-parameter conversion

An apparatus for measuring s-parameters using as few as one pulser and two samplers is described. The apparatus calibrates itself automatically using the internal calibration standards.

Time domain network analyzer

A non-linear digital filtering process is provided whereby slew rate limitation-like phenomena in analog circuitry are compensated. Particularly, a reduction of the signal amplitude with respect to the theoretical size of the signal if linearity had held is avoided. A correct phase is re-established. Customized linear filtering, up-sampling, and down-sampling before and after the non-linear digital processing minimizes the creation of harmonics. The inventive system and method for non-linear processing has few parameters and it is not limited to a polynomial series. A dedicated calibration method is also provided to adapt the value of the parameter for a precise compensation of the right amount of slew rate limitation or other similar compression. Furthermore, a calibration method is shown to adjust existing DSP filtering to accomplish a precise desired filtering even when non-linear corrections may be arbitrarily large.

Decompressor

A method and apparatus are provided for the removal of significant broad-band noise from waveforms acquired for time domain network analysis. The method may include the steps of providing the noisy waveform as an input waveform, determining a frequency domain noise shape associated with the input waveform, calculating a wavelet domain noise shape from the frequency domain noise shape, calculating a discrete wavelet transform of the input waveform to form a wavelet domain waveform, and estimating the noise statistics from the wavelet domain waveform. A threshold may be calculated from the estimated noise statistics and the wavelet domain noise shape, and the threshold may be applied to the wavelet domain waveform to form a denoised wavelet domain waveform. Finally, an inverse discrete wavelet transform of the denoised wavelet domain waveform may be calculated to form a denoised waveform.

Wavelet denoising for time-domain network analysis

A method of digitizing an analog signal is provided, comprising the steps of separating the analog signal spanning a frequency range into a plurality of frequency bands, and then translating at least one of the signals to a lower frequency band in accordance with a local oscillator and digitizing the at least one translated signal with digitizing elements having a frequency range less than the analog signal frequency range. A fixed relationship of the phase of the local oscillator and a repetitive signal generated in accordance with a writing to a circular buffer of the digitized representation of the at least one of the plurality of frequency bands is then defined. Signals corresponding to the other of the plurality of frequency bands are digitized and written to corresponding circular buffers. Finally, a digital representation of the analog signal is formed from the digitized signals.

Method and apparatus for a high bandwidth oscilloscope utilizing multiple channel digital bandwidth interleaving

A method and apparatus for generating a reflection filter. The method comprises the steps of determining an averaged step response of an acquired signal and generating a spectrum response from the averaged step response. A time at which a reflection in the averaged step response begins is determined and information in the averaged step response after the determined time when the reflection begins is replaced with an ideal flat line response to generate a required step response. A spectrum response is generated from the required step response and each frequency point of the spectrum response corresponding to the required step response is divided by each frequency point of the spectrum response corresponding to the averaged step response to generate a spectrum of the reflection filter. The result of the dividing step is processed to generate a reflection filter impulse response.

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Mamaroneck, NY, United States of America

Anirudh Kailash Sureka