Wavecrest Corporation

Other

Megatest Corporation

Gigamax Technologies, Inc.

Jan Brian Wilstrup

Peng T Li

Dennis M Petrich

Mark J Emineth

Christopher Kimsal

Ross Adam Jessen

Steven H Ulsund

Steven J Fraasch

John David Hamre

Steven John McCoy

Mike Peng Li

Stanley P Mros

Steve McCoy

Russell E Cook, Jr

Chris Kimsal

Jie Sun

A method and system for removing the effect of intersymbol interference (ISI) from a data record indicating times of logic level transitions exhibited by a data signal that has been distorted by ISI exhibited by a system having a particular step response may perform the following acts. The data record may be received, and a transition from within the data may be selected record for removal of ISI. Preceding transitions within the data record are then inspected. A time defect is obtained, based at least in part upon the inspected preceding transitions. Finally, the data record is adjusted, based upon the time defect, to indicate a new time of transition for the selected transition, thereby removing the effect of ISI for the selected transition.

Waveform analyzer

A clock recovery system includes a rough clock generator, which yields a rough clock signal, based upon logic level transitions exhibited by a data signal. The rough clock signal is supplied to a phase locked loop having an adjustable order of frequency response, an adjustable corner frequency, an adjustable natural frequency, and/or an adjustable damping factor. The clock recovery system includes control parameters that, when properly adjusted, suppress non-ideal effects of components within the clock recovery system, and also permit the frequency response of the phase locked loop to be returned to a desired response.

Method and apparatus for clock recovery

A method, apparatus, and article of manufacture for analyzing a measurable distribution having random components and deterministic components. The method includes the steps of collecting data, constructing a probability density function based on the data such that the probability density function is a convolution of deterministic functions and random functions, constructing a probability density function based on a deterministic and random convolution model having three or more parameters wherein at least one of the parameters are unknown, and determining unknown parameters by using a deconvolution process.

Method and apparatus for analyzing a distribution

A system for determining a response characteristic of an nth order linear system, such as a phase locked loop, is disclosed. An input signal is supplied to the linear system, and the system measures an output signal produced by the linear system. A variance record is constructed for a measurable quantity, such as jitter, extracted from the output signal. The response characteristic of the linear system is then obtained from the variance record. The response characteristic, such as the transfer function, noise processes, and/or power spectral density (PSD), may be found through a numerical or analytical solution to a mathematical relationship between a response function of the nth order linear system and the variance record.

Method and apparatus for determining system response characteristics

A method, apparatus, and article of manufacture for analyzing measurements. The invention provides a method for separating and analyzing the components of a distribution, such as deterministic and random components. The method performs the steps of collecting data from a measurement apparatus, constructing a histogram based on the data such that the histogram defines a distribution, fitting tails regions wherein deterministic and random components and associated statistical confidence levels are estimated.

Method and apparatus for analyzing measurements

A system is disclosed for precisely measuring time intervals, used to either characterize or diminish noise components in repetitive waveforms. An interval timer generates a whole number count of cycles in combination with beginning and ending ramps capable of resolving fractions of a cycle, to accurately register the time interval. Selection logic can be implemented to time either single periods or spans of multiple consecutive periods of the waveforms. Multiple time measurements are arranged in sets, each set corresponding to a different span of &ldquo;N&rdquo; consecutive periods over a range of values for N. A variance of each set is generated, and an array of variance vs N provides a function having properties of an auto-correlation function. Instrument jitter can be reduced based on measurements of period spans rather than individual periods, and is reduced in proportion to the increasing size of the measured span. These techniques are enhanced by random statistical samples, obtained by a dithering of the measurement rate. This also diminishes the impact of aliasing products.

Analysis of noise in repetitive waveforms

An event counter circuit including an input signal coupled to a frequency divider circuit that can be cleared by an external signal, a multiplexer coupled to the divider circuit driven by an output edge and its inverse, and a counter circuit coupled to the multiplexer driven by outputs of the multiplexer.

Measurement system with a frequency-dividing edge counter

A method, apparatus, and article of manufacture for separating the components of a jitter signal. The method includes the steps of obtaining measurements of the spans of a signal, generating variation measurements for each of the spans, transforming the variation estimates from a time domain to a frequency domain, and determining the random component and the periodic component of the jitter signal.

Method and apparatus for jitter analysis

A linear ramp generating and control circuit finding particular applicability in a time interval measurement system. The linear ramp circuit includes a hold capacitor which may be linearly discharged during one operating mode of the circuit by coupling a constant current source to the capacitor. The voltage on the hold capacitor is linearly discharged away from a baseline voltage level to a data voltage level which is subsequently passed to an analog-to-digital converter of the time interval measurement system for further processing. The hold capacitor voltage is returned to the baseline voltage level during a recovery mode of circuit operation by a recovery or recharge network. The recharge network may include an active-feedback circuit which implements an approximately second-order voltage response to the hold capacitor during the recovery mode of operation. The circuit may also include a composite amplifier for buffering the hold capacitor voltage level to a circuit output during a hold mode of circuit operation. The effect of this invention is that the errors such as drift, signal noise, and baseline voltage instability can be minimized.

Time interval measurement system incorporating a linear ramp generation circuit

A power supply for testing an integrated circuit includes a source voltage input terminal for receiving an input voltage. The power supply serves as both a DUT active power supply and an IDDQ measurement circuit, without the need for switching between separate DUT active power supply and IDDQ measurement circuits. In one embodiment, a current source output driver includes a diode across a current sensing resistor inside a feedback loop. This minimizes VDD changes when the DUT demands transient current, such as when loading IDDQ test vectors. Moreover, with decreased transient changes in VDD, dielectric absorption effects of a decoupling capacitor are reduced.

Growing community of inventors

Mounds View, MN, United States of America

Jan Brian Wilstrup