Agilent Technologies, Inc.

Keysight Technologies, Inc.

Hewlett-packard Company

Joseph Michael Gorin

Wing J Mar

Corydon Joseph Boyan

John Francis McLaughlin

Jochen Rivoir

George Stennis Moore

Matthew Johnson

Kenneth D Poulton

Daniel Lee Pleasant

Peter J Cain

Moray Denham Rumney

David H Molinari

David D Sharrit

Gordon Strachan

Michael E Barnard

Michael Ferrel

Douglas Gordon Yule, Jr

Roger D Sheppard

Duaine C Wood

Robert Locascio

Robert Nathan Nelson

Philip Ivan Stepanek

Thomas M Wright

John J Kuhn

Gregory B Korelich

Generally, in accordance with the various illustrative embodiments of the invention, a signal analyzer can incorporate a quasi-peak detection circuit that includes a detector diode. The detector diode is reverse-biased by using a direct-current (DC) voltage source. In some exemplary implementations, the DC bias voltage is defined on the basis of a predicted DC voltage at an output node of the quasi-peak detection circuit in response to a noise level contribution of the signal analyzer when the detector diode is unbiased. A signal is propagated through the quasi-peak detection circuit after the detector diode is reverse-biased, followed by a noise floor adjustment procedure. The noise floor adjustment procedure includes an adjustment directed at least in part, at compensating for the DC bias voltage that is used to reverse-bias the detector diode.

Quasi-peak detection systems and methods

In an exemplary embodiment of the disclosure, a signal analyzer includes at least one noise reduction system in the form of an adaptive noise reduction system. The adaptive noise reduction system executes an adaptive noise floor extension (NFE) procedure that includes determining a predicted standard deviation of a response by the signal analyzer to intrinsic noise in the signal analyzer when various signal processing parameters desired by a user are applied to an input signal. The predicted standard deviation is then used in the signal analyzer to select and apply various noise subtraction values upon the input signal before displaying of a signal spectrum of the input signal upon a display of the signal analyzer. The adaptive NFE procedure is directed at reducing or eliminating various ambiguities and/or errors in the displayed signal spectrum.

Adaptive noise reduction in a signal analyzer

Measurement systems and methods are provided for performing preselection to remove images and spurs from a signal being measured that automatically determines a threshold value that is used in the preselection algorithm. Using the automatically-determined threshold value in the preselection algorithm improves image and spur removal from the final trace that is displayed on the display device of the measurement system by trading off the risk of images or spurs being contained in the final trace against the average level of noise bias.

Systems and methods for removing images and spurs from measured radio frequency (RF) signals

An electromagnetic interference (EMI) signal is processed by digitizing the EMI signal, generating a plurality of overlapping time records from the digitized EMI signal, applying a window function to the plurality of overlapping time records to produce a plurality of modified time records, wherein the window function has a substantially flat top, and performing a fast Fourier transform (FFT) on each of the modified time records to produce a plurality of corresponding amplitude envelopes.

Overlapped fast fourier transform based measurements using flat-in-time windowing

A method is provided for aligning a measurement instrument that includes a tunable filter. The method includes: (i) applying an output signal of an internal noise source of the measurement instrument to the input of the tunable filter, (ii) applying a control signal to the tunable filter to tune the tunable filter to a selected alignment frequency, (iii) measuring a value for a gain alignment parameter of the tunable filter while the output signal of the internal noise source is applied to the input of the tunable filter and the control signal is applied to the tunable filter, (iv) storing the measured gain alignment parameter value in an alignment table in the memory device, and (v) repeating steps (ii) through (iv) for a plurality of selected alignment frequencies in an operating frequency range of the tunable filter.

Method of alignment for radio frequency measurement instrument and measurement instrument including same

An apparatus for measuring spectral components of a signal is described. The apparatus comprises a measurement acquisition unit configured to receive an input signal and to provide a measurement trace. The apparatus also comprises a model module configured to model one or more of a phase noise from the apparatus, a broadband noise from the apparatus, and a third order intermodulation (TOI) product from the apparatus. The apparatus also comprises a display configured to show one or more of the phase noise from the apparatus, the broadband noise from the apparatus, and the TOI product from the apparatus.

Spectrum analyzers with dynamic range indicator and methods of use

A measurement technique that provides a full solution to the gated local oscillator sweep measurement and improves the accuracy of signal analyzers in gated sweep mode by pre-sweeping the local oscillator at the beginning of a gate pulse and over-sweeping the local oscillator at the end of each gate pulse.

Gated sweep in spectrum analyzers

A synthetic test system for swept-frequency measurements that has a clock synchronization device to enable test boxes and devices that form the synthetic test system to have a common sense of time when conducting swept-frequency tests.

Swept-frequency measurements with improved speed using synthetic instruments

Staggered interleaved Nyquist regions associated with differing ADC clock rates (F) avoids spectrum lost through disjoint guard bands at the end of or between adjacent Nyquist regions. The staggered interleaved Nyquist regions overlap by an amount at least as much as is consumed by the guard bands. Selectable anti-aliasing filters associated with each Nyquist region and its ADC clock rate are used to enforce the staggered Nyquist regions and their various guard bands. For example, and neglecting guard bands, an initial raw band of operation RBmay be the First Nyquist region for a basic sampling frequency F. An adjacent raw band of operation RBthat overlaps RBmay be the Second Nyquist region for an alternate sampling frequency 2F/3. An adjacent raw band of operation RBthat overlaps RBmay be the Second Nyquist region for the basic sampling frequency F. These raw bands interleave and overlap: In this example the smallest overlap is F/6. We then select widths for guard bands that do not exceed F/6. Additional ADC clock rates and anti-aliasing filters may be used to operate in still higher Nyquist regions.

Staggered interleaved Nyquist regions avoid guard band induced holes when sampling a band limited signal

Using component-level test data to reduce system test. By modeling a system, sensitivity analysis reveals critical components and parameters of those components required to meet system performance parameters. Critical components are tested for these parameters, and these measurements associated with the components. Systems may be assembled which are modeled to meet the system performance parameters based on the model and the measured parameters. Systems may be assembled and calibration coefficients derived and applied from the model and the measured parameters.

Using component-level calibration data to reduce system-level test

A user interface for an electronic instrument includes a display that displays a signal and a band marker. The band marker demarks a bandwidth of the signal by marking both a start frequency of the bandwidth and a stop frequency of the bandwidth. The electronic instrument performs a function on the bandwidth of the signal between the start frequency and the stop frequency.

Markers used in the calculation and display of band functions

A system and method compensate for phase noise of a spectrum analyzer when measuring the phase noise of an applied signal based on an established model of the phase noise that accommodates a variety of operating states of the spectrum analyzer. Each operating state has a carrier frequency associated therewith. A frequency offset from the carrier frequency of a designated operating state identifies a frequency range for measuring the phase noise of the applied signal. The model, along with the frequency offset, is used to form an array that is applied to extract an output signal from a phase noise measurement signal that is acquired by the spectrum analyzer.

Phase noise compensation for phase noise measurements

A method and apparatus compensates for phase noise added by a spectrum analyzer from phase noise measurements of a signal under test (SUT) taken by the spectrum analyzer. The method comprises the steps of measuring the phase noise of the SUT, determining the added phase noise of the spectrum analyzer, and applying a mathematical correction to the measured phase noise. A spectrum analyzer apparatus that compensates for added phase noise comprises a controller portion, a memory portion, a signal conversion and detection portion, and a compensation algorithm stored in the memory portion. A system that compensates for added phase noise comprises a controller having a control algorithm and a spectrum analyzer. The compensation and control algorithms are computer programs that implement the method of the present invention.

Phase-noise measurement with compensation for phase noise contributed by spectrum analyzer

A system and method compensate for phase noise of a spectrum analyzer based on an established model of the phase noise that accommodates a variety of operating states of the spectrum analyzer. The model is used to form an array that is applied to extract an output signal from measurement traces that are acquired by the spectrum analyzer.

Phase noise compensation for spectral measurements

The present invention provides an RF spectrum measurement analyzer and method and more particularly to a GSM output RF spectrum measurement analyzer and corresponding method. One preferred embodiment of the present invention is applicable to GSM applications. However, other embodiments could be applicable to the general class of Time Division Multiple Access (TDMA) signals of which GSM, PDC (Pacific Digital Cellular), NADC and the like are a part. According to one preferred embodiment of the present invention, the method includes the steps of acquiring an RF carrier signal; converting the acquired RF carrier signal to an IF signal; converting the IF signal to a digital signal of relatively wide bandwidth; FFT filtering the digital signal to measure multiple offset frequencies within the IF bandwidth; and mathematically applying a resolution bandwidth filter at each offset. A further embodiment includes the steps of inverse FFT filtering the output of the resolution bandwidth filter and measuring the power in the time domain.

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Santa Rosa, CA, United States of America

Joseph Michael Gorin