Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Autonomous or machine generation of test specifications can be achieved by capturing the measured test data of a device and then using the captured test data to build a test specification, such as a limit line, for subsequent testing of similar devices. The generated test specification is typically adapted for use with respect to limited resources, such as through use of a piece-wise linear configuration. In an embodiment, the number of piece-wise linear portions of the generated test specification is minimized or otherwise optimized. In embodiments, the generated test specification is adjusted to accommodate expected measurement variation, such as thermal noise, device process variation, random jitter, etc., and, if desired, adjusted to allow for changes in test accuracy of subsequent tests. In one embodiment, one or more test measurement inaccuracies are eliminated in the construction of the limit line.

Abstract: 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.

Abstract: Staggered interleaved Nyquist regions associated with differing ADC clock rates (FCLK) 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 RB1 may be the First Nyquist region for a basic sampling frequency Fs. An adjacent raw band of operation RB2 that overlaps RB1 may be the Second Nyquist region for an alternate sampling frequency 2Fs/3. An adjacent raw band of operation RB3 that overlaps RB2 may be the Second Nyquist region for the basic sampling frequency Fs. These raw bands interleave and overlap: RB1: DC to Fs/2 1st Nyq. for FCLK = Fs RB2: (?)Fs ? (½)(?Fs) = Fs/3 to 2nd Nyq.

Abstract: Staggered interleaved Nyquist regions associated with differing ADC clock rates (FCLK) 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 RB1 may be the First Nyquist region for a basic sampling frequency Fs. An adjacent raw band of operation RB2 that overlaps RB1 may be the Second Nyquist region for an alternate sampling frequency 2Fs/3. An adjacent raw band of operation RB3 that overlaps RB2 may be the Second Nyquist region for the basic sampling frequency Fs. These raw bands interleave and overlap: RB1: DC to Fs/2 1st Nyq. for FCLK = Fs RB2: (2/3)Fs ? to 2(2Fs/3)/2 = 2nd Nyq.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A signal analyzer has an analysis scale and a display scale that are independently selectable. The signal analyzer receives a first representation of an applied signal and provides from the first representation at least two alternative representations. A first selective input enables a designated one of the alternative representations to be applied to a filter to reduce variance of the designated representation. The signal analyzer then converts the received one of the alternative representations having reduced variance to at least two alternative display scales. A second selective input enables a designated one of the alternative display scales to be displayed on a monitor, display screen or other output device of the measurement instrument or system.

Abstract: A mode selection method for signal analyzers having alternative swept and Fast Fourier Transform (FFT) modes of operation enables tradeoffs between measurement speed and dynamic range to be optimized in selecting between the alternative operating modes. The method includes setting the signal analyzer to either a manual state or an automatic state according to a first input to a user interface. When the manual state is set, the analyzer is operated in either the swept operating mode or the FFT operating mode according to a second input to the user interface. When the automatic measurement state is set, a third input to the user interface determines whether measurement speed or dynamic range is optimized. Measurement speed is optimized according to a first optimization scheme and dynamic range is optimized according to a second optimization scheme.

Abstract: An autoranging apparatus and method for an analog-to-digital converter (ADC) which uses a proposed gain detector including a peak of absolute detector and a quantizer to determine a proposed gain, and a amplifier gain setting rule processor in parallel with an anti-aliasing (AA) filter. The rule processor generates a current gain from inputs including the current gain, proposed gain, and a resolution bandwidth (RBW) value. The current gain is used to set a variable amplifier before the signal is sampled & held, and then converted to a digital word via the ADC. A variable bandpass filter can additionally be used before the AA filter to produce a pre-filtered signal. The pre-filtered signal would similarly be processed by the proposed gain detector. The resulting digital word is scaled down again through values stored in a look-up table. The look-up table is generated via a calibration routine which determines with certain precision the variable gain levels for the particular amplifier device used.