Abstract: A noise receiver is included in a network analyzer block diagram such that noise power and S-parameters measurements can be made almost simultaneously without mechanical switching in the test set. Additionally, a variable mismatch device tuner that is used by the network analyzer for S-parameter calibrations, is further used during the noise figure measurements method to remove the effect of source match variations so that the expected noise figure performance of the DUT when connected to a desired input (probably 50 ohms) can be determined.

Abstract: An integrated circuit arrangement has a signal input 20 and a signal output 60, a signal processing unit 100 which is connected to the signal input 20 and to the signal output 60, a noise source 50 for generating a noise signal, and a noise line 55 which connects the noise source 50 to the signal input 20.

Abstract: There is provided a jitter amplifier for amplifying or attenuating a jitter component contained in an input signal, having a jitter demodulating section for demodulating the jitter component from the input signal and an amplifying circuit for amplifying or attenuating the jitter component by controlling phase of the input signal based on the jitter component.

Abstract: A system analyzer may generate an estimated frequency response of a device, system, communication medium, or combination thereof by utilizing a stimulus signal that is robust against IQ modulator impairments. A stimulus generator may be used to generate a plurality of discrete tones according to a frequency spacing and a frequency offset. The frequency spacing and the frequency offset cause spectrally inverted spurs (generated by impairments of the IQ modulator) to occur at frequencies other than frequencies of said modulated signal that are associated with said plurality of discrete tones. Additionally, by implementing a Discrete Fourier Transform (DFT) to possess a frequency resolution equal to the frequency offset, there is no leakage of power associated with the spectrally inverted spurs into frequency bins of the DFT associated with the desired frequency components. Likewise, leakage between the desired frequency components and leakage associated with the local oscillator may be avoided.

Abstract: A mechanism for measuring noise densities below the noise floor of a measuring instrument. The measuring instrument may first acquire a fully-averaged reference spectral noise density trace and estimate corresponding reference statistical parameters. Based on the reference statistical parameters, the measuring instrument may construct a reference spectral noise density distribution. The measuring instrument may also acquire a fully-averaged sum spectral noise density trace and estimate corresponding sum statistical parameters. Based on the sum statistical parameters, the measuring instrument may construct a sum spectral noise density distribution. The measuring instrument may extract a spectral noise density distribution from the reference and sum distributions. The measuring instrument may also determine a confidence interval based on a desired confidence level.

Abstract: A method of testing for power and ground continuity of a semiconductor device having Input and Output (IO) pins and at least a pair of power and ground pins includes identifying the power and ground pins of the device. A victim pin is selected from the IO pins of the device for each pair of the power and ground pins, and an aggressor pin for each victim pin is selected from the remaining IO pins. The aggressor pins are toggled between a high state and a low state. A level of switching noise on each victim pin is measured, and the measured levels of switching noise are compared with predetermined data to determine power and ground continuity of the device.

Abstract: An improved method for determining whether a measurement point, measured using a differential absorption LIDAR (DIAL) system, represents a plume point or a non-plume point. Concentration path lengths (CPL's) for a plurality of measurement points are determined. An average non-plume CPL, CPL, is provided. For each measurement point, a standard deviation, CPLsd, is calculated based on first order error propagation and it is determined that the measurement point represents a non-plume point when the Hooshmand decision rule (HDR) is met. The HDR is given by, ( cpl - CPL _ CPL sd ) 2 > ( T ) 2 , where cpl is the corresponding CPL of the measurement point being tested and T is a threshold standard deviation level.

Abstract: A calibration structure for probing devices.

Abstract: A multi-sensor data fusion system and method provides adaptive weighting of the contributions from a plurality of sensors in the system using an additive calculation of a sensor reliability function for each sensor. During a predetermined tracking period, data is received from each individual sensor in the system and a sensor reliability function is determined for each sensor based on the SNR (signal-to-noise ratio) for the received data from each sensor. Each sensor reliability function is individually weighted based on the SNR for each sensor and a comparison of predetermined sensor operation characteristics for each sensor and a best performing (most reliable) sensor. Additive calculations are performed on the sensor reliability functions to produce both an absolute and a relative reliability function which provide a confidence level for the multi-sensor system relating to the correct classification (recognition) of targets and decoys.

Abstract: 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.

Abstract: Noise power is measured within one or more designated frequency bands of an applied signal. The measurement includes frequency translating the applied signal by a set of equally spaced frequencies to form a corresponding set of intermediate frequency signals, measuring the noise in at least two measurement bands of each of the intermediate frequency signals that are separated by the frequency spacing of the equally spaced frequencies, and determining the noise power in the designated frequency band of the applied signal based on the noise measurements.

Abstract: Methods of improving a signal to noise ratio using synchronous rejection are enclosed. Also disclosed are various synchronous rejection systems. In one method of synchronous rejection, the method includes correlating a phase of a reference signal to a phase of the interference signal; collecting a first data set during a first period of time using the reference signal; inverting the reference signal and re-correlating the phase of the reference signal to the phase of the interference signal; collecting a second data set during a second period of time using the inverted reference signal; and integrating the first and the second data set.

Abstract: An apparatus for the determination of the magnitude of a noise (TDUT) of an electronic object to be measured (2) includes a sine signal source (1), which generates a sine signal (Sin) for input into said object to be measured (2) and a level meter (3) for the measurement of a power level at the output of the said object to be measured (2). In accord with the invention, the level meter (3) possesses a sine power detector device (31) for the capture of a sine power level ({circumflex over (P)}sin) and has a noise power level detector device (32) for a separate capture of a noise power level ({circumflex over (P)}noise).

Abstract: A multi-sensor data fusion system and method provide an additive fusion technique including a modified belief function (algorithm) to adaptively weight the contributions from a plurality of sensors in the system and to produce multiple reliability terms including reliability terms associated with noise for low SNR situations. During a predetermined tracking period, data is received from each individual sensor in the system and a predetermined algorithm is performed to generate sensor reliability functions for each sensor based on each sensor SNR using at least one additional reliability factor associated with noise. Each sensor reliability function may be individually weighted based on the SNR for each sensor and other factors. Additive calculations are performed on the reliability functions to produce at least one system reliability function which provides a confidence level for the multi-sensor system relating to the correct classification (recognition) of desired objects (e.g., targets and decoys).

Abstract: Methods of improving a signal to noise ratio using synchronous rejection are enclosed. Also disclosed are various synchronous rejection systems. In one method of synchronous rejection, the method includes correlating a phase of a reference signal to a phase of the interference signal; collecting a first data set during a first period of time using the reference signal; inverting the reference signal and re-correlating the phase of the reference signal to the phase of the interference signal; collecting a second data set during a second period of time using the inverted reference signal; and integrating the first and the second data set.

Abstract: An apparatus and method are described for producing a test signal with a desired signal-to-noise ratio on a selectable output frequency for measuring a transmission system. A carrier signal, generated from a carrier signal, and a noise signal are remixed with the carrier signal in a bandwidth equal to or smaller than a smallest signal bandwidth of the transmission system. The levels of the carrier signal and the noise signal are adjusted to a predetermined ratio based on a measurement of the remixed carrier signal and the remixed noise signal. The noise signal is attenuated and added to the carrier signal until the desired signal-to-noise ratio is attained.

Abstract: Accordingly, the invention relates to a process and a device for measuring the attenuation of a line where the measurement process according to the invention makes it possible to measure the attenuation of a line at a given frequency F and includes at least the steps wherein the emission of an electric signal at one end of the electric line, provides a signal that includes a spectral amplitude A1 at the frequency F; the measurement of the signal reflected by the other end of the line, at the end of the line from where the signal was emitted; the determination of the amplitude A2 of the spectral component at the frequency F of the reflected signal; the determination of the attenuation of the line from the ratio of the amplitude A2 to the amplitude A1 where it applies in particular to the rating of asymmetric digital subscriber lines.

Abstract: A fault and noise tolerant system and method for obtaining an original signal which is not influenced by a fault or noise occurring in an electronic equipment. The fault and noise tolerant system includes a first estimation filter for estimating an original signal from a signal output from the electronic equipment, considering noise of the electronic equipment; a second estimation filter for estimating the original signal and a fault signal from the signal output from the electronic equipment, considering a fault and the noise; a fault detection unit for detecting the presence or absence of a fault in the electronic equipment based on the estimated fault signal received from the second estimation filter; and a selection unit for selecting one of the estimated original signals from the first and second estimation filters, respectively, according to the result of detection of the fault detection unit.

Abstract: An apparatus and method for detecting the presence of a valid signal includes an offset generator coupled to a pair of data slicers and an XOR gate. The offset generator is configured to both add and subtract a predetermined voltage to an input voltage in its two outputs. The two outputs of the offset generator are both compared to a predetermined value in a pair of data slicers. If the outputs of the data slicers are the same (i.e., either both offset signals are positive or both are negative), then a valid signal is indicated.

Abstract: A cable line quality evaluating method for evaluating a quality of a cable line for transmitting a digital modulation signal in a bidirectional manner comprises the steps of extracting a noise signal of an upstream line from one of a cable line connection point for evaluating a head end of the cable line evaluated in the quantity and the cable line evaluated in the quantity and a connection point between a tap-off and the cable line evaluated in the quality, generating a pseudo random signal, modulating a carrier signal of its predetermined frequency by means of the pseudo random signal, and then outputting the modulated signal as a test carrier, outputting an output signal obtained by adding the noise signal of the upstream line and the test carrier, selectively receiving the signal of its predetermined frequency from the output signal, and modulating the selectively received signal, and comparing the modulated signal with the pseudo random signal in bits, and then measuring a bit error rate.

Abstract: In order to check an occurrence of a signal component in an input signal, a method and a device is provided. The method comprises the steps of generating a measure for the frequency of the input signal from the input signal, determining a variance of the measure for the frequency of the input signal, comparing the determined variance with a predetermined limit value, and confirming the occurrence of the signal components if the variance lies within a predetermined range in relation to the predetermined limit value. The occurrence of a signal component in an input signal can be determined very fast and by performing only a few steps. Therefore, the method according to the invention and the device according to the invention can very well be used in particular in mobile devices, as for example in hearing devices.

Abstract: An apparatus for signal amplitude restoration has a received signal input and a scaled received signal output. An amplitude correction factor generator has an estimated signal-to-noise power ratio input and a received signal input. A variable gain amplifier uses the correction factor generator output to control its gain, and amplifies or attenuates the received signal input to provide the scaled received signal output. An average SNR estimator uses the amplifier output as its input, and provides an output connected to the estimated signal-to-noise power ratio input. The apparatus processes received signals in an iterative fashion, such that at least one of the outputs is stored for use as a feedback input during later iterations.

Abstract: An apparatus for determining signal quality on an outlet of a powerline network includes a powerline modem connected to a power outlet of a powerline network for sending and receiving a signal across the powerline network, and a signal quality indicator coupled to said powerline modem network for indicating signal quality received from another powerline modem coupled to the powerline network.

Abstract: In order to check an occurrence of a signal component in an input signal, a method and a device is provided.

Abstract: A method for measuring bioelectric impedance in real time, in the presence of interference and noise is disclosed. A small electric current is injected into a biopotential electrode system, and then the measurement is tested for contamination by electrical interference or other noise sources.

Abstract: Configurable interconnect resources of field programmable gate arrays (FPGA's) are tested by configuring at least some of the lookup tables (LUT's), registers and input signal acquirers to implement one or more sequential state machines that feed back their current states via at least some of the interconnect conductors to the inputs of the LUT's. The fedback signals are decoded by the LUT's for defining next-states of the one or more sequential state machines. Each sequential state machine may be programmed to sequentially step through a number of unique states, where the unique states challenge capabilities of the interconnect conductors to toggle through combinations of different signal levels. The sequential state machines are exercised to sequentially step through plural ones of their unique states.

Abstract: The present invention is a system and method of use for a computer-implemented signal-to-noise-ratio (SNR) estimation process for aiding in signal demodulation and message recovery or as an indication of recovered message fidelity. The SNR estimator produces estimates of the true channel SNR and tracks changes in the channel noise power over time. It operates on a collection of received data probability density functions (PDFs), either contained in closed form equations or stored in lookup tables. It allows for the estimation of both the instantaneous and average signal-to-noise ratio (SNR) values.

Abstract: An apparatus and method for detecting the presence of a valid signal includes an offset generator coupled to a pair of data slicers and an XOR gate. The offset generator is configured to both add and subtract a predetermined voltage to an input voltage in its two outputs. The two outputs of the offset generator are both compared to a predetermined value in a pair of data slicers. If the outputs of the data slicers are the same (i.e., either both offset signals are positive or both are negative), then a valid signal is indicated.

Abstract: A module for use in automatic test equipment is disclosed. The module is especially useful for performing power measurements on high frequency devices. The module includes a power sensor and a plurality of EEPROM's that store reflection coefficient data for the power sensor. Computerized control circuitry in the automatic test equipment uses the stored data to reduce impedance mismatch uncertainties in the power measurements.

Abstract: An S/N ratio of a probe current is measured while a filament current is changed, and the filament current in which the S/N ratio is maximal is determined.

Abstract: A measurement signal generating circuit for a linear scale capable of increasing an S/N ratio of a signal for measurement of a linear scale. A photo detector or a low-pass filter for removing noise entering the measurement signal generating circuit is arranged rearwardly of each of an A phase signal generating circuit and a B phase signal generating circuit. Such construction permits a noise component at a different phase as well as that at the same phase to be effectively removed during synthesis of the measurement signal, to thereby reduce an error in measuring by the linear scale.

Abstract: A module for use in automatic test equipment is disclosed. The module is especially useful for measuring noise parameters of high frequency devices. The module includes a noise generator and a plurality of EEPROM's that store reflection coefficients and ENR data for the noise generator. Computerized control circuitry in the automatic test equipment uses the stored data to reduce impedance mismatch and Excess Noise Ratio (ENR) data uncertainties in the measured noise parameters.

Abstract: A measuring device and method use a spectrum analyzer. The spectrum analyzer comprises a display screen controlled by a processor on which a spectrum of an input signal is displayed in a frequency region on a half portion of the display screen and a noise level at a frequency associated with the input signal is displayed in a time region on another half portion of the display screen.

Abstract: Noise factor of a radio-frequency device under test (DUT) is determined by driving the input of the DUT with a randomly modulated sine wave and measuring the power of a resulting DUT OUTPUT signal within each of a set of equally-sized frequency bands. The noise factor is computed as a combination of the power of the modulated sine wave within each of a plurality of frequency bands and the measured power of the DUT OUTPUT signal within that same plurality of frequency bands.

Abstract: A noise detecting and recording apparatus which can be widely used for countermeasures against malfunction of electronic equipment which is caused by noises is provided. The apparatus is provided with a unit for outputting data corresponding to the level of a conduction noise, a unit for outputting the data corresponding to the level of a radiation electromagnetic field noise, a unit for outputting the data corresponding to the level of a discharge noise, a temperature and humidity detection unit for detecting temperature and humidity and outputting the data corresponding to the detected value, a microcomputer for processing the output data from each unit, a display unit for displaying the output data, and a recording device for recording data, wherein the microcomputer performs the processing of receiving the output data from each unit and supplying the data to the display unit, and the processing of receiving the output data from each unit and recording the data in the recording device.

Abstract: Method and apparatus for non-invasive testing of digital communications systems. Amplitude measurements are made for multiple frequencies of a multi-frequency communication system, converted to the time domain. An adaptive filter output is matched to the time domain representation to characterize the channel. Impedance mismatches may be precisely located using this technique. An error signal representing a difference between a signal transmitted through the channel and a received signal is estimated and analyzed. The error signal is separated into components corresponding to contributions by wide band noise, residual phase modulation, and residual amplitude modulation. Identification and removal of narrow-band interferers may occur prior to this separation. Bit error rate and system margin computations employ a Monte Carlo simulation of the various error sources. This provides a well refined estimate of bit error rate and system margin.

Abstract: A high sensitivity multiple waveform voltammetric method and instrument are provided for use in electrochemical and other applications. The method consists of applying one or several variable potential excitation signals between electrodes of an electrochemical cell to produce an electrochemical reaction in the solution. The excitation signals include a DC bias potential increasing cyclically by a potential step to form a potential staircase signal sweeping across a potential domain, and a number of pulse trains either of opposite polarity or shifted in potential per potential step. An electric current derived from a diffusion flux of ions through the solution is measured as a result of the applied excitation signal.

Abstract: One method of determining the signal to noise ratio of an optical signal models the noise floor based on amplified spontaneous emission (ASE) which is accumulated along the link. The ASE wavelength dependence is represented by a known mathematical function with a limited number of parameters. The parameters of this function are derived from measurements of the noise floor at a limited number of points by computational best fit means. A number of fiber grating filters at wavelengths between ITU allocated wavelengths are used to sample the optical noise and reflect the light back. An optical circulator is used to direct the reflected ASE light to an optical switch which allows the detector to select between transmitted and reflected light. The signal transmitted through the switch is monitored by a scanning filter with the appropriate resolution to resolve the signal or noise peaks. A first scan of the transmitted peaks is carried out and the signal is digitized and stored.

Abstract: A delay time of a delay time generating circuit which delays an inputted pulse signal for a predetermined time and outputs the delayed pulse signal is measured. A random pulse generating circuit for outputting a train of pulses at random intervals is provided, and an output signal of the delay time generating circuit is applied to an input signal thereof through a positive feedback loop. An output signal is applied from the random pulse generating circuit to the positive feedback loop to cause the positive feedback loop to oscillate, and a delay time of the delay time generating circuit is determined from a period at which the positive feedback loop oscillates. The delay time can accurately be measured without being affected by an interference caused by another signal or a disturbance brought about by noise.

Abstract: A measurement system and method for a telecommunication systems diagnoses problems within a communication line. The measurements are performed both non-intrusively and intrusively in an interactive manner, and evaluate the transmission quality of the communication line through to the subscriber's telephone set.

Abstract: Analog and mixed signal integrated circuits are tested using the modified Volterra series to model the integrated circuit being tested. An adaptive algorithm, for example, least mean square or Kalman, is used to determine to coefficients of the Volterra series. The coefficients are then used to calculate the THD and SNR.

Abstract: An analog test probe includes an integrated circuit having a large number of separate channels, each connected to one of its inputs. There is a plurality of probe tips and 100 ohm coaxial cables, each cable connecting one of said probe tips and one of the IC inputs. This structure introduces reverse signals into the channels that would seriously degrade probe operation if not removed. A capacitor and resistor in each probe tip, and in series with the coaxial cable and ground, match the impedance of the coaxial cable in the reverse direction, so that reverse signals are dissipated in the resistance and capacitance and do not reflect into the probe channels.

Abstract: A measuring apparatus is provided which is capable of measuring CN ratio. The measuring apparatus has a measuring band specifying unit for specifying a band under measurement; a display for displaying the spectrum of levels measured in the specified band; first and second noise measuring frequency specifying units; a transmission channel selector; and a CN ratio calculating unit for estimating a noise level at a carrier of a selected transmission channel and for calculating the CN ratio using the estimated level.

Abstract: A single sideband noise figure of a device under test is determined from double sideband measurements. A noise measurement system is provided, which includes a noise source, a mixer, a local oscillator, and a tunable intermediate frequency receiver. Three independent measurements are performed (one with the local oscillator frequency on the high side of the RF measurement frequency, another with the local oscillator frequency on the low side of the RF measurement frequency, and the third with the local oscillator frequency at the RF measurement frequency and the intermediate frequency at twice its former frequency). These noise power measurements are combined in such a way as to cancel the unwanted sidebands. Preferably, three output noise power measurements are also performed during a calibration so that the subsequent measurements are corrected for impedance mismatch errors.

Abstract: In this digital signal measurement apparatus, an approach is employed to deliver a measurement signal from a measurement signal generator to a measured circuit to transform the signal on the time base through the measured circuit to a signal on the frequency base by a frequency base transform circuit and to further obtain a signal on the time base by a time base transform circuit. Thus, a difference between the signal on the time base through the measured circuit and the signal on the time base from the time base transform circuit is employed. Thus, for example, even if the measured circuit is a linear system, a measured result in the digital region and a result of the analog measurement can be in correspondence with each other. Accordingly, gain correction of a measurement signal is unnecessary, thus making it possible to prevent an increase in an error of a measured result of S/N.

Abstract: An apparatus and a method for determining the error due to inherent PM and M noise in a noise measurement device. The apparatus is a calibration standard having a high frequency carrier source and a Gaussian noise source. The outputs of both sources are linearly combined by a power summer so that AM and PM noise components are equal at the output terminals of the calibration standard. To carry out the process of calibrating the calibration standard then determining inherent noise in a noise measuring device under test, the calibration standard includes means for switching to output a signal indicative of either the noise floor or a high frequency signal linearly combined with the output of a Gaussian noise source.

Abstract: A measuring circuit for the additive phase noise characteristic of a component in the vicinity of a carrier frequency. The measuring circuit is constructed of a central channel and two side channels. Each of these channels contains a model of the component to be characterized. Two phase detecting circuits are employed in which each processes an input signal from one of the side channels with an input signal from the central channel to generate signals which represent phase deviations between the two input signals. An intercorrelation circuit then utilizes the outputs from these phase detecting circuits to determine the characteristic additive phase noise of the component to be characterized by eliminating any additive phase noise superadded by other measuring circuit elements or induced by outside disturbances.