Abstract: A method of quantifying perceptual information and entropy for a data input signal uses an appropriate perceptual model to produce a perceptual response. The perceptual response is then entropy converted to produce the perceptual information and entropy. The entropy conversion may include the application of a transform function, such as a Karhunen-Loeve transform function, to the perceptual response to produce a set of coefficients, which coefficients then have probabilities calculated for them based on coefficient histograms of massive tests. The probabilities are used to calculate the perceptual information and entropy using standard techniques. The perceptual information and entropy may be used in applications for achieving greater accuracy subjective quality determinations for the data input signal.

Abstract: A variable sample rate recursive digital filter is an adaptive digital filter where its coefficients are recalculated for each sample rate being processed in such a way as to maintain a constant frequency rate for all sample rates. An equivalent resampling is done by taking the ratio of the bilinear transforms at the respective sample rates. From an initial or calibrated sample rate and a corresponding initial filter coefficient, a new filter coefficient for a new sample rate is obtained by multiplying the initial filter coefficient by a constant or coefficient factor that is a function of the initial filter coefficient and a ratio of the initial and new sample rates: zFactor(z,R):=(1/z){(z(1+R)+(1?R))/(z(1?R)+(1+R))} The resulting new filter coefficient provides the adaptive digital filter with a constant frequency response when compared to the initial sample rate frequency response.

Abstract: An apparatus and method for predicting human vision perception and perceptual differences provides a perceptual difference model that merges two human vision systems, one for a reference video signal and the other for an impaired version of the reference video signal. The respective video signals are processed by spatio-temporal filters and, prior to differencing, by noise masking modules that apply a noise mask as a function of pupil size and luminance. The differenced filtered signal is an initial perceptual difference map to which other masking is applied to take into account correlation and contrast gain based upon the noise masks and filtered luminance from the spatio-temporal filters. The result is a more precise output perceptual difference map.

Abstract: An attachable/detachable variable spacing probing tip system has a housing that receives pivoting probing arms. Each probing arm has a support member and a probing arm portion of a flexible substrate having a conductive trace thereon. One end of each conductive trace is coupled to a probing contact and the other end coupled to an electrical contact pad on a electrical contact pad portion of the flexible substrate. Each of the probing arm portions has a generally S-shaped fold therein extending from the support members to the electrical contact portion of the flexible substrate. The housing includes means for pivoting the probing arms. The rear surface of the housing has a resilient member disposed therein. Latching means in the housing secures the electrical contact pad portion of the flexible substrate to the rear surface of the housing. Opposing attachment arms from a rear surface of the housing.

Abstract: An output termination auto detection circuit includes a reference resistance having one side coupled to a known input voltage and selectively coupled into a signal line of an input device. The other side of the reference resistance is coupled to an output terminal of the input device which is coupled to the input of a host instrument. The host instrument has an input resistance termination that functions as the output termination of the input device. A detection device is coupled to a common mode between the reference resistance and the input resistance of the host instrument for measuring the voltage at the node. Knowing the reference resistance, the input voltage and the output voltage at the node, the output termination of the input device (i.e. the input termination of the host instrument) can be determined and a indication of an improperly terminated input device may be provided to a user.

Abstract: A butt joined electronic assembly has first and second matching coplanar transmission structures that are independently aligned in a proximate abutting relationship. The coplanar transmission structures are formed on respective first and second electrical elements that are secured on respective independently positioned and mechanically joined first and second open end face carriers. The first and second matching coplanar transmission structures are electrically coupled together via substantially flat electrical conductors.

Abstract: A method of measuring frequencies of multiple sinusoidal bursts in a signal uses a time-domain window that includes all the bursts which are then transformed to the frequency by domain an FFT. The magnitudes of the frequency bins are filtered and smoothed to create a minimum magnitude threshold array. An adaptive threshold is calculated from the minimum magnitude threshold array, maximum magnitudes of the frequency bins and an adjustable constant. The magnitudes are then compared to the adaptive threshold and the number of consecutive frequency bins above the adaptive threshold are counted and, if correct for the given signal, a centroid is determined for each frequency bin. If the number of bursts is not correct, then the adjustable constant is altered and the adaptive threshold recalculated. The centroids are converted to measured frequencies for the multiple sinusoidal bursts.

Abstract: A fiber-pigtailed assembly for an optical detector with low back reflection and minimal polarization-dependent responsivity has a detector surface mounted adjacent a beveled end of a fiber pigtail such that the detector surface is tilted and rotated with respect to the beveled end of the fiber pigtail. Also an external optical fiber may be coupled to the fiber pigtail with low back reflection and minimal polarization-dependent responsivity by having an input ferrule at the end of the external optical fiber, the end being beveled; by having an intermediate ferrule at a coupling end of the fiber pigtail, the coupling end being beveled while the other end of the ferrule is beveled by the same amount but approximately orthogonal to the coupling end; and by having an output ferrule on the fiber pigtail adjacent to the intermediate ferrule, the end of the output ferrule adjacent to the intermediate ferrule being beveled.

Abstract: A dither system for a quantizing device, such as a multi-stage pipelined analog-to-digital converter (ADC), derives a dither signal from a clock signal having a sample frequency, the dither signal having a frequency that is one-third of the sample frequency. The dither signal is easily converted to analog and added at the input of the quantizing device to an analog signal to be digitized. A cancellation signal circuit generates a cosine-wave signal from a digital version of the dither signal and programmable coefficients that are a function of amplitude and phase. The cosine-wave signal is combined with the digital output signal from the quantizing device to produce a corrected digital output signal having reduced quantization distortion.

Abstract: An oscilloscope that is capable of displaying simultaneously multiple waveforms representing time evolution of a signal during respective acquisition intervals acquires waveform data using a first set of acquisition parameters and generates a display based on that waveform data. If the display includes a waveform that is visually distinct from other displayed waveforms, the user selects a feature that distinguishes the visually distinct waveform from other displayed waveforms. The oscilloscope automatically derives updated acquisition parameters that discriminate between the selected feature and other features of the displayed waveforms. The oscilloscope then acquires waveform data using the updated acquisition parameters and generates a display based on that waveform data.

Abstract: A signal acquisition instrument, such as an oscilloscope, having an input stage that is referenced to a user's ground is disclosed. Information gathered by the input stage is stored in a storage element powered by a floating power supply that is referenced to the user's ground. After storage, the storage element is disconnected from the floating power and from the user's ground and switched to a power supply referenced to the remainder of the system. FET switching is beneficial, and information can be stored either in an analog format or in a digital format.

Abstract: Locating of points of interest in an impaired image derived from video processing of a reference image is achieved by generating an impairment map for the impaired image. Then a cross-fade is performed between the impaired image and the impairment map so that points of interest indicated by the impairment map are accurately located on the impaired image.

Abstract: Temporal processing for realtime human vision system behavioral modeling is added at the input of a spatial realtime human vision system behavioral modeling algorithm. The temporal processing includes a linear and a non-linear temporal filter in series in each of a reference channel and a test channel, the input to the reference channel being a reference image signal and the input to the test channel being a test image signal that is an impaired version of the reference image signal. The non-linear temporal filter emulates a process with neural attack and decay to compensate for a shift in peak sensitivity and for frequency doubling in a spatio-temporal sensitivity function. The linear temporal filter accounts for the remaining subtleties in the spatio-temporal sensitivity function.

Abstract: A data transformation algorithm is selectively applied to each data vector as it enters the pipelined structure. In a selection step, the algorithm compares the bit value of the new data vector with the corresponding bit values of the preceding data vector, and sums the number of logic transitions. The transformation algorithm is applied to the new data vector only if it would reduce the resulting number of transitions, otherwise the data vector is propagated unmodified. Bit inversion is a data transformation algorithm according to the present invention that provides up to a 50% reduction in the number of logic transitions.

Abstract: A system, method, and apparatus for maintaining the status of communications between a wireless client and a content source is presented herein. During periods where the wireless link at the wireless client has deteriorated, a wireless content switch prevents timers at the content source from expiring by transmitting an acknowledgment message to the content source. The acknowledgement also stops the content source from transmitting data packets to the wireless client by indicating a zero window size. Additionally, during the time period that the wireless link to the wireless client is deteriorated, the wireless content switch responds to communications from the content source for the wireless client.

Abstract: An improved self-adjusting I-Q modulator system has a quadrature modulated carrier output that is input to a waveform acquisition circuit for obtaining a full waveform from which both amplitude and phase measurements are obtained. Calibration occurs by setting respective I and Q inputs to the multipliers to zero and adjusting corresponding variable offset voltages to null the modulated carrier output. Then a voltage reference is selected by each I and Q input path in turn, and the amplitude and phase of the modulated carrier output for each I and Q channel are measured. Respective phase shifters for a carrier signal are adjusted to move the outputs of the phase shifters toward a quadrature relationship in response to the measured amplitude and phase of the full waveform. These steps are repeated until the phases of the I and Q channels are in quadrature.

Abstract: Methods for displaying an anomaly in a periodic waveform. Specifically, in one embodiment according to the present invention, a method is provided of (a) setting a pulse start address, (b) setting an initial screen position, (c) displaying a pulse at a time-aligned position, (d) updating the pulse start address in response to a pulse width value, (e) repeating (c) and (d), and (f) interactively adjusting the pulse width value at any time without using a clock recovery procedure.

Abstract: A method of remotely estimating the functionality of a preamplifier mounted adjacent an antenna at the top of a mast or tower and coupled to a base station via a transmission medium, such as a coaxial cable, includes taking noise and/or signal power measurements at the base station via the coaxial cable for the amplifier when both powered and unpowered. The ratio of the respective noise and/or signal powers, after the receiver noise figure at the base station and the cable loss (estimated or measured) including any connection device loss are accounted for, provides an estimate of the functionality of the amplifier.

Abstract: An instrument has a single video input port for receiving either analog or serial digital video signals coupled to both an analog and a serial digital video input path. The outputs of the analog and serial digital video input paths are provided as respective inputs to a video switch, the output of which is then provided to the instrument for further processing. Information from the serial digital video input path, which may include clock recovery lock, carrier detect and/or video standard, is provided to a decision module that generates a select signal for the video switch. As an example, if “lock” is present, then the output from the serial digital video input path is selected automatically for output by the video switch, otherwise the output from the analog video input path is selected automatically. The automatic selection for the switch may be manually overridden.