Abstract: Described are systems and methods of estimating a Signal-to-Noise (S/N) ratio of an input channel carrying a QAM signal. A Modulation Error Ratio (MER) is calculated for the input QAM signal, but uses only the centermost error values of a constellation of the input QAM signal in generating this modified MER. The modified MER accurately represents the S/N ratio of the input channel carrying the QAM signal. In this way the S/N ratio may be accurately determined using only the received I and Q components of the modulated QAM input signal itself.

Abstract: Tiling or blockiness detection based on spectral power signature uses one-dimensional vectors at block edges to find a spectral signature created by the tiling or blockiness in an image. A baseband component of the image, such as luminance, is edge enhanced, and then the pixel values along each horizontal line are summed to form a one-dimensional column vector of summed edge values for the image. The power of the column vector and the power of selected frequency components within the column vector are determined. The powers are then combined and converted to dimensionless tiling or blockiness values relative to each of the selected frequencies.

Abstract: A stereoscopic video temporal frame offset measurement system uses an improved signature curve generator to generate a robust signature curve for each of the left and right image sequences of a stereo video signal. The resulting signature curves are cross-correlated over a specified correlation range to generate cross-correlation coefficients. The cross-correlation coefficients are compared to a high threshold, and a temporal frame offset is generated and displayed for each cross-correlation coefficient that exceeds the high threshold. Each new temporal frame offset result is highlighted when displayed, otherwise the last result is displayed in a background fashion.

Abstract: Embodiments of the present invention provide systems and methods for non-invasive, “in-service” AV delay detection and correction. These systems and methods do not modify the audio signal or the video signal, nor do they rely on any metadata to be carried with the audio signal or the video signal via the distribution path. Instead, agents located at various points along the distribution path generate very small signature curves for the audio signal and the video signal and distribute them to a manager via a separate data path other than the distribution path. The manager calculates a measured AV delay caused by the distribution path based on these signature curves, and then optionally corrects the measured AV delay by adjusting an in-line delay in the distribution path.

Abstract: A flexible timebase for eye diagrams uses a stable free running oscillator as a sample clock for equivalent time sampling of an input serial digital signal and of a reference signal, derived from a subdivided recovered clock of the input serial digital signal. The reference signal samples are provided to a digital phase-locked loop that provides the flexible timebase to an eye pattern generator. The eye pattern generator accumulates the input serial digital signal samples at times corresponding to the reference signal samples to produce the eye diagram. A linear phase detector in the digital phase locked loop converts the reference signal samples to a complex signal using a Hilbert transform and then to a linear ramp of phase values using a CORDIC algorithm with arctangent lookup table. A subtractor then subtracts the digital phase-locked loop feedback from the linear ramp to provide the input to the loop filter.

Abstract: Embodiments of the present invention provide a “disparity cursor” for easily measuring disparity within a selected region of a 3D image under test. In operation, a user places a window that defines the disparity cursor over a selected region of the 3D image under test using a mouse, keyboard, or other user-interface device. An average disparity value for the image segments contained within the window is then automatically calculated and reported to the user.

Abstract: A method of generating a stereoscopic image registration and color balance evaluation display enables a user to align two cameras used to produce a stereoscopic video signal or to analyze a received stereoscopic video signal. Left and right images from the cameras are converted into desired video signal components. Corresponding pixels from the left and right images are compared for each of the video signal components, and plotted as x and y inputs to a Cartesian plot to produce respective two-dimensional (2D) histograms. The multiple 2D histograms are presented as a Quad Diamond display so a user may align the two cameras or analyze the received stereoscopic video signal.

Abstract: A single-ended blur detection probe and method with a local sharpness map for analyzing a video image sequence uses two sets of edge filters, one for “fast edges” and the other for “slow edges.” Each set of edge filters includes a horizontal bandpass filter, a vertical bandpass filter and a pair of orthogonal diagonal filters where the frequency response of the fast edge filters overlap the frequency response of the slow edge filters. The video image sequence is input to each filter of each set, and the output absolute values are combined with weighting factors to produce a slow edge weighted sum array and a fast edge weighted sum arra. The respective weighted sum arrays are then decimated to produce a slow edge decimated array and a fast edge decimated array.

Abstract: A test pattern for evaluating L/R crosstalk extinction ratio in a stereoscopic 3D system has a strip of one characteristic—polarization, white, color—associated with a plurality of calibrated chips in a left eye image and a strip of a contrasting characteristic—orthogonal polarization, white, contrasting color—associated with a plurality of calibrated chips in a right eye image such that, when the two images are superimposed, the strip of one image overlays the calibrated chips of the other image. By alternately occluding one eye while observing the superimposed image with the other eye, a portion of the strip of the occluded eye image appears across the chips of the viewing eye image when there is crosstalk. The extinction ratio value associated with the chip of the viewing eye image that most closely matches the portion of the strip from the occluded eye image is an estimate of the L/R crosstalk.

Abstract: A flexible timebase for eye diagrams uses a stable free running oscillator as a sample clock for equivalent time sampling of an input serial digital signal and of a reference signal derived from a subdivided recovered clock of the input serial digital signal. The reference signal samples are provided to a digital phase-locked loop that provides the flexible timebase to an eye pattern generator. The eye pattern generator accumulates the input serial digital signal samples at times corresponding to the reference signal samples to produce the eye diagram. A linear phase detector in the digital phase locked loop converts the reference signal samples to a complex signal using a Hilbert transform and then to a linear ramp of phase values using a CORDIC algorithm with arctangent lookup table. The digital phase-locked loop feedback is subtracted from the linear ramp to provide the input to the loop filter.

Abstract: A flexible timebase for eye diagrams uses a stable free running oscillator as a sample clock for equivalent time sampling of an input serial digital signal and of a reference signal, such as a sine wave, derived from a subdivided recovered clock of the input serial digital signal. The reference signal samples are provided to a digital phase-locked loop that provides the flexible timebase to an eye pattern generator. The eye pattern generator accumulates the input serial digital signal samples at times corresponding to the reference signal samples to produce the eye diagram. A linear phase detector in the digital phase locked loop converts the reference signal samples to a complex signal using a Hilbert transform and then to a linear ramp of phase values using a CORDIC algorithm with arctangent lookup table. A subtractor is then used to subtract the digital phase-locked loop feedback from the linear ramp to provide the input to the loop filter.

Abstract: Embodiments of the present invention provide systems and methods for non-invasive, “in-service” AV delay detection and correction. These systems and methods do not modify the audio signal or the video signal, nor do they rely on any metadata to be carried with the audio signal or the video signal via the distribution path. Instead, agents located at various points along the distribution path generate very small signature curves for the audio signal and the video signal and distribute them to a manager via a separate data path other than the distribution path. The manager calculates a measured AV delay caused by the distribution path based on these signature curves, and then optionally corrects the measured AV delay by adjusting an in-line delay in the distribution path.

Abstract: Aspects of the present invention are related, in general, to Type-III phase-locked loops. In particular, aspects of the present invention relate to analog Type-III phase-locked loop arrangements comprising at least two signal paths, wherein each signal path may correspond to a bandwidth partition and may be selected by a selector according to a bandwidth parameter value. According to one aspect of the present invention, a first signal path may correspond to a fast loop (wide closed-loop bandwidth), and a second signal path may correspond to a slow loop (narrow closed-loop bandwidth).

Abstract: A wander gamut display for perturbation analysis is created by determining from a periodic input data signal and a reference clock a frequency offset and frequency drift rate for the input signal. The frequency offset and frequency drift rate are input to respective orthogonal axes of a Cartesian display together with a wander limit bounding box that defines the wander gamut. Values that fall outside the bounding box on the display indicate wander that may result in data errors.

Abstract: Aspects of the present invention are related, in general, to Type-III phase-locked loops. In particular, aspects of the present invention relate to analog Type-III phase-locked loop anangements comprising at least two signal paths, wherein each signal path may correspond to a bandwidth partition and may be selected by a selector according to a bandwidth parameter value. According to one aspect of the present invention, a first signal path may correspond to a fast loop (wide closed-loop bandwidth), and a second signal path may correspond to a slow loop (narrow closed-loop bandwidth).

Abstract: A system and method are provided to generate a histogram of jitter peak values within histogram hardware. The histogram is then transferred to a jitter analyzer, which is implemented in either dedicated hardware or software running on a general purpose processor. The jitter analyzer calculates a cumulative distribution function (CDF) array and a complementary cumulative distribution function (CCDF) array based upon the histogram, and determines the peak jitter values based upon a probability value.

Abstract: A method of two-way authentication between a user and a known host using a non-disclosing password entry system generates a matrix of characters having a random characteristic with random characteristics being selected from a set of custom symbols, pictures or patterns (rather than alpha-numeric characters) that only the user recognizes. When the user sets up an account with the known host, a subset of these characteristics is predetermined for use specifically by the user. One or more of these may additionally be used in the user's PIN or password for easy memorization, allowing the user to first authenticate the log-in screen before the user enters the PIN for user authentication to the known host. Alternatively, randomized alpha-numeric characters may be used, but with a predefined grouping or subset of the characters in a predefined position on the initial character matrix presentation.

Abstract: A non-disclosing password entry method is achieved by displaying an ordered arrangement or matrix of characters such that an authorized user's password is predetermined from a subset of these characters. The characters in the display are associated with a randomly ordered set of patterns or colors as, for example, the character background in the display. Additionally there is provided a means for selecting each type of pattern or color. Rather than entering the password directly, the authorized user is authenticated by noting the background pattern or color associated with the first character of the password and then selecting that pattern or color. The process is repeated with each password character in sequence until all the characters have been selected. The authorized user is authenticated by verifying that the selected backgrounds are correct for each of the characters of the password.

Abstract: An artistic color gamut display is generated by obtaining maximum and minimum values for an RGB signal. The maximum and minimum values are used as X and Y values for an XY plot. A triangular graticule, or Spearhead display, is generated for the XY plot having a first side representing Lightness, a second side representing saturation and a third side representing Value. The area within the Spearhead display represents valid color gamut. The Spearhead display may be combined with more traditional displays, such as Vector or Arrowhead displays, to provide a completely three-dimensional analysis of the RGB signal in terms of the artistic parameters of Hue, Saturation and Value or Lightness.

Abstract: An automated lip sync error corrector embeds a unique video source identifier ID into the video signal from each of a plurality of video sources. The unique video source ID may be in the form of vertical interval time code user bits or in the form of a watermark in an active video portion of the video signal. When one of the video signals is selected, the embedded unique video source ID is extracted. The extracted source ID is used to access a corresponding delay value for an adjustable audio delay device to re-time a common audio signal to the selected video signal. A look-up table may be used to correlate the unique video source ID with the corresponding delay value.