Abstract: An apparatus and method for controlling and detecting the alignment of a color frame phase from a composite analog video signal decodes the composite analog video signal to produce a component digital video signal and to generate a color frame signal that represents the start of each color frame for the composite analog video signal. Based upon the color frame signal a flag signal is inserted into the component digital video signal. The component digital video signal is captured by an analyzer based upon the flag signal so that the captured component digital video signal is in color frame phase with a stored reference component digital video signal. Preferably the stored reference component digital video signal represents a test sequence having an integer number of color frames plus or minus one video frame.

Abstract: A PALC panel has narrow cathodes.

Abstract: A joint spatial-temporal alignment of video sequences uses a subsampled version of a reference video sequence for correlation with a corresponding subsampled version of a test video sequence in an iterative manner. The subsampled reference video sequence is obtained by detecting a temporal transition field in the reference video sequence, and then selecting a pair of fields from the reference video sequence that straddle the transition field separated by a given number of fields (time interval). Then starting from a current field of the test video sequence a pair of fields is selected separated by the same number of fields and correlated with the subsampled reference video sequence. If the correlation criteria are not satisfied, the current field in the test video sequence is incremented by one and the correlation process repeated until spatial-temporal alignment is achieved.

Abstract: A digital phase synthesizer includes a source of successive phase data signals. An interpolator generates successive edge placement data signals in response to each of the successive phase data signals. A phase modulator generates an output clock signal having edges placed at times determined by the successive edge placement data signals. Similarly, a digital phase analyzer includes a source of an serial binary input signal having edges. A phase demodulator generates successive data signals representing the location of each edge of the serial binary input signal. A decimator generates phase data signals at a lower rate than the edges of the serial binary input signal.

Abstract: A raster scan digital signal acquisition and waveform display instrument displays a dot representing a signal event with a color parameter in accordance with the value of a corresponding data word stored in a raster scan memory. A user interface control element supplies a single color parameter control value from which multiple independent control values for influencing the values of the data words stored in the raster scan memory in response to the single color parameter control value are generated.

Abstract: A system and method for in-service transmitter phase noise measurements determines phase nonlinearity by way of comparing unfiltered signal samples and regenerated reference signal samples to calculate phase nonlinearity error. Linear distortion is removed from the received signal samples in order to truly characterize nonlinear behavior of the transmitter. The unfiltered signal samples are generated without applying the receiver shaping filtering. Reference signal samples are regenerated from estimated transmitted symbols derived from the unfiltered signal samples. The transmitted symbols are estimated using a segmented slicer which dynamically estimates constellation decision levels from the unfiltered signal samples. A weighted, least-square based polynomial regression is performed on phase error samples of the unfiltered signal samples to estimate a phase nonlinear error function while suppressing the impact of other non-systematic distortions.

Abstract: A method and apparatus for transparently embedding data into a video signal modulates a particular carrier frequency with a randomized pattern representing the data. The randomized pattern may be a combination of the data with the output from a pseudo-random binary sequence generator, or the data may be converted first into a bi-orthogonal pattern selected from among a plurality of such patterns and then randomized. The resulting modulated carrier frequency is then amplitude modulated based upon a human visual model so that the modulated carrier frequency amplitude is greater in areas of high image complexity and lower in areas of low image complexity. The subliminal data represented by the modulated carrier frequency is added to the video signal.

Abstract: An in-service, realtime picture quality analysis method determines the degradation of a test video signal at a test point with respect to a reference video signal by generating from the reference video signal a set of parameters that characterize the images represented by the reference video signal. The set of parameters are inserted into a transport stream that also has an encoded version of the reference video signal. At the test point the set of parameters is extracted from the transport stream, and the test video signal is decoded from the transport stream. A corresponding set of parameters is generated for the test video signal, and the two sets of parameters are compared by a picture quality analysis algorithm to produce a picture quality rating that represents the degradation of the test video signal.

Abstract: A circuit for use in a DMM utilizes an auxiliary A/D converter to measure the battery voltage of the DMM and displays the result on the LCD display screen of the DMM. The user receives a numeric indication of the battery voltage measured, rather than a simple good/bad or bar graph indication. The voltage measured provides the user with a quantitative indication which allows the user to determine how close the battery is to being exhausted. Thus, the user can be made aware of a weakened state of the battery before operation of a backlight further drains the battery to an unacceptably low level.

Abstract: An apparatus and method useful in a test and measurement instrument for simultaneously adjusting both contrast and brightness via a single knob employs a family of modified gamma curves each having multiple breakpoints for mapping multiple-byte pixel intensity words into a multi-bit pixel intensity display control word. A single user-operable intensity control accomplishes selection of a particular gamma curve of the family of gamma curves, and causes the simultaneous adjustment of both contrast and brightness.

Abstract: An improved FIR filter based upon squaring is used to self-determine a filter constant equal to the sum-of-squares of the filter coefficients. An input signal is forced to zero for T samples, where T is the number of accumulator cells in an accumulator stage, and at the end of such zero samples the output from the filter is latched as the filter constant for use in filtering the normal input signal. The FIR filter may also be placed in a co-processor mode, using a FIFO register between the input of the FIR filter and a processor bus. A CPU on the bus initiates the co-processor mode and loads data into the FIFO. When the FIFO has data the data is read out and input to the FIR filter. The output of the FIR filter is placed on the processor bus. To determine the values of the filter coefficients loaded in the FIR filter, the data loaded by the CPU is an impulse signal having T−1 zero samples before and after an impulse sample, the output for each sample representing one of the filter coefficients.

Abstract: An electronic accessory assembly to be used with a host electronic instrument provides previously recorded data from a non-volatile memory as to the accessory's operational capabilities. This memory is accessed by a host device either when the host device is powered up, or when an new accessory is connected to the host device. The host device then uses this information along with the operational requirements of the user to set the operational parameters of the accessory/host combination to optimally perform the functions required by the user.

Abstract: A PIN diode switch reduces energy loss and stray capacitance by providing first and second series connected PIN diodes between first and second biasing sources. A third biasing source is coupled to the common node between the two PIN diodes via a first resistive element. A second resistive element is coupled between the PIN diodes and the second biasing source. An electronic switch couples a negative voltage source via a current generating means to bias the PIN diodes to a conductive ON state. AC current is coupled to ground in the ON state via a dual path circuit that includes one of the PIN diodes and a low loss capacitive element connected to the PIN diode and second resistive element node in one path and the other PIN diode and the biasing source to ground in the other path. In the OFF state the biasing sources provide reverse bias voltages for minimizing the reverse capacitance of the PIN diodes and are connected in a way that minimizes stray capacitance that is connected to the switched element.

Abstract: A method and apparatus for facilitating user interaction with a measurement instrument displays a control knob glyph corresponding to a user-adjustable parameter of the measurement instrument, the control knob glyph having an indicator and a partially circular drag area through which the indicator can be rotated. Inputs indicating amounts of rotational movement for the indicator can be received, and the location of the indicator within the drag area and the value of the parameter changed in response to such inputs.

Abstract: A new oscilloscope design improves the processing of acquired voltage-versus-time data through the efficient high speed acquisition and rasterization of such data into a form that includes multiple-bits-per-pixel intensity information. The multi-bit-per-pixel variable intensity rasterizer is optimized for maximum throughput and most efficient use of memory bandwidth. In the presence of faltering trigger rates, rasterization interruption provides a high probability of capturing the data associated with the slow triggers. Circuitry is provided to compensate for acquisition time and amplitude non-linearities. Many-bits-per-pixel intensity information is mapped into a fewer-bits-per-pixel format by a controllable transfer function that provides multiple viewing capabilities for the operator. Another mode of operation emphasizes infrequent events over commonly occurring ones using variations in brightness or color.

Abstract: An adaptive power supply for an avalanche photodiode (APD) is used to determine an optimum bias voltage. Without an optical signal input the adaptive power supply applies a swept voltage to the APD while monitoring the photodiode current. When breakdown occurs, the voltage is noted and the bias voltage from the adaptive power supply is set at a specified offset below the breakdown voltage. Where a source of optical digital data signal is present, it is coupled to the input of the APD via a programmable optical attenuator. The electrical digital signal output from the APD is input to a bit error rate counter, the output of which is monitored. For different optical power levels the APD bias voltage is swept by the adaptive power supply, determining a constant power level curve over which the bit error rate is virtually zero. This is repeated for a plurality of optical power levels, the resulting family of curves defining a region within the bit error rate is virtually zero.