Abstract: A rear-mount integrated rotary encoder comprises a mechanical portion and a printed circuit board portion. The mechanical portion of a rear mount integrated rotary encoder comprises a housing including a bushing for receiving one end of a rotatable. The rotatable shaft passes through an open front portion of the housing and is mechanically connected to exposed rotatable circuit contacting members. The printed circuit board portion has an encoder contact pattern formed thereon. The printed circuit board has an area larger than the cross sectional area of the housing. The encoder contact pattern surrounds an aperture in the circuit board. The rotatable shaft of the rotary encoder is passed through the aperture such that the rotatable circuit contacting members contact the encoder contact pattern on the circuit board. The housing includes projections, substantially orthogonal to the circuit board, for engaging a feature of the circuit board for securing the integrated encoder in an assembled state.

Abstract: A system for determining the phase and magnitude of an incident signal relative to a cyclical reference signal, includes a sampler for sampling the incident signal. Autoranging circuitry is responsive to the reference signal and determines the frequency f of the reference signal and sets the sampling rate sr of the sampler. A processor, responsive to the sampler, computes a single point DFT v of the sampled incident signal responsive to the frequency of the reference signal and determines the phase &thgr; and magnitude |v| of the incident signal relative to the reference signal in response to the single point DFT.

Abstract: A method of operating an oscilloscope includes acquiring waveform data using a group of default acquisition parameters, analyzing the acquired waveform data in accordance with a selected one of several rule sets and deriving an optimized group of acquisition parameters. The method then proceeds by acquiring waveform data using the optimized group of acquisition parameters, and displaying the waveform data acquired using the optimized group of acquisition parameters.

Abstract: A portable general-purpose oscilloscope employs circuitry for receiving and converting serial digital video signals to composite and component analog signals via a digital to analog converter. The converted analog signals are applied to signal inputs of the oscilloscope for monitoring and display. Preferably, the oscilloscope is a digital phosphor oscilloscope. The oscilloscope control menus are arranged to control all of the usual functions of the oscilloscope and also to control the serial digital video circuitry. Apparatus is provided for storing data and waveforms. Circuitry is disclosed for deriving a trigger signal from a specific digital word of the serial digital bit stream. The trigger signal is applied to the trigger input terminal of the oscilloscope to allow the oscilloscope capture and display television waveform information around a unique occurrence of an event, as specified by the digital word.

Abstract: Arbitrary sets of samples may be suppressed from display and analysis. The resulting record may then be saved in its abbreviated form or discarded. Such a record may also be retrieved and arbitrarily partially suppressed a second or third time, making a series of smaller and less complete acquisition histories. Each of these records may be saved with or without suppressed samples and may be later redisplayed reliably showing those samples originally saved.

Abstract: A method for calibrating an instrument includes maintaining typical response values at respective frequency locations. The response of the instrument being calibrated is measured at a subset of frequency locations in the typical response. Response values for frequency locations not in the subset are estimated from the typical and measured response values. The instrument is calibrated based on the actual and estimated response values. Apparatus for calibrating an instrument includes a signal generator, coupled to the instrument, which generates a signal having known characteristics. A controller, coupled to the instrument, generates a calibration signal. Controller memory stores typical response values at respective frequency locations, and measures response values at a subset of the frequency locations. Response values for frequency locations not in the subset are estimated from the typical and measured response values. The instrument is calibrated in response to the measured and estimated response values.

Abstract: A digital storage oscilloscope includes a source of two or more input signals and a display device. An alternate triggering mechanism includes a selector for selecting one of the input signals. A trigger circuit is responsive to the selected input signal, and generates a trigger signal when a trigger condition is satisfied. A raster signal generator includes a plurality of waveform memories each associated with a respective input signal and responsive to the trigger signal for storing data representing the selected input signal in the waveform memory associated with the selected input signal. The raster signal generator generates a raster image signal representing the selected input signal.

Abstract: In a logic analyzer or similar binary signal-analyzing instrument, hardware circuitry, such as an ASIC, or other dedicated hardware, is used to perform waveform compression and summarization more rapidly than it could be done by software alone. The hardware is used to perform the compression of the data and to summarize its behavior for visual display. In one embodiment, the hardware starts from a given memory address and compares current timestamp values with final timestamp values to determine the length of the timeslice. Within the timeslice, all of the data is compared to determine whether it remains the same throughout the timeslice or whether it changes. The same approach can be used on violation data, such as glitches and setup and hold violations.

Abstract: A circuit for acquiring a differential signal and a single-ended signal from a differential signal bus generates a differential output strobe signal and a single-ended strobe signal. A differential amplifier, first and second single-ended amplifiers, and a logic circuit cooperate to produce a digital logic output signal that exhibits an active edge that always occurs later in time than an active edge of the differential output strobe signal.

Abstract: A method and apparatus for probing a terminal of a ball grid array device, or a conductor of an array of closely-spaced conductors, preferably employs a buried tip resistor located substantially adjacent to the point to be monitored. In this way, a relatively short stub is provided from the connection point to the tip resistor. A receiver amplifier arrangement substantially eliminates an offset error affecting prior art amplifier arrangements, where the offset error is introduced into the signal to be measured due to variation in the resistance value of the tip resistor. It is recognized that the invention is not limited to buried-resistor applications, but is also applicable in probing situations involving the use of tip resistors having a tolerance range greater than 1%.

Abstract: A digital storage oscilloscope includes first and second memory modules each including a data input section for receiving an input stream of digital data words and generating a sequence of address words, an acquisition memory which is addressed utilizing the address words for storing the data words, and a trigger input section for receiving a discrete input trigger and supplying the discrete input trigger to the data input section for initiating termination of an acquisition. The data input section of the first memory module passes the stream of digital data words to the data input section of the second memory module and supplies a discrete trigger to the trigger input section of the second memory module.

Abstract: An apparatus and method for determining the period of a data signal encoded using PN sequences may be implemented using software, and takes advantage of the fact that the signal is generated based upon a pseudo-random binary sequence, and of the fact that the order of the characteristic polynomial is known. The apparatus and method uses knowledge about the structure of the signal generator (i.e. the order of the characterizing polynomial of the encoding PN sequence), and recognizes the fact that short data tokens from the original signal can be used with the same success in determining the period as longer sequences having at least the length of the period.

Abstract: The subject invention addresses the problem of aliasing in subsampled data by adding dither to the timing of the subsampling of the data. The subject invention solves a speed problem caused by delays in modifying (i.e., dithering) the A/D converter sampling clock. It is herein recognized that to maintain a high acquisition rate one should randomly select (i.e., dither) samples after demultiplexing the data into a wider and slower stream of samples, rather than attempting to modify the high speed A/D converter sampling clock.

Abstract: A probe or accessory incorporating the features of the subject invention includes a communications arrangement for communicating topology-related data to a host instrument connected to the probe or accessory. The topology-related data describes the probe or accessory as a network comprising multiple paths from the probe tip to host instrument input connector. Each path is associated with a feature of the probe or accessory, and only one path may be active at any given time. Each feature is described by a unique number, called a “tag”. New tags may be assigned when necessary so long as existing tags are not disturbed. A probe or accessory in accordance with the subject invention transmits a list of “Required Tags” to the host instrument. Each required tag is associated with a pathway within the probe or accessory. The host instrument may only exercise those paths for which all required tags are understood, or those for which no required tag is designated.

Abstract: A system for displaying waveforms representing an input signal includes a display subsystem, coupled to a source of the input signal, for displaying a waveform representing the input signal in response to a display control signal. A trigger circuit is coupled to the input signal source and detects a trigger event. A time displacement circuit is coupled to the trigger circuit and generates a time displaced trigger signal a controllable amount of time after detection of the trigger event. A switch is coupled between the trigger circuit, the time displacement circuit, and the display subsystem. The switch selectively generates a display control signal in response to either the detected trigger event or a time displaced trigger signal.

Abstract: An apparatus and method for performing an auto-ranging function in electronics test equipment monitors both the RMS value and the peak value of the input signal to be measured. In the subject system, a peak signal measurement which exceeds the dynamic range of the currently-selected range will cause selection of the next higher range. A peak signal measurement which would exceed the dynamic range of the next lower measurement range, will prevent selection of the next lower range when the RMS value would otherwise have caused that selection. A peak signal value which does not exceed the dynamic range of the currently-selected measurement range, or the dynamic range of the next lower measurement range will allow control of measurement range selection to be determined by the RMS value of the input signal.

Abstract: The present invention relates to a method for checking a data exchange between participants in a call established on a communication medium in compliance with a protocol. In order to identify the various stages in a call process conforming to the protocol and to break said protocol once the checking procedure has started, the invention suggests that the data exchange be captured by-means of a protocol monitor (PM) connected to a communication medium (CM) and based on the finite state automaton principle. The test automaton contains the same states and state variables as the protocol automaton designed to define the communication protocol, apart from the fact that the test automaton is allocated a plurality of values within the same range of corresponding state variable values in the protocol automaton.

Abstract: A cooling system for a test and measurement instrument including a variable-speed fan, useful with different instruments having different configurations, employs a plurality of sensors disposed at predetermined locations within an enclosure of the instrument, and is software programmable with predetermined parameters of each particular configuration of each particular instrument. At least one of the sensors measures the temperature of a component that dissipates power at a substantially constant rate, and at least one of the sensors does not include a heat source to provide heat for measurement.

Abstract: An ultra high frequency current probe is fabricated in the form of a surface mount device, designed to be a part of the circuit providing the current being observed.

Abstract: Unusual waveforms are defined in terms of how many “new” pixels are affected by the process of rasterizing them. New pixels can be those not yet affected by the rasterization of any waveform in the current set of acquisitions, or to be those that have had higher values in their raster memory location but have now been decayed to below a defined value. Once detected, such waveforms can be re-rasterized with extra intensity or into a different color by using a reserved range of values of those storable in the raster memory. Alternatively, the special region of values can be used as a counter/timer to maintain the pixels associated with unusual waveforms at a brightest intensity value, or in the color equivalent, for an extended period of time. User input can be used to affect the definition of “new” pixels and to control the special persistence given to unusual waveforms. Unusual waveforms can also be saved in long term memory.