Abstract: Multiple views of the signal are generated by a time-sharing use of the oscilloscope's acquisition hardware. The instrument software makes a set of measurements of the input signal, and from the results of those measurements classifies the input signal as to type. Signals of particular types implicitly select suites of views of the signal. The operator sees examples of the other views available while a related view is the main view. Alternate views can be “live” miniature views, and displayed alongside in simplified form, alongside the main view. By clicking on them, these alternative views may be made to become the main view. The operator can add and modify views. Each view comes with a set of measurements that are automatically performed and the results are displayed on the screen as text annotation to the waveform. A different view of the signal comes with different automatic measurements, and presents the results of these measurements as annotations to the waveform image.

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: 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.

Abstract: A correction method for an electronic instrument accessory probe utilizes an error correction equation wherein at least one term contains an exponent less than unity. One simple such equation is: S=Cs2+Bs+A+b|s|x (where 0<x<1), but additional terms may be added, either with integer exponents greater than 2, or with other fractional exponents less than one. In the most simple embodiment, there are only four coefficients and the only term with a fractional exponent has an exponent of ½ (i.e., x=0.5). A second set of coefficients may be needed for the correction of negative values.

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: A circuit for detecting and automatically responding to ground faults. A passive protection PTC resistor is coupled in series with an active protection switch, the active protection switch being controlled by a control circuit to open the switch when excess current is detected to be flowing in the common path of one of the channels. Floating and grounded versions are described.

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: 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: 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: 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.

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.

Abstract: A method for rasterization of a set of voltage-versus-time data-address pairs into horizontal and vertical locations of a multi-bit raster display memory of a digital oscilloscope or similar electronic data acquisition instrument is disclosed. It provides a new way of controlling digital intensity, by allowing the operator and/or a function based on the instrument's trigger rate to set the number of intensity units available for brightening the pixels affected by the rasterization of each acquisition data pair. If a vector has more pixels than there are units of intensity available, the number of pixels that are to be brightened is limited but spread out over the vector's length by an algorithm that includes at least some degree of randomization. If there are more units of intensity available than there are pixels to put them in, the extra ones can either be distributed into each pixel or randomly added along the vector or ignored.

Abstract: A method by which a microprocessor based handheld multi-meter, or other handheld electronic instrument, can communicate with a computer or other microprocessor based device through the measurement input jacks of the handheld multi-meter. A handheld meter, thus equipped, can receive control or calibration data from, and provide test or calibration data to, a host computer or microprocessor based accessory or other instrument. To enable this capability, the handheld meter employs dual-signal, single-axis jacks, for example split banana jacks, for one or more of its signal and ground receptacles. The handheld meter and the computer, or another microprocessor based instrument or accessory device that the meter is to communicate with, are equipped with mutually compatible software and appropriate hardware to support single signal path communication.

Abstract: A very long linear input array capable of acquiring long series of acquisition data is achieved by breaking the long linear array into a series of sub-arrays, each enabled by a "global" set of enable signals. The individual cells of the local arrays are addressed by local x-y enable signals. This arrangement permits the acquisition of very long record lengths, without sacrificing the quality of other aspects of the acquisition process to excess capacitance.

Abstract: An adapter suitable for use with a handheld multimeter and a thermocouple probe contains a temperature sensor and input connectors suitable for mating with standard thermocouple probes. Both of these are closely coupled thermally to an isothermal domain. Plugs suitable for mating with the input jacks of a handheld multimeter are disposed within the adapter on the other side of a high thermal resistance zone. Conductors connect these outputs to the input connectors and to the leads of the temperature sensor. A four output version of the adapter is shown for use with a three lead temperature sensor, and a three output version is shown for use with a two lead temperature sensor. The output plugs can paired to be more compact and easier to use through the use of dual-signal single-axis banana plugs.

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: A method of analyzing and displaying waveforms by acquiring an electrical signal, converting it into a stream of digital data points, and sequentially storing each data point to a memory device. Then, analyzing each of the data points to detect whether the data point is an anomalous data point outside of a preselected range. Until an anomalous data point is detected, the steps of acquiring, converting, storing, and analyzing data are repeated. Shortly after the anomalous data point is detected, storage of the data points to the memory device is stopped, so that the anomalous data point and adjacent data points are preserved in memory. Then, the anomalous data point is displayed, preferably along with the immediately preceding and succeeding data points.

Abstract: A method and apparatus for measuring time intervals between electrical signals. A coincidence detection circuit is adapted to detect coincidence or near coincidence of two signals and to provide for selection from a plurality of predetermined delays to remove the coincidence. If the two input signals are periodic and have the same frequency, the apparatus also provides a signal from which both the time delay between the signals and the period of the signals may be determined at substantially the same point in time.

Abstract: A CMOS buffer amplifier can accept input signals and produce output signals that are within one half of the enhancement threshold voltage of the power supply voltages. These characteristics make this buffer amplifier ideal for use with low voltage CMOS circuitry with sub-micron geometries. The buffer amplifier contains two differential amplifiers, the output of both being combined and coupled to an output node. Each differential amplifier has matched input transducing devices on each of its inputs. One of these couples the input of the buffer amplifier to one of the inputs of the differential amplifier, while the other one couples the output of the buffer amplifier as feedback to the other side of the same differential amplifier. The pair of input transducing devices providing input to one differential amplifier are matched and suitable for operation in a higher voltage range than are the matched pair providing input to the other differential amplifier.

Abstract: A high-frequency calibration method and circuit including a dual path step attenuator. A calibration system is provided having a switch between the user signal input and the instrument input and an amplifier between the calibration signal input and the instrument input. The amplifier provides signal conditioning. The output of the amplifier is connected to the instrument input through a switch and a resistor, the resistor isolating the switch from the instrument input so as effectively to prevent degradation of the user input signal. A sense amplifier provides a calibration signal output indicative of the input impedance of the instrument input in response to a known stimulus. The input of the sense amplifier is isolated from the instrument input by a resistor. A current source provides a known stimulus to the instrument input to measure input impedance. A step attenuator is provided having an attenuated path and an unattenuated path.