Abstract: A test and measurement Instrument samples an input digital logic signal to produce logic samples, compresses the logic samples into compression codes, and stores the compression codes into acquisition memory. Compression includes parsing the logic samples into groups and assigning compression codes to those groups, and is performed so as not to lose information about the input digital logic signal's activity. The instrument converts the stored compression codes into a waveform image in display memory and displays the stored waveform image on a display device.

Abstract: An improved digital trigger circuit has a plurality of data samples extracted from an input electrical signal for each sample clock cycle. The plurality of data samples are compared in parallel with a high threshold level and a low threshold level which provides hysteresis for noise rejection. Also the plurality of data samples are used to determine sub-sample trigger positioning. The comparison outputs are input to a digital trigger logic circuit for identifying a selected trigger event and generating a trigger for the acquisition of data from the input electrical signal for analysis and display. The digital trigger logic provides edge event triggering, pulse width triggering and transition time triggering, among others.

Abstract: A multiple probe acquisition system, such as for use with a value instrument, uses probes where each probe includes an acquisition circuit for acquiring from a circuit under test an electrical signal as digital data at a high rate, and then transferring the digital data from the probe to the instrument at a lower rate over a data bus for processing and display. The probe may be used to acquire analog waveforms or logic data from the electrical signal. The probe provides a very low input capacitance to the circuit under test, minimizing signal distortion, and is relatively inexpensive. The probes are time aligned by detecting when one of the probes generates a trigger, and timing the other probes to stop acquisition simultaneously so the data is synchronized among the probes.

Abstract: A self-hold motor protector (10) has an open metallic housing (12) in which a thermostatic disc (14) carrying a movable electrical contact (18) is cantilever mounted. A heater seat plate (20) is mounted in the housing in electrical and thermal relationship therewith. The heater seat plate has a seating recess (20a) in which a positive temperature coefficient resistor heating element (22) is received with one contact surface in electrical and thermal engagement with the heater seat plate. A terminal plate (26) mounts a stationary electrical contact (28) and is received over the opening of the housing but electrically isolated therefrom by a gasket (24). An electrically conductive spring (30) extends between the terminal plate and a second contact surface of the heating element.

Abstract: A DDS pulse generator has an accumulator that accumulates a phase increment value to produce phase accumulator values, and has a lookup table that contains a digital representation of a pulse waveform such that a pulse output signal is produced from the lookup table in response to the phase accumulator values. To change a period of the pulse output signal without changing edge positions a programmable modulo value is used. An address mapper is situated between the accumulator and address lines of the lookup table to map the rising and falling edge portions of the phase accumulator values into large regions of the lookup table, while phase accumulator values corresponding to high and low logic levels are mapped into small regions of the lookup table. The resulting pulse output signal has easily independently controlled period and pulse width as well as rising and falling edge speeds.

Abstract: A triggered DDS generator architecture accumulates a phase increment value in response to a DDS clock to generate phase accumulator values for addressing a waveform lookup table which contains a desired output signal. A time measurement circuit determines a time interval between the arrival of a trigger signal and a subsequent cycle of the DDS clock, which time interval is used to either adjust an initial phase accumulator value or delay the DDS clock so that a constant time is maintained between the arrival of the trigger signal and the desired output signal.

Abstract: A method and apparatus for an improved timer circuit and improved pulse width detection includes initiating a ramp timer and setting a timer latch output level substantially simultaneously in response to the occurrence of an input signal. The occurrence of the input signal also causes a counter to be enabled to count clock cycles. The ramp timer signal of the ramp timer is frozen (i.e., paused) by a timer control circuit, upon the occurrence of a first clock cycle following the enabling of the counter. The counter then counts a predetermined number of clock cycles after the ramp timer signal is frozen and, upon the occurrence of a last one of a predetermined number of clock cycles, generates a terminal count signal. Upon receiving the terminal count signal, the timer control circuit unfreezes ramp timer signal. The ramp timer runs until completion at which time the ramp timer generates an end of ramp control signal. The control signal is communicated to timer latch to reset timer latch output level.

Abstract: A solid state motor protector has a first PTC chip (positive temperature coefficient of resistivity) electrically connected in series relation with a second resistor having a generally fixed temperature coefficient of resistivity and mechanically coupled to the first resistor in close/direct thermal coupling. Another embodiment has a plate like isolator (52) formed with an opening receiving a polymer PTC chip (58) and having terminals (54, 56) which serve as fixed resistors. Yet another embodiment has an additional PTC resistor and a fixed resistor used in a motor reversing mechanism. Still another embodiment has a fixed resistor on either side of a PTC resistor for use in protecting the windings of a single phase motor. Another embodiment has a stack of polymer PTC resistor chips (82a–82d) with one chip serving as a voltage blocking chip and the other chip serving as fixed resistors.

Abstract: A current interrupter (10, 10′) includes bimetallic member (18) as a switching member having a formed portion (18a) providing snap action movement between oppositely dished configurations. An integrally formed extended length portion (18b) having a stiffening feature extends from the formed portion and mounts a movable contact at its free end. Stiffening feature embodiments include folded opposed marginal edges and one or more longitudinally extending ribs formed in the extended length portion. In one embodiment, the bimetallic member is cantilever mounted in a housing member (14). In another embodiment, a bimetallic member (18D) has first and second extended length portions (18b) extending from opposite sides of a formed portion to provide a circuit interrupter with a double break system.

Abstract: A solid state motor protector has a first PTC chip (positive temperature coefficient of resistivity) electrically connected in series relation with a second resistor having a generally fixed temperature coefficient of resistivity and mechanically coupled to the first resistor in close thermal coupling. In a first embodiment, a polymer PTC resistor (12) and fixed resistor (14) are stacked together along with a spring member (22) and received in an open ended isolator (16) with terminal plates disposed respectively on the top and bottom of the isolator to load the spring and electrically connect the stack. A second embodiment has the sidewall of a cup-shaped terminal (32a) insert molded in the isolator (32) with another cup-shaped terminal received on and clamped to the isolator. A third embodiment has a plate like isolator (52) formed with an opening receiving a polymer PTC chip (58) and having terminals (54, 56) which serve as fixed resistors.

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: A current interrupter (10, 10′) includes bimetallic member (18) as a switching member having a formed portion (18a) providing snap action movement between oppositely dished configurations. An integrally formed extended length portion (18b) having a stiffening feature extends from the formed portion and mounts a movable contact at its free end. Stiffening feature embodiments include folded opposed marginal edges and one or more longitudinally extending ribs formed in the extended length portion. In one embodiment, the bimetallic member is cantilever mounted in a housing member (14). In another embodiment, a bimetallic member (18D) has first and second extended length portions (18b) extending from opposite sides of a formed portion to provide a circuit interrupter with a double break system.

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: End cap apparatus (2) is received in the open end of an electrochemical cell casing (6) and is particularly adapted to be crimped thereto electrically separated from the casing by a gasket (4). The end cap apparatus incorporates current interrupt safety protection features including high rate overcharge protection through an over-temperature and/or low pressure switch (22, 12d-18, 18′, 18″, 118a), low rate overcharge and overdischarge protection through a low pressure switch (12d-18, 18′, 18″, 118a), extended short circuit protection through an over-temperature switch driven by l2r heating of internal components (20, 22, 16, 12, 12′, 16′, 16″, 16′″, 12v, 102, 122, 120), and pressure venting through a frangible portion (12e) of a diaphragm. The diaphragm can be integrally formed with a header (12, 12″, 12′″, 12iv) or can be a separate element (32, 82, 92, 108, 112, 112′ 112″, 112′″).

Abstract: A pressure actuated current interrupt device particularly useful for prismatic electrochemical cells has a cup-shaped member (12, 12′, 12″, 12′″, 12IV, 12V, 12VI) mounted on the cover of the cell and arranged to protrude into the interior of the cell. The cup-shaped member can be formed either as a separate member or as a portion of a layer of a composite cover. The cup-shaped member has a side wall (12b) in which stress is created by pressure generated in the cell which acts on the generally flat end wall (12a) of the cup-shaped member. A selected amount of pressure causes the side wall to catastrophically collapse with the configuration of the cup-shaped member being inverted to permanently break the electric current path with a cover mounted terminal. A composite cover (8iv, 8v) includes a membrane layer in which the cup-shaped member is formed and which can also include a pressure vent (12g).

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 current interrupt mechanism for electrochemical cells is disclosed. A thermally activated current interrupt mechanism is integrated into an end cap assembly for an electrochemical cell. The thermally responsive mechanism preferably includes a free floating bimetallic disk which deforms when exposed to elevated temperature causing a break in an electrical pathway within the end cap assembly. This prevents current from flowing through the cell and effectively shuts down an operating cell. Alternatively, the thermally responsive mechanism may include a meltable mass of material which melts when exposed to elevated temperature to break an electrical pathway within the end cap assembly. The end cap assembly may also include integrated therein a pressure responsive current interrupt mechanism.

Abstract: A high speed analog signal sampling system. The system comprises a timing chain having a plurality of delay elements arranged in series and a sample rate multiplier having a delay lock control system responsive to the outputs of first, second and third parallel delay elements in the sample rate multiplier to control the delay of the second parallel delay element so that its strobe signal output occurs one-half the time between the strobe signal outputs of the first parallel delay element and the third parallel delay element. The first, second and third parallel delay elements are the first three parallel delay elements of the timing chain, and a control signal of the delay lock control system is used to adjust and control the amount of delay introduced by every other parallel delay element after the second parallel delay element.