Abstract: An acoustic damping material for electro-optic material has an adhesive material combined with a ceramic crystalline material such that the acoustic impedance of the combined adhesive material and the ceramic crystalline material is substantially the same as the acoustic impedance of the electro-optic material.

Abstract: A lumped resistance electrical cable has a multiple twisted pair ribbon cable having first and second conductive lines and twisted and untwisted portions. In the untwisted portions, one of the conductive lines on each of the twisted pairs is formed with an electrical open. Resistor blocks having resistive elements and electrical contacts is disposed on the untwisted portions with the electrical contacts electrically coupling the resistive elements across the electrical opens in the conductive lines. Other electrical contacts in the connector couple the other conductive lines of the twisted pairs to an ground plane formed on the resistor block.

Abstract: A current sensing circuit has a transformer where a current to be measured induces a magnetic flux into a magnetic core. The magnetic core has a magneto-electric converter for sensing DC to low frequency current signals and a secondary winding for sensing higher frequency current signals. The magneto-electric converter generates an output that is coupled via an amplifier to a non-inverting input of a transimpedance amplifier. The inverting input of the transimpedance amplifier is coupled to the secondary winding of the transformer. A current signal path having a transimpedance resistor couples the inverting input to the output of the transimpedance amplifier. The transimpedance amplifier functions as a power amplifier for coupling a nulling current to the transformer for DC to low frequency current signals and functions as a transimpedance gain amplifier for higher frequency signals.

Abstract: A variable attenuation signal acquisition probing system and voltage measurement system uses an optical cavity to acquire a signal under test. The probing system has an optical transmitter and receiver that are coupled to the optical cavity via an optical transmission system. The optical cavity has an electrode structure having apertures formed in the optical cavity that are parallel to propagation path of the optical signal within the cavity. A modulated optical signal is generated by the optical cavity in response to the signal under test creating an electromagnetic field distribution in electro-optic material in the optical cavity that overlaps the optical path of the optical signal propagating in the optical cavity which varies the index of refraction of electro-optic material in the optical path. Changes in the polarization state of the optical signal attenuates the magnitude of the output electrical signal of the optical receiver.

Abstract: A communications bus management circuit for a current probe system detects the connection of the current probe system to an instrument and the connection of a current probe to a current probe amplifier of the system. A controller generates a probe enable signal in the presence of the detected connection to the instrument that is coupled to a switching circuit. Switch elements couple the communications bus of the instrument to the communications bus of the current probe amplifier in the presence of the probe enable signal. The controller further generates a current probe present signal in the presence of the detected current probe that is also coupled to the switching element. A further switch element couples the data line of the instrument to ground via a resistive element in the presence of the current probe present signal and floats the data line when the current probe present signal is absent.

Abstract: A multiband amplifier for a test and measurement instrument includes a splitter to split an input signal into split signals, amplifiers, and means for combining and digitizing the amplified signals into a digitized signal. Each amplifier is configured to amplify an associated split signal over an amplifier passband. The amplifier passband of at least one amplifier is different from the amplifier passband of another amplifier.

Abstract: A triggered data generator reduces timing jitter at the start of serial data output from arrival of a trigger signal. A trigger detecting circuit 8 produces trigger phase information indicating the phase relationship between the trigger signal and a reference clock. A data pattern generating circuit 10 generates parallel data bits according to the reference clock in response to the trigger signal. A data shifting circuit 11 rearranges the parallel data bits in a predetermined order to produce shifted parallel data bits in which data bit order is shifted relative to the reference clock as a function of the trigger phase information. A parallel to serial converter 16 converts the shifted parallel data bits into serial data bits.

Abstract: A current probing system has a current probe and a detachable adapter. The current probe has a probe body with electrically conductive contacts that mate with electrically conductive contacts on the adapter. Leads extend from the adapter for coupling to a current carrying conductor. The leads can connect to a plug that is coupled to a current diverting device for coupling a current signal to the current probe. The adapter may also include a switch that selectively couples the current signal to the current probe when the adapter is mated with the current probe. The contacts of the current probe are coupled to a current sensing circuit which generates a voltage output representative of the current signal. The voltage output is coupled to an oscilloscope via an electrical cable.

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 wide bandwidth attenuator input circuit for a measurement probe has a Z0 attenuator circuit coupled in series with a compensated RC attenuator circuit. The series attenuator elements of the Z0 and the compensated RC attenuator circuits are coupled via a controlled impedance transmission line to the shunt attenuator elements of the Z0 and the compensated RC attenuator circuits. The shunt element of the Z0 attenuator element terminates the transmission line in its characteristic impedance. The junction of the series and shunt attenuator elements are coupled to the input of a buffer amplifier. At low and intermediate frequencies, the compensated RC attenuator circuit attenuates an input signal while at high frequencies, the compensated RC attenuator circuit acts as a short and the Z0 attenuator circuits attenuates the input signal.

Abstract: A measurement probe has a spring loaded probe assembly and a pressure sensor disposed in a housing. The pressure sensor forms an electrical switch for passing an activation signal to a EOS/ESD protection module in response to axial movement of the housing relative to the probe assembly. A first compressive element produces a first pre-loaded compressive force and an increasing compressive force on the probe assembly and a second compressive element produces a second pre-loaded compressive force and an increasing compressive force on the probe assembly subsequent to the first increasing compressive force.

Abstract: An optically pumped micro-cavity laser has an optical gain cavity and an optical resonant cavity. The optical gain cavity has a gain medium disposed that generates an optical output in response to an optical pump signal. The optical resonant cavity has an electro-optic material in which is disposed an electrode structure with first and second apertures disposed generally parallel to an optical signal propagating within the electro-optic material. Electrically conductive material is disposed within the apertures coupling an electrical signal to the optical cavity. Optically reflective material is disposed on the opposing surfaces of the micro-cavity laser and between the optical gain cavity and the optical resonant cavity.

Abstract: A signal acquisition probing system uses an optical cavity to acquire a signal under test. The probing system has an optical transmitter and receiver that are coupled to the optical cavity via an optical transmission system. The optical cavity has an electrode structure having apertures formed in the optical cavity that are parallel to propagation path of the optical signal within the cavity. A modulated optical signal is generated by the optical cavity in response to the signal under test creating an electro-magnetic field distribution in electro-optic material in the optical cavity that overlaps the optical path of the optical signal propagating in the optical cavity which varies the index of refraction of electro-optic material in the optical path. The signal acquisition probing system is connected to a measurement instrument to form a voltage measurement system.

Abstract: A variable persistence waveform database is generated by defining a First-In-First-Out (FIFO) time-ordered queue buffer for maintaining a selected number of waveform records. Digital data samples of a measurement signal are acquired and stored in a plurality of waveform records in the FIFO time-ordered queue buffer. Counts of the digital data samples for the plurality of waveform records are accumulated in a waveform database. Upon filling FIFO time-ordered queue buffer with waveform records, the digital data samples of the oldest acquired waveform record are subtracted from the accumulated counts of the waveform database and deleted from the FIFO time-ordered queue buffer and the digital data samples of the newest acquired waveform record are stored in the FIFO time-ordered queue buffer and added to the accumulated counts in the waveform database.

Abstract: A pulse delay circuit induces lager jitter to faster input reference pulse trains than before. A buffer receives a reference pulse train and provides non-inverted and inverted pulses. Low pass filters (LPF) and comparators receive the non-inverted and inverted pulses from the buffer and provide pulses having delayed leading and trailing edges. Dividers divide the delayed pulses by 2 to produce the respective pulse trains having a half frequency. An XOR gate produces an exclusive OR of the delayed and divided pulse trains to provide a pulse train having delayed leading and/or trailing edges relative to the reference pulse train. If the delays by the LPFs and comparators are changed, the output pulses from the XOR gate have jitter.

Abstract: A signal acquisition probing system uses a micro-cavity laser to acquire an electrical signal from a device under test. The micro-cavity laser has a VCSEL gain medium and an electro-optic optical resonant cavity. The micro-cavity laser is pumped by an external laser source and generates a frequency modulated optical signal derived from the device under test electrical signal creating an electro-magnetic field distribution in electro-optic material in the micro-cavity laser that overlaps the optical path of the optical signal propagating in the electro-optic material. The frequency modulated optical signal is coupled to an optical receiver which converts the frequency modulated optical signal to an electrical signal. The electrical signal is coupled to measurement test instrument for processing and displaying of the electrical signal.