摘要:
A method and apparatus adapted to calibrate a signal path of a signal analysis system such that loading effects of the system are substantially removed from measurements of a device under test. A signal under test from the device under test is coupled to a test probe in the signal path and used with selectable impedance loads in the test probe to characterize transfer parameters of the device under test. An equalization filter in either the frequency or time domain is computed from the device under test transfer parameters for reducing in signal error attributable to the measurement loading of the device under test.
摘要:
A new methodology for the measurement of the S-parameters of a high impedance probe allows obtaining a full two port S-parameter set for the high impedance probe. The measured probe S-parameters are then used for characterization of probes. An alternative method characterizes half of the fixture and termination as a one-port network and expanding it into a two-port error box. The two-port error box is then cascaded with the probe input.
摘要:
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.
摘要:
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 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. Changes in the polarization state of the optical signal attenuates the magnitude of the output electrical signal of the optical receiver.
摘要:
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.
摘要:
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.
摘要:
A attachable/detachable probing tip system (10) has a housing (12) that includes a probing tip mounting member (14) and opposing substantially orthogonal attachment (16, 18) arms extending from the probing tip mounting member. The attachment arms define an inner surface of the probing tip mounting member in which is disposed at least a first a non-compressive set, resilient member (56). First and second probing tips (42, 44) are disposed over the non-compressive, resilient member (56) and secured to the housing by latching means (60, 66, 92, 96, 100, 130). The attachable/detachable probing tip system allows mounting of the probing tips (42, 44) to probing contacts on a device under test without a probe body or probing tip member (38) being attached. The attachment arms (16, 18) allows a probe body or probing tip member (38) to be attached and detached to the probing tip system (10). The probing tip member (38) includes contact pins that engage contact areas (82, 82, 92) of the probing tips (42, 44).
摘要:
A high speed differential attenuator is formed on low temperature co-fired ceramic substrate structure having first and second parallel resistor-capacitor divider networks with each divider network having first and second parallel resistors and capacitors. The substrate has first and second dielectric layers with the top surface of the first dielectric layer having a voltage potential lead formed thereon for receiving an integrated circuit device. Each divider network further has first and second conductive elements formed on the top surface of the first dielectric layer functioning as first capacitive plates for the first and second capacitors. A third conductive element is disposed between the first and second dielectric layers and positioned beneath the first conductive element functioning as the other capacitive plate for the first capacitor. A fourth conductive element is disposed between the first and second dielectric layers and positioned beneath both of the second conductive elements of the divider networks and the voltage potential lead and functions as the other capacitive plate for the second capacitors of the divider networks and as a heat transfer layer. At least a first thermally conductive via is formed between the top and bottom surfaces of the second dielectric layer and below the voltage potential lead with the via thermally coupled to the fourth conductive element. The thermal via or vias may be thermally coupled to a heat sink disposed adjacent to the bottom surface of the second dielectric layer.
摘要:
A new methodology for the measurement of the S-parameters of a high impedance probe allows obtaining a full two port S-parameter set for the high impedance probe. The measured probe S-parameters are then used for characterization of probes. An alternative method characterizes half of the fixture and termination as a one-port network and expanding it into a two-port error box. The two-port error box is then cascaded with the probe input.
摘要:
A method and apparatus adapted to calibrate a signal path of a signal analysis system such that loading effects of the system are substantially removed from measurements of a device under test. A signal under test from the device under test is coupled to a test probe in the signal path and used with selectable impedance loads in the test probe to characterize transfer parameters of the device under test. An equalization filter in either the frequency or time domain is computed from the device under test transfer parameters for reducing in signal error attributable to the measurement loading of the device under test.