Abstract: A technique for measuring the current, voltage and phase of a Radio Frequency (RF) power wave to an RF load, accounts for the finite length of the voltage and current pickups, and corrects for effects of standing wave components of voltage and current. Voltage and current are computed as complex functions of the voltage pickup signal and the current pickup signal, based on coefficients precalibrated for the predetermined radio frequency. Alternatively, a corrected current value can based on the corrected voltage value and complex load impedance. The correction coefficients can be obtained, for each of a plurality of calibrating radio frequencies within an RF range, from voltage and current pickup signals under conditions of (a) open circuit load, (b) short circuit load, (c) fixed known impedance load; and (d) one of voltage and current being applied at a precise input level to a known load from an RF calibration source.

Abstract: The invention relates to a device (100, 200) for use in the detection of the power that passes through an electronic device, comprising means (110) for division of the power that enters the device into a first and a second branch. Each branch receives a predetermined proportion of the total input power with a predetermined phase difference between the signals that go into the branches, and the device comprises a first power detector (140) for the first branch and a means (130) for summation of the power in the two branches. The invention is characterized in that the device (100, 200) further comprises a second power detector (150) for the second branch, and in that the means (130) for summation can be controlled with regard to which branch and thereby to which power detector (140, 150) the sum of the power is diverted, and in that the device comprises, in one of its branches, means (120) for said control of the summator.

Abstract: The present invention provides an electromagnetic probe, comprising at least one assembly comprising in combination:

Abstract: An r.f. probed strain gauge is described. The strain gauge is in the form of an r.f. transmission line where electrical characteristics (r.f. impedance and propagation contrast) vary with strain in the element or structure whose strain is being measured.

Abstract: An apparatus, method and system extend the dynamic range measurements performed on a device under test. The apparatus and method compensate for the non-ideal characteristics of the measurement system elements. Further, the apparatus, method and system facilitate low-level distortion measurements and improve the accuracy of such measurements using a novel cancellation signal approach. The dynamic range extension apparatus has an input port for accepting an input test signal from a signal source and an output port for delivering an output signal to a measurement processor. The apparatus comprises a signal splitter at its input, a cancellation pathway, a test pathway and a signal combiner at its output. The system comprises a signal source that provides an input signal to the input of the apparatus and a measurement processor at the output of the apparatus. In the dynamic range extension apparatus, method and system, a signal from the input signal source is split by the signal splitter into two signals.

Abstract: There are provided electromagnetic wave source detecting apparatus and method as well as electromagnetic wave source analyzing system and method which can detect and analyze a source of (electromagnetic disturbing wave) representing a main factor in generating an electromagnetic field remotely of the apparatus in order to suppress the electromagnetic field intensity at the remote distance from the apparatus to below a regulated value.

Abstract: The present invention relates to a switched attenuator diode microwave power sensor and more particularly to a true average, wide dynamic range microwave power sensor utilizing a switched step attenuator on the sensor input. The present invention provides a sensor that uses a switched attenuator to always keep the signal to the sensor diodes in their “square law” region of operation has significant advantages over the prior art.

Abstract: A temperature compensated power detector generally comprises a detector circuit portion, which includes a detector diode, and a temperature compensation circuit portion, which includes a temperature compensation diode, that is operably connected to the detector circuit portion. The detector diode and the temperature compensation diode are connected in DC series with each other and develop substantially identical voltage drops. The detector circuit portion operates to detect a voltage from a power input. However, the detected voltage is subject to alteration due to temperature variations. The temperature compensation circuit portion develops a voltage that is also subject to alteration due to temperature variations. The temperature altered voltage of the temperature compensation circuit portion is used to cancel out the temperature altered voltage of the detector circuit portion allowing the power detector to produce a true voltage output.

Abstract: A board inspection probe for inspecting pattern lines on a circuit board for defects in a non-contact manner. The probe has an electrode for radiating an electrical signal or receiving an electrical signal radiated from a first pattern line. The probe also has a shield to prevent, from reaching the electrode, unwanted radiant waves emitted from pattern lines located in a region except a board region immediately below an electrode surface of the electrode. This shield is terminates near the electrode surface of the electrode, so that radiant waves from only pattern lines located on the board region immediately below the electrode are received.

Abstract: A power meter includes components to measure RMS power over an 84 dB range or greater using the I-V square-law relation of a diode for measurements. The power meter includes multiple diodes along with a power distribution manifold which includes power dividers to distribute an input signal to the diodes. In one embodiment, a first power divider (202) distributes power to a first one of the diodes (203), and to the second power divider (204) which distributes power to the second (210) and third (212) diodes. The first power divider (202) is connected without attenuation to the first diode (203). The second power divider (204) is connected to the second diode (210) through a 11 dB attenuator (206), and to the third diode (212) through a 28 dB attenuator (208).

Abstract: A system for sensing RF amplifier output power includes an amplifier transistor and two sampling transistors. The two sampling transistors are physically smaller than the amplifier transistor, and are preferably the same size. The first sampling transistor is configured to sample the same RF input signal that is amplified by the amplifier transistor. The second sampling transistor is configured to receive and amplify only a bias network signal. The bias network associated with the transistors includes a selection of components based upon operating parameters as well as actual physical sizes of the transistors. The selection of component values in association with transistor sizes is used to enable generation of a current sensing signal that is proportional to the power level of the RF output signal generated by the amplifier transistor.

Abstract: A receiver circuit, which may be used in a leakage detector, includes an RF input, a narrow band filter, and a direct demodulator. The leakage detector in which the receiver circuit may be used is operable to measure leakage in a communication system, the communication system operable to transmit broadband communication signals comprising one or more radio frequency carrier signals modulated by one or more baseband communication signals, wherein each radio frequency carrier signal has a channel frequency. Essentially, the exemplary receiver circuit according to the present invention is operable to generate a baseband leakage signal. To this end, the RF input is coupled to a source of broadband communication signals and receives a broadband communication signal therefrom, the broadband comnunication signal including a first signal associated with a first channel frequency.

Abstract: Disclosed are method and apparatus which measure signal level of an RF signal. The measured RF signal includes a baseband signal modulated onto a first carrier signal having a first frequency and the baseband signal includes program information and control information. The method and apparatus digitize the RF signal which includes the baseband control information and determine a signal level measurement from the baseband control information in the digitized RF signal. Furthermore, method and apparatus are disclosed which determine from the digitized RF signal whether a tagging signal is present in the RF signal.

Abstract: A system for sensing RF amplifier output power includes an amplifier transistor and a sampling transistor that is physically smaller than the amplifier transistor. The sampling transistor is configured to sample the same RF input signal that is amplified by the amplifier transistor. A bias circuit associated with the transistors includes a selection of components based upon operating parameters as well as actual physical sizes of the transistors. The selection of component values in association with transistor sizes is used to enable generation of a current sensing signal that is proportional to the power level of the RF output signal generated by the amplifier transistor.

Abstract: The present invention provides a true average wide dynamic range (TA-WDR) power sensor that can be used to make accurate power measurements from −70 dBm to +20 dBm or more (wide dynamic range), regardless of the format of the signal (true average). In one preferred embodiment, the present invention provides a true average wide dynamic range power sensor comprising an input for receiving RF signals having wide dynamic power ranges, a first RF path including a low power diode sensor for measuring RF signals having low power ranges, a second RF path including an attenuator high power sensor for measuring RF signals having high power ranges, and a switch for isolating the first RF path when the high power RF signals exceeds the square law region of the diode sensor.

Abstract: A dual mode power meter provides a first operation mode in the square law operating range of the diode, and a second mode in the square law region as well as the transition and linear operating ranges of the diode. The power meter includes multiple diodes. A manifold made up of power dividers distributes a signal input to the power meter to the diodes. A different attenuation is provided to each diode so that the square law operating range for each diode covers a different power range. By selecting the appropriate diode output for power measurements in the first mode, the overall square law operating range for the power meter will be greater than a power meter using a single diode. The power meter further includes a memory map of voltage vs. power in the square law, transition and linear regions of a diode measured for an unmodulated CW input for the second operation mode. The map of voltage vs.

Abstract: A system and method for detecting a location of an open circuit is disclosed. The open circuit is in a circuit of semiconductor device. The semiconductor device has a surface. The method and system include supplying alternating power to the semiconductor device and sensing a time-varying signal that is related to the alternating power. The method and system also include determining where the signal is substantially changed.

Abstract: A field sensor (1) comprising means for measuring a magnetic field and an electric field, wherein at least six capacitor plates (5, 6, 7, 15, 16, 17, 25, 26, 27, 35, 36, 37)are provided which are arranged in a cube and in that in the space thus formed the means for measuring the magnetic field is provided, which means is three-dimensionally aligned and for example consists of coils (2, 3, 4), Hall-effect sensors, magnetoresistors or the like.

Abstract: The invention provides a true average, wide dynamic range microwave power sensor using a diode-stack-attenuator diode stack technology. The invention provides a diode stack microwave power sensor which includes an RF signals receiver having wide dynamic power ranges; a low power sensor path connected between the receiver and ground for sensing relatively low power RF input signals. The low power sensor path includes one or more stacked RF diodes in which a number of diode pairs may be coupled to ground through respective capacitors. An impedance network including attenuating resistors R1 and R2 are connected in series between the receiver and ground. A high power sensor path is connected in parallel between the attenuating resistors R1 and R2 and ground for sensing attenuated relatively high power RF input signals.

Abstract: A probe (10) has a main body (12), an input side (14) and an output side (16). The main body (12) has a cavity (17) to receive an insulator (18). The insulator (18) has a current slit (22) and a voltage slit (24) aligned with a first aperture (30a) and a second aperture (30b). An inner conductor extends through the insulator (18) from the input side (14) to the output side (42) of the main body (12). A current sensor (40) inserts into the first aperture (30a) and the current slit (22). A voltage sensor (50) inserts into the second aperture (30b) and the voltage slit (24). A radio frequency signal on a transmission line having a same impedance as the probe (10) enters the inner conductor (20) at the input side (14), induces a current onto the current sensor (40) and a voltage onto the voltage sensor (50). The induced current and voltage can be measured to monitor the characteristics of the transmission line.

Abstract: A hand held detection device for detecting electromagnetic waves at at least one predetermined frequency has an elongated conductor member having a bottom end portion for grasping by a hand of a user and a top end portion, the elongated conductor is configured to function as an antenna at the predetermined frequency. An inductor is supported on and electrically connected to the top end portion of the elongated conductor. A wave detection circuit is supported at the top end portion of the elongated conductor member one the inductor. The wave detection circuit includes a rectifier diode for rectifying high-frequency alternating current received in the inductor via the elongated conductor to produce a direct current. The wave detection circuit also includes an indicating means for indicating a presence of a direct current produced by the rectifier diode, the indicating means and the rectifier diode are serially connected to form a series circuit, and the series circuit is connected across a portion the inductor.

Abstract: A photonic radio-frequency (RF) field probe for detecting and measuring RF fields incorporates a probe head, a fiber cable and a photodetector/power-laser unit. An antenna drives a small, fiber-coupled laser, biased by a fiber-coupled optical power converter through series resistors, together with electrical connections and supporting apparatus. Methods of calibration include use of a reference oscillator in the probe head, use of the relationship between optical power sent to the optical power converter and resulting photodetector signal, and measurement of signal-fiber attenuation from light reflected by the laser in the probe head. Other probe embodiments utilize a reflective multiple quantum well modulator and embodiments which measure all three directional components of the RF field.

Abstract: A board inspection probe for inspecting pattern lines on a circuit board for defects in a non-contact manner. The probe has an electrode for radiating an electrical signal or receiving an electrical signal radiated from a first pattern line. The probe also has a shield to prevent, from reaching the electrode, unwanted radiant waves emitted from pattern lines located in a region except a board region immediately below an electrode surface of the electrode. This shield is terminates near the electrode surface of the electrode, so that radiant waves from only pattern lines located on the board region immediately below the electrode are received.

Abstract: A circuit for determining power changes in an RF circuit includes first and second temperature sensitive resistors connected in parallel with an RF input terminal so as to have a common junction therewith. The first resistor has a positive temperature coefficient of resistance and the second resistor has a negative temperature coefficient of resistance. A DC input terminal is connected to one of the temperature sensitive resistors and an output terminal is connected to the common junction of the two temperature sensitive resistors. Third and fourth temperature sensitive resistors have a common junction. The third resistor has a positive temperature coefficient of resistance and the fourth resistor has a negative temperature coefficient of resistance. The DC input terminal is also connected to one of the third and fourth temperature sensitive resistors, and an output terminal is connected to the common junction of the third and fourth temperature sensitive resistors.

Abstract: Noise detection devices are placed at arbitrary measurement points. A selection device switches the output of the noise detection devices and an analyzer analyzes the noise amount of the frequency component for each frequency band of radiated noise. A comparison device is made up of a storage section for storing measurement data provided by a plurality of the detection devices and a comparator, and finds a difference and a greater-than, equal-to, or less-than relationship between the noise amount analyzed by the analyzer and a predetermined value in a full band or at a specific frequency or a difference and a greater-than, equal-to, or less-than relationship between the noise amounts at two points. Output of the comparison device is displayed on a display device.

Abstract: Magnetic sensors are positioned adjacent a semiconductor integrated circuit under test while the circuit is subjected to selected electrical stimuli for purposes of failure analysis. The magnetic image data can be acquired from one or more selected locations about the circuit without any physical connection. By comparing the magnetic sensor information to a predetermined database of magnetic information acquired from known devices, failure modes can be identified. Conventional tester equipment can be used for providing the electrical stimuli to the device under test.

Abstract: The invention relates to a temperature sensing system that accurately measures temperatures of articles or areas using a contact sensor even in a high radio frequency environment. The temperature sensing system includes a sensor probe that contacts with an article or area that is to have its temperature monitored, and a control circuit to amplify signals from the sensor probe. When significant amounts of radio frequency (RF) interference are present, the temperature sensing can be provided with RF shielding, RF filtering, isolated amplifying and/or multiple stages of low pass filtering that suppress the RF interference. The temperature sensing system is particularly well suited for monitoring and measuring temperatures within semiconductor manufacturing equipment, such as etching, deposition, and other processing chambers.

Abstract: A hand held detection device for detecting electromagnetic waves at at least one predetermined frequency has an elongated conductor member having a bottom end portion for grasping by a hand of a user and a top end portion, the elongated conductor is configured to function as an antenna at the predetermined frequency. An LC-resonance circuit is supported on and electrically connected to the top end portion of the elongated conductor and the LC-resonance circuit is tuned for accepting the at least one predetermined frequency. A wave detection circuit is supported at the top end portion of the elongated conductor member. The wave detection circuit includes a rectifier diode for rectifying high-frequency alternating current received in the LC-resonance circuit via the elongated conductor to produce a direct current.

Abstract: A detector facilitates visualization of electromagnetic radiation, including radio frequency radiation. The electromagnetic radiation is converted to thermal energy by partial absorption of the radiation, and is made visually observable by coupling the pattern of thermal energy to a thermally-responsive imaging surface, such as a liquid crystal display.

Abstract: The present invention provides a detector comprising a microstrip line having one end being grounded and another end connected to a main transmission line, a detection diode connected to the microstrip line, and a smoothing circuit for smoothing a signal detected by the detection diode.

Abstract: A calorimetric wattmeter for testing a microwave oven. The wattmeter comprises a housing which defines an interior chamber for holding a quantity of a microwave absorbing liquid. Attached to the housing is a thermometer having a sensor portion which extends into the interior chamber and an indicator portion which moves in response to temperature changes sensed by the sensor portion. Additionally, rotatably attached to the housing is a scale which circumvents the indicator portion and includes indicia thereon for correlating the position of the indicator portion to a microwave oven wattage reading. The scale is selectively rotatable for purposes of resetting the microwave oven wattage reading to zero relative to the position of the indicator portion. The housing also includes a pair of neon gas filled enclosures attached thereto for providing a visual indication of the presence of microwaves.

Abstract: A cable leakage detection system to be placed in a moving vehicle for monitoring signals leaking from a coaxial cable network. AM and FM RF detectors are combined with a global positioning system, a microprocessor, a storage device, a display device, and an antenna to unambiguously measure the radio frequency signal strength of an RF leak. The leakage detection system can indicate whether the leak is occurring in the left or right side of the vehicle. An operator can, by observing the unique display, determine whether the received RF energy is a leak from the coaxial cable system or a spurious signal from some other source. The cable leakage detection system can unambiguously detect an RF leak and store the vehicular leakage index, the RF signal level, the distance from the coaxial cable, the frequency of the signal, the geographic location, and the time of the detected leak.

Abstract: An RF circuit for use as a front end for a combined leakage signal detector and signal level monitor includes a shared frequency conversion stage utilized for both leakage signals and signal level monitoring ("SLM") signals. One embodiment of the present invention includes an RF circuit comprising a first RF input, a second RF input, a frequency conversion circuit and a coupling device. The first RF input is operable to receive first signals to be monitored, the first signals being in a first frequency range. The second RF input is operable to receive leakage signals to be detected, the leakage signals also being in a first frequency range. The frequency conversion circuit is operable to convert signals in the first frequency range to signals in a second frequency range, the frequency conversion circuit operable to receive unconverted first signals and unconverted leakage signals and produce output signals therefrom.

Abstract: An EM radiation measuring apparatus. An antenna element matrix (20) on a substrate includes 1st to Lth arrays (4) which are successively arranged in an X direction. Each of the 1st to Lth arrays includes antenna elements arranged in Y direction and having a column output terminal (7), each antenna element receiving an EM radiation from a target and generating a detection signal. A signal selector (5, 3, 2, 7) responsive to X and Y selection signals selectively amplifies and supplies the detection signal from one of antenna elements to one of the column output terminals. 1st to Nth signal outputting circuits selectively couple the column output terminals to provide a single output detection signal. The inputs of the 1st signal outputting circuits are connected to the column output terminals respectively, and each of the 1st to Nth outputting circuits has a transmission line(s) substantially extending in the X direction to connect its output terminals to an input of the next outputting circuit.

Abstract: An EM radiation measuring apparatus comprises an antenna element matrix on a substrate including 1st to Lth arrays which are successively arranged in an X direction, each of the 1st to Lth arrays including antenna elements arranged in a Y direction and having an output terminal, each antenna element receiving EM radiation from a target and generating a detection signal. A signal selector responsive to X and Y selection signals, selectively supplies the detection signal from one of antenna elements to one of the output terminals. 1st to Nth signal outputting circuits, each having inputs, at least an output, and at least a signal selection circuit selectively coupling the inputs to the output terminals of which the number is less than the number of the inputs.

Abstract: Apparatus for directly measuring the value of a component within an RF circuit (e.g., an RF matching network within a semiconductor wafer processing system). Specifically, the apparatus applies a low frequency signal (e.g., a 1 KHz) across one or more of the components within an RF circuit using a bridge circuit that is sufficiently isolated from the RF signal to accomplish accurate measurements of the component. The apparatus monitors the amplitude of the low frequency signal across the component. The amplitude of the low frequency signal is indicative of the value of the component.

Abstract: An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

Abstract: An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

Abstract: An apparatus for sensing RF current delivered to a plasma includes an RF conductor along which the current is delivered to the plasma and which is divided into two parts along part of its length so that substantially equal currents flow in each part. A sensor device is inserted into the gap between the two parts of the conductor and includes first and second inductive loops disposed one on each side of the gap such that when an RF current flows along the RF conductor the magnetic flux surrounding the conductor which is generated by the RF current couples with the loops respectively in opposite directions relative to the sensor device. If a stray magnetic flux normal to the current direction couples with the loops in the same direction relative to the sensor device it will induce voltages in the loops which respectively add to the voltage induced by the RF current in one loop and subtract from the voltage induced by the RF current in the other loop.

Abstract: A method for operating a TEM cell to determine the characteristics of a radiation source in a circuit. The circuit is placed in the TEM cell such that the relative orientation of the circuit and the TEM cell is measurable. The TEM cell provides an output signal indicative of the energy radiated by the circuit when the circuit is operated in the TEM cell. The output signal of the TEM cell is measured for at least 6 different relative orientations of the circuit and the TEM cell. The electric and magnetic dipole moments of a radiation source having an orientation and physical dimension associated therewith are determined from the measured output signals. The electric and magnetic dipole moments determined from the measured output values are compared to moments predicted by each of a plurality of antenna types to provide an estimate of the orientation of the radiation source relative to the circuit.

Abstract: A device for measuring the microwave power produced by a microwave oven so as to determine whether the oven is producing its rated or set power, to prevent inadvertent undercooking of food, includes a calorimeter employing tap water as a working medium and a thermometer that can be set initially to read zero for any initial temperature of the working medium. In accordance with the invention, an enclosure containing a quantity of gaseous neon is connected to the calorimeter, and the gaseous neon glows only when radiation is present. The actual irradiation time, which may be less than the set cooking time due to start-up delay, may be accurately determined by timing the duration of the neon glow as observed through the window of the oven.

Abstract: The invention relates to a directional coupler arrangement and measurement of radio frequency electric power with a directional coupler arrangement, which arrangement comprises a directional coupler, in which a terminal impedance, a detector element and a control circuit are connected between the end of the second conductor element and the earth potential. The impedance value of the terminal impedance can be altered by means of an electric control signal and said control circuit produces said control signal on the basis of the signal provided by the detector element. When the detected power level is low, the control circuit increases the impedance value of the terminal impedance, whereby the peak voltage of the signal applied to one end of the directional coupler increases and the arrangement yields a measurement result that is larger than ordinary, which improves the accuracy and reliability of the arrangement at low power levels.

Abstract: An electromagnetic radiation measuring device includes a plurality of antenna elements arranged in a matrix. Each antenna element includes an insulator having a substantially rectangular parallelepiped shape, supporting at least one conductor pattern. The first and second ends of the conductor pattern are connected to first and second print patterns on a printed circuit board. A detection signal is selectively provided by a switching device from at least one conductor pattern of each antenna element.

Abstract: In apparatus for measuring the output power an RF transmitter stage (34) connected to an antenna (44) via a quarter wavelength stripline (38), a manual probe (20) is applied connect the output of the transmitter stage to a power meter (24) and connect the output end of the stripline (38) to ground. Thus, RF signals which were passed to the antenna (44) are switched to the power meter (24). All the circuitry including the antenna (44) is mounted on a printed circuit board (60) disposed within a housing (14) which has an aperture (18) to enable the probe (20) to be inserted. By providing a suitable meter, parameters other than RF power can be measured.

Abstract: A control circuit which regulates an ac power output device. The control circuit is operatively connected to the ac power output and measures the ac signal with a diode to generate a control signal stimulus. A second diode is operatively connected to the power measuring diode so that the two diodes have the same voltage drops associated with the quiescent operation of the diodes. Quiescent voltage changes in the power measuring diode are canceled by the matching quiescent voltage change in the second diode. In this manner, power measurement errors associated with diode quiescent voltage changes are minimized.

Abstract: An electromagnetic radiation monitor for use in close proximity with the human body comprised of an electromagnetic radiation sensor for detecting hazardous radiation levels. The radiation monitor also includes means for shielding the sensor from electromagnetic interference caused by the human body. A single layer of a plurality of lossy materials arranged in a precise, predetermined mosaic pattern is used in conjunction with a shield to prevent interference due to unwanted reflections caused by the shield resulting in a wideband frequency response previously unachievable.

Abstract: The effects of differential heating inside the calorimetric bridge are reduced by first heating the bridge externally and controlling the resulting temperature. The bridge is also heated internally by an amount that varies according to the applied power to be measured. This acts to eliminate the principal source of thermal gradients in the first instance. By applying this heat as a common mode input signal to the two terminating loads of the calorimetric bridge the bridge itself does not become unbalanced, and therefore does not attempt to measure that common power. Actual input power to be measured does initially unbalance the bridge, and is still measured as usual. A constant power circuit is response to the indication of measured power and acts to keep the sum of measured power (plus the equal amount of feedback power that balances the bridge) and the common mode power at a constant value corresponding to a full scale measurement.

Abstract: An economical, wide range and accurate power measurement technique switches an RF detector between an applied RF IN to be measured and a COMPARISON RF IN, to thus develop a difference signal. The difference signal is filtered, amplified by a logarithmic amplifier, and then converted into a DC error signal by a synchronous detector operating in step with the switching of the RF detector. The DC error signal is applied to an integrator whose output is a loop control signal. Assuming a square law detector, the square of the loop control signal is linearly proportional to the applied RF IN once a servo loop is hulled by making COMPARISON RF IN equal to RF IN. The desired power measurement is performed by digitizing the loop control signal and performing the appropriate arithmetic operations thereon. The loop control signal is also applied to an analog multiplier, where it combines with an internal RF reference signal to produce, at the output of an attenuator following the multiplier, the COMPARISON RF SIGNAL.

Abstract: A combined signal level meter and leakage detector having a built-in antenna for the leakage detector, and dual clock frequency control of the microcontroller along with bandwidth switching for greater sensitivity in leakage detection mode. A data logging function is also provided. Control circuitry is also provided for avoiding receiver spurs by combined switching of multiple local oscillator frequencies, including combinations of high-side and low-side injection and IF shifting.

Abstract: The performance of a device under test is observed with and without the presence of controlled EMI fields. Voltage signals from the device under test are transmitted to an oscilloscope by overdamped conductors, a hybrid electrical/optical transmitter, a fiber optic cable, a receiver and a conductor cable. The overdamped conductors are transparent to the EMI fields and the current in those conductors is kept very small by the use of a very high input impedance in the transmitter. The hybrid transmitter may be an analog or a digital transmitter.