Abstract: In one aspect, a method of radar altimeter operation including a time dependent gain control is described. The method comprises triggering a Sensitivity Time Control (STC) gain control signal at a pulse repetition frequency (PRF) of a transmit pulse to attenuate interference from at least one of an antenna leakage signal and a signal reflected from equipment. The method also includes shaping the STC gain control signal from no attenuation at a first time, before a transmitter sends the transmit pulse, to a stable maximum attenuation at the time the transmitter sends the transmit pulse, to no attenuation at a second time, after the transmitter sends the transmit pulse. The method also includes matching a bandwidth of an intermediate frequency (IF) amplifier to the pulse width of a transmitted pulse.

Abstract: A wireless communication system includes a transmitter comprising a serial-to-parallel converter for converting serial data bits to a parallel bit stream, a signal mapper coupled to the serial-to-parallel converter and an antenna selector coupled to the serial-to-parallel converter. The signal mapper receives as input a first group of bits from the parallel bit stream, and maps the first group of bits to a channel symbol. The antenna selector receives as input a second group of bits from the parallel bit stream. A transmit antenna array is coupled to the antenna selector and to the signal mapper. The transmit antenna array generates a plurality of transmit antenna patterns with one of the transmit antenna patterns being selected for transmitting the channel symbol based upon the second group of bits from the antenna selector.

Abstract: A calibration system for the receiver of a dual polarization radar system has been developed. The system includes a radar transmitter that transmits signals in horizontal and vertical polarizations and a radar receiver that receives the horizontal and vertical polarization signals. The system also includes a test signal generator that generates a continuous wave test signal. A calibration circuit for the radar receiver modifies the test signal to simulate weather conditions by adjusting the attenuation and Doppler phase shift of a continuous wave test signal.

Abstract: A system for simultaneously propagating dual polarized signals in a polarimetric radar system includes a system for shifting the phase of one of the two signals. The simultaneous dual polarization weather radar transmits signals in both the horizontal and vertical orientations at the same time. Upon reception, the signals in each channel are isolated and a number of standard and polarimetric parameters characterizing atmospheric conditions are determined. The accuracy upon which these parameters can be determined depends partially upon the interference between these two channels. The system and method isolates the vertical and horizontal channels by using the phase information from the signals to minimize the interference.

Abstract: A transmit signal is output from a transmitter towards a target and towards interference. A combination signal is received at a receiver, wherein the combination signal includes the transmit signal modified by interacting with the target and the interference along with noise. The receiver has a filter having a transfer function and the filter acts on the combination signal to form a receiver output signal having a receiver output signal waveform. The receiver output signal has a receiver output signal waveform that describes an output signal to interference to noise ratio (SINR) performance. Bandwidth and signal energy of the transmit signal are reduced simultaneously by modifying the transmit signal waveform and receiver output signal waveforms without sacrificing the output SINR performance level.

Abstract: Detection of failure mode peculiar to a high-electron mobility transistor is available. A control circuit controls a gate voltage switching portion so that the gate voltage applied to a transistor may become a given checking voltage. The checking voltage may be set to a pinch-off-voltage of the transistor, for example. The control circuit detects a current value of the drain current flown when the checking voltage is applied, thereby detecting a failure of the transistor based on the current value. According to the present invention, since failure detection is made on the basis of the drain current value flown when the checking voltage set up apart from an operating voltage is applied as the gate voltage, failure mode which is peculiar to the high electron mobility transistor and which is hardly detectable in an ordinary operating state becomes detectable.

Abstract: In a radar system installed in a vehicle, a first measuring unit measures a first physical relationship between the vehicle and a first object based on a received first echo signal A second measuring unit measures a second physical relationship between the vehicle and a second object based on a received second echo signal. A failure detector detects whether a failure occurs in each of the first and second measuring units. When it is detected that a failure occurs in one of the first and second measuring units, an alternative control unit causes the other of the first and second measuring units to serve as an alternative to the one of the first and second measuring units to thereby measure a corresponding one of the first and second physical relationships.

Abstract: A time-reversal imaging radar system for acquiring an image of a remote target includes an antenna array having a plurality of spaced-apart antennas, and a transceiver coupled to the antenna array for alternately transmitting a radar signal via the antenna array toward the target and for receiving target-reflected radar signals. The transceiver includes means for multiple-pass time-reversing the transmitted and received radar signals whereby coherent beam focusing is realized at both the target and at the receiver to thereby enhance the resolution of the acquired target image.

Abstract: A radar apparatus including units for transmitting and receiving an electric wave to detect a target, a unit for detecting wave interference caused by surroundings, a unit for controlling the modulation state of the transmitted wave, a communication unit for acquiring modulation state information being used by the other radar apparatuses, and a unit for selecting such a modulation state as to avoid interference with the modulation state information when the wave interference detecting unit detects the wave interference.

Abstract: Circuitry is provided to drive a step recovery diode (SRD) (8) in a sampler based vector network analyzer (VNA) that allows harmonic samplers (10, 11) to operate over many octaves. The circuit includes a digital pulse generator (FIG. 5) for providing a LO signal. The LO signal is provided over an octave frequency range as in previous SRD driver circuits, but pulse forming circuitry is provided to decrease the pulse rate to a sub multiple of the LO generating oscillator signal. The pulse forming circuitry includes a programmable frequency divider (50) to vary the pulse rate. The pulse forming network further includes registers (50, 52) connected to the programmable frequency divider (50) to limit the pulse width resulting in reduced heating of the SRDs. With an effectively wider frequency operation range using the SRD (8), only one downconversion is required in the VNA, eliminating the need for additional mixers (30, 31) and a second LO signal generator (24) to provide a second downconversion.

Abstract: A device for generating high powered Radio Frequency (RF) or microwave signals comprising a fast rise-time video pulse generator, a modulator to modify the generated UWB pulses by gyromagnetic action to transfer a portion of the UWB pulse energy from lower frequencies to frequencies in the RF or microwave range thereby producing a resultant RF or microwave waveform that can be radiated.

Abstract: A radar system array antenna includes plural elements. Each element is coupled to a port of a transmit-receive device. Digital data representing the characteristics of the radar signal is applied to a monolithic IC combination DAC/ADC, which converts the digital data into analog transmit signal. The analog transmit signal is applied to a monolithic microwave IC transceiver, which may be monolithic with the DAC/ADC. The transceiver upconverts the transmit signal. The upconverted transmit signal is applied to a transmit port of the transmit-receive device and transmitted. Receive RF signal is coupled from each antenna element through the transmit-receive device to a receive signal port of the transceiver. The transceiver downconverts the receive signal to produce received downconverted signal. The downconverted signal is coupled to the ADC part of the DAC/ADC, which converts to receive digital signal. Digital processing processes the receive digital signal to produce the return target information.

Abstract: A method and system are disclosed where transmitted radar pulses are utilized for both a radar sensing function and for data communications. The data communications are performed in a manner that is simultaneous and transparent to the radar sensing function, in terms of non interference or interruption. The method and system are applicable to data communications between multiple pulsed radar devices as well as radar devices that are capable of receiving pulsed transmissions and transmitting continuous wave transmissions.

Abstract: Provided is a pulse radar system capable of measuring the distance to an obstacle with high accuracy irrespective of the distance to an obstacle by securing distance resolution with respect to a reflective wave from an obstacle at a short distance, and preventing a decline in S/N ratio with respect to a reflective wave from an obstacle at a long distance. A pulse radar system includes a transmitting circuit, a transmitting antenna, a receiving antenna, a receiving circuit, and a gain control circuit. The gain control circuit generates a gain control signal corresponding to the amplitude of the reception pulse obtained in response to a gain control transmission pulse wave transmitted from the transmitting circuit, and controls the gain of a reception pulse wave or a reception pulse obtained in response to a measurement transmission pulse wave transmitted from the transmitting circuit after the gain control transmission pulse wave.

Abstract: An electric wave transmitting/receiving module includes: a waveguide including a conductive member and an opening facing a transmitting side and/or a receiving side; a dielectric substrate disposed on a side opposite to the opening of the waveguide; and transmitting/receiving means. The transmitting/receiving means includes a core line, a transmitting/receiving element, and a wire. The core line and the transmitting/receiving element are horizontally disposed on the dielectric substrate. The core line transmits the transmitting electric wave and/or receives the receiving electric wave. The transmitting/receiving element outputs a transmitting/receiving signal corresponding to the transmitting electric wave and/or the receiving electric wave. The wire sends the transmitting/receiving signal from the transmitting/receiving element to an external circuit.

Abstract: A level measuring instrument has a variable transmitting power for measuring a filling level in a tank. The level measuring instrument includes a generator unit selectively generating different transmitting powers. The generator unit is controlled so that the transmitting power is respectively adapted to the corresponding environmental conditions. For this purpose, the generator unit has for instance two different oscillators, which are driven selectively.

Abstract: The present invention provides a radio signal radiation system that alleviates the necessity of a highly specified pass band reception filter and a high performance/reliability amplifier. The radio signal radiation system includes an optical modulator; a light source for inputting an optical carrier wave into the optical modulator; a power source for applying a modulating signal having a frequency Fm on the optical modulator to superimpose a sideband wave onto the carrier wave, the modulating signal having an amplitude of N-times the drive voltage of the optical modulator; a light receiver to receive and convert the outgoing light into an electrical signal; and a radiating means for radiating a radio signal based on the electrical signal, wherein the sideband wave is superimposed at a position shifted by n×fm.

Abstract: A transmitting-receiving module of a radar system which is an embodiment of the present invention, includes, a transmitting circuit for sending transmitting RF signal, a three terminal circulator having three terminals and with the first terminal of which is connected a transmitting-receiving antenna, a first RF switch which is connected with the second terminal of the three terminal circulator and the output can be switched over, a second RF switch with input which can be switched over, an attenuator connected between the first RF switch and the second switch, and a receiving circuit connected with the output terminal of the second RF switch, when radar signal is being transmitted, the first RF switch is connected with the attenuator, and the second RF switch is not connected with the attenuator, when radar signal is being received, the first RF switch is connected with the second RF switch directly or connected through a low noise amplifier.

Abstract: A weather radar system includes processing electronics. The processing electronics sense weather and determine significant weather based upon the altitude of the weather. The altitude of the weather can be compared to a flight path to determine its significance. A display can provide visual indicia of the significant weather in response to the processing electronics.

Abstract: An adaptive broadcast radar system for tracking targets is disclosed. The radar system includes a transmitter having sub-apertures and a receiver having sub-apertures. The transmitter sub-apertures generate and code a signal waveform. The signal waveform is coded with data about the transmitter, including the degrees of freedom. The receiver receives signals that may include direct path signals and scattered signals correlating to the signal waveforms from the transmitter. The receiver includes a signal processor that regenerates a transmit beam for the coded data, delay, and doppler information from the received signals. The signal processor data quads encapsulates the information.

Abstract: A data code generator produces a data code, while a reference code generator produces a reference code. The data code is phase-shifted by the data code generator in a predetermined sweep range, according to a sweep command signal given by a phase difference detector. The phase difference detector compares the phase of the data code with that of the reference code to obtain phase difference data. Based on the phase difference data, a correction signal generator produces a correction signal to keep the data code in phase with the reference, code. The phase setter optimizes the phase of the data code according to the correction signal.

Abstract: On/off timing of an amplifier and timing of antenna selection are accurately adjusted. When adjusting the on/off timing of the amplifier, modulation of a transmit signal is stopped, and a switch is set so as not to select any one of the antennas, thereby totally reflecting the transmit signal; in this condition, the timing is controlled so that the average value of the output level of a mixer becomes a minimum. When adjusting the antenna selection timing, modulation of the transmit signal is stopped, and a reflective object is placed in close proximity to the antenna; in this condition, the timing is adjusted so that the average value of the output level of the mixer becomes a maximum.

Abstract: A method of reducing power to an electron emitting cathode comprises the steps of sensing a weather condition; calculating a condition number based upon the weather condition; comparing the condition number to a threshold; and reducing the power to the electron emitting cathode when the condition number is greater than the threshold. The apparatus and method may be implemented upon a system having a high voltage power source, an RF tube, a control processor, and a signal processor.

Abstract: An illumination source of predominantly non-directional and incoherent millimeter-wave radiation for illuminating an area for passive millimeter-wave imaging comprises a container with at least a partly reflective internal surface and a plurality of exit apertures and a primary source of millimeter-wave radiation for emitting millimeter-wave radiation into the container. The primary source and the container are arranged so that a proportion of the millimeter-wave radiation emitted by the source undergoes reflection within the container before being emitted through the apertures, such that the different paths lengths are at least equal to the coherence length of the radiation. This is facilitated if the bandwidth of the radiation is preferably at least 1 GHz. The container may be a box in which a waveguide is used to couple radiation from the primary source into the box. Alternatively, the container may be formed from a mesh and the plurality of holes is provided by the holes in the mesh.

Abstract: A radar level gauge using electromagnetic waves for determining a process variable of a product in a tank, comprising timing circuitry adapted to provide timing control of a transceiver, and a communication interface arranged to receive power in an intrinsically safe manner and to connect the radar level gauge externally thereof. The RLG further comprises an isolation interface arranged to galvanically isolate the transceiver from the timing circuitry and the communication interface, the isolation interface being arranged to transfer power and timing control from the timing circuitry and the communication interface to the transceiver circuitry. According to this design, the galvanic isolation splits the radar level gauge system internally into two circuits, with no galvanic connection there between. An advantage is that this design eliminates any potential ground loops between the transceiver and the communication interface.

Abstract: A method and a device for adaptively controlling power in a radar device having a radar transmitter and a radar receiver are provided, in particular for applications in vehicles. The radar signals are emitted, and radar signals reflected off of target objects are received and checked for irregularities. The transmitting power of the radar transmitter is reduced when irregularities occur which are attributable to interference caused by neighboring radar transmitters.

Abstract: A method of reducing power to an electron emitting cathode comprises the steps of sensing a weather condition; calculating a condition number based upon the weather condition; comparing the condition number to a threshold; and reducing the power to the electron emitting cathode when the condition number is greater than the threshold. The apparatus and method may be implemented upon a system having a high voltage power source, an RF tube, a control processor, and a signal processor.

Abstract: In a high-frequency circuit having a substrate having a high-frequency transmission line and an dielectric resonator formed on said substrate so that said dielectric resonator and said high-frequency transmission line may be coupled electro-magnetically to each other, a hole part or a cavity part is formed at a part of said substrate and a dielectric resonator is embedded in said hole part or said cavity part. In the same object, a high-frequency circuit having a dielectric resonator is produced by the step for forming a high-frequency transmission line on a substrate, the step for forming a hole part or a cavity part on a part of the substrate, and the step for mounting a dielectric resonator in the hole par formed on the surface of the substrate.

Abstract: Provided is a millimeter-wave transmitting/receiving apparatus of pulse-modulation type in which pulse-modulated millimeter-wave signals for transmission are prevented from being outputted to a reception system due to inner reflection or other causes. Included are: an NRD guide (basic structure) formed of a dielectric line sandwiched between parallel plate conductors; a millimeter-wave signal oscillator; a pulse modulator; a circulator; a transmitting/receiving antenna; and a mixer. At the output end of the mixer is disposed a switching device which interrupts intermediate-frequency signals in an opened state, and, when a millimeter-wave signal for transmission from the pulse modulator enters a non-output state and the condition is stabilized, changes into a closed state to pass intermediate-frequency signals.

Abstract: A power supply apparatus controls the gate and drain power supplies at the rise time so that an output voltage of the gate power rises earlier than that of the drain power supply. Another power supply control apparatus controls the gate and drain power supplies at the fall time so that an output voltage of the gate power supply fails later than that of the drain power supply. Another power supply control apparatus turns off the drain supply of the FET among power supplies when it is detected by a voltage monitor whenever either of output voltages or the power supplies are not within said specified range.

Abstract: A method for transmitting a signal waveform from a transmitter within an adaptive broadcast radar system. In one embodiment, wherein the transmitter comprises at least one sub-aperture, the method includes: generating the signal waveform at the at least one sub-aperture; coding the signal waveform at the at least one sub-aperture, wherein the signal waveform is coded with transmitter data; phase shifting the signal waveform at the at least one sub-aperture; and, transmitting the coded signal waveform from an array element coupled to the sub-aperture according to the phase shifting.

Abstract: A radar apparatus including units for transmitting and receiving an electric wave to detect a target, a unit for detecting wave interference caused by surroundings, a unit for controlling the modulation state of the transmitted wave, a communication unit for acquiring modulation state information being used by the other radar apparatuses, and a unit for selecting such a modulation state as to avoid interference with the modulation state information when the wave interference detecting unit detects the wave interference.

Abstract: A method and apparatus for conducting an overhead crane runway system survey uses a survey apparatus that is alternately pushed or pulled by an overhead crane. The survey apparatus, having a wheeled carriage, includes survey sighting targets, e.g., prisms, that are visible to survey personnel on the ground. XYZ data is there collected and a rail alignment profile, a rail elevation profile, a rail span profile, and/or a crane skew profile may be generated. The data and profiles generated may reviewed to ascertain whether the overhead rails conform to alignment specifications. Further, crane skew data may be reviewed to determine whether the crane itself may be misaligned.

Abstract: The present invention is a man-portable counter-mortar radar (MCMR) radar system that detects and tracks enemy mortar projectiles in flight and calculates their point of origin (launch point) to enable and direct countermeasures against the mortar and its personnel. In addition, MCMR may also perform air defense surveillance by detecting and tracking aircraft, helicopters, and ground vehicles. MCMR is a man-portable radar system that can be disassembled for transport, then quickly assembled in the field, and provides 360-degree coverage against an enemy mortar attack.

Abstract: A radar system transmits an environment-sensing pulse and processing circuitry time-reverses an order of radar return samples and generates a convolution matrix from the radar return samples resulting from a transmission of the environment-sensing pulse. The processing circuitry may also generate a plurality of return energy-ranked vectors from a decomposition of the convolution matrix. The processing circuitry may select one of the return energy-ranked vectors for generation of a clutter-orthogonal transmit waveform. In some embodiments, the processing circuitry may select a clutter-orthogonal vector from the plurality of return energy-ranked vectors and may quantize the clutter-orthogonal vector for application to the phase modulator for generation of the clutter-orthogonal transmit waveform. The radar system may perform multiple correlations on sampled radar returns from the clutter orthogonal transmit waveform using a family of pseudo-orthogonal waveforms to detect a slow-moving target.

Abstract: Apparatus and methods for adjusting or “hopping” the center frequency or the pulse repetition frequency of a radar system improve the co-locatability of multiple radars commonly located in a region. In a Time Domain Downconversion (TDDC) or Ultra-Wideband (UWB) radar system having a display update period between range sweeps, the preferred device comprises a frequency variable oscillator for adjusting the radar's internal timing reference frequency during a plurality of the display update periods. Radar frequency hopping methods and apparatus may result in improvements in interference immunity compared to other interference reduction techniques and may achieve cost reduction. In frequency hopping radar, if an actual target is present, the receiver waveform will repeat at the newly adjusted center frequency. Confirmation of a target is realized as an ongoing reflection and not interference.

Abstract: A method of radar measurement by transmitting and receiving radar signals with at least two spatially separated radar systems. The method further includes exchanging reference radar signals between the at least two radar systems to determine measurement-relevant parameters. Moreover, a determination of at least one of a relative phase relationship of the reference radar signals of the radar systems and a relative time position of time references of the radar systems is based on reference radar signals received. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: An apparatus for estimating direction of arrival of signal is provided that has excellent performance in terms of angular resolution and the number of signals that can be identified. In an array sensor comprising a plurality of sensor elements, the two outermost sensor elements are alternately selected by a switch for use as a transmitting sensor, and the other sensor elements are selected in time division fashion as receiving sensors. With this arrangement, the effective aperture is increased to about twice the physical aperture, to improve angular resolution in a direction-of-arrival estimator.

Abstract: An imaging apparatus has transmitter illuminating a selected surface with a radar beam footprint, and processor for profiling/processing the radar returns so as to derive attitude information in real time about a number of predefined axes associated with the radar which depends upon the relative dispositions of the radar, the selected surface and upon the radar beam footprint characteristics. A plurality of transmit beams image the surface and the processing arrangement has the capability of determining roll, pitch and/or yaw pointing data associated with the radar, such pointing data being determined by derivation of the attitude information and by selective input of terrain elevation data so as to take account of variations in the radar viewing geometry with terrain elevation. This provides a low cost advantage over known radar designs, and retains utility for many applications, for example spaceborne and airborne applications.

Abstract: To provide a radar system for controlling a gate power supply and drain power supply of a MMIC (microwave monolithic IC), protecting the MMIC at the time of start and shut-off, and simultaneously avoiding an occurrence of a failure in the MMIC due to a residual charge and an abnormal supply potential at the time of shut-off. A power supply control means controls the gate and drain power supplies at the rise time so that an output voltage of the gate power supply rises earlier than that of the drain power supply. Another power supply control means controls the gate and drain power supplies at the fall time so that an output voltage of the gate power supply falls later than that of the drain power supply. Another power supply control means turns off the drain power supply of the FET among power supplies when it is detected by a voltage monitoring means that even either of output voltages of the power supplies is not within said specified range.

Abstract: A radar apparatus for a vehicle radiates laser beams and integrates a plurality of received signals corresponding to the same plurality of successively radiated laser beams. Thus, the sensitivity to detect a beam-reflecting body is improved. Further, a sampling start timing of the received signals is delayed as a delay time relative to a radiation timing of the laser beam corresponding to the received signal. By changing the delay time, beam-reflecting bodies throughout all detection distances can be detected even when the number of sampling points is made smaller than the number of sampling points required to cover all the detection distances in order to reduce the integration processing load.

Abstract: A system for transmitting into a shared medium includes a processor, a transmitter, and a receiver. The processor is coupled to the transmitter for transmitting in a manner, at a time, and at a power level as directed by the processor. The processor determines from cooperation with the receiver the number of transmitters expected to be sharing the medium at a future time when transmitting is desired; prescribes a total power for a plurality of transmissions; and prescribes a maximum power for individual transmissions of various types.

Abstract: A digital synthesizer includes a digital radio frequency memory (DRFM) for storing phase values and corresponding digital signals. The digital synthesizer includes a digital processing circuit receiving input from the DRFM, the circuit including tapped delay lines and a summer summing the output of the tapped delay lines. The digital synthesizer includes a signal modulator independently synthesizing within each tapped delay line a frequency modulated and gain scaled signal, wherein input to the tapped delay lines are phase values from the DRFM.

Abstract: A unique hardware architecture that combines short pulse, stepped frequency and centerline processing. The inventive architecture implements a radar system having a transmitter for transmitting short pulses, each pulse being stepped in frequency and a receiver receiving the pulses and providing an output signal in response thereto. In the illustrative embodiment, the transmitter includes a frequency source, an RF switch coupled to the source and a controller for controlling the RF switch. The receiver includes a signal processor implemented with a center line roughing filter. The signal processor has multiple channels each of which has a range gate and a digital filter. The digital filter includes a Fast Fourier Transform adapted to output a range Doppler matrix.

Abstract: In a radio wave radar system using a two-frequency CW modulation method, it is possible to detect a distance between a host vehicle and a forward vehicle and to realize a stable ACC following travel, even in a condition in which the relative speed is 0. By combining the two-frequency CW modulation method with the frequency pulse CW modulation method, that is, by using combination with the two-frequency CW method when the relative speed occurs and the frequency pulse CW method when the relative speed is close to 0, even if the relative speed is 0, the IF signal obtained from the reflected wave from the forward vehicle can be generated to detect the existence of the ACC target vehicle, so that it is possible to realize a stable ACC following travel.

Abstract: In a radar apparatus for automobiles for transmitting a radio wave, receiving a radio wave reflected from an object and measuring a rate of the object, a digital signal processor has at least two operation modes, a normal operation mode and a low energy consumption mode, and has a function of switching between the operation modes of the digital signal processor in accordance with a signal supplied from a counter (judgement unit) for judging whether a received signal satisfies predetermined conditions. The radar apparatus can reduce consumption power when necessary.

Abstract: A radio frequency device has an antenna for capturing an incoming signal for processing by the device or for radiating an outgoing signal from the device and a signal processor having one or more synchronous oscillators responsive to an input signal for providing an amplified output signal without using much power. An application is a radio frequency (RF) transponder (tag) for receiving an RF signal from an interrogator includes a tag antenna for receiving the RF signal from the interrogator and a receiver section connected to the tag antenna wherein the receiver consumes a significantly lower amount of power than conventional receiver technologies by using one or more synchronous oscillators.

Abstract: A method and apparatus comprising four co-planar metallic plates, two for transmission and two for reception, in which each pair of co-planer metallic plates of overall length L are disposed either in direct contact with the earth or are elevated a distance Z above the earth to form a capacitor comprising the metallic plates and the earth if Z=0 or if Z>0, the metallic plates, the air space and the earth. A short voltage or current pulse is applied to this capacitor via a transformer in which the magnetic flux current is adjusted to provide a pulse of the desired frequency composition in the air-earth propagation medium. This results in a frequency controlled pulse of electromagnetic radiation into the targeted subterranean geology at frequencies <500 KHZ.

Abstract: A radar includes a transmission signal processing system, a reception signal processing system, an auxiliary signal processing system, a transmission-signal input unit, and a search determination unit. The transmission signal processing system transmits a transmission signal. The reception signal processing system receives and processes a reflected wave at a target. The auxiliary signal processing system is separate from the reception signal processing system and has the same configuration as at least a part of the reception signal processing system having a low operation speed. The transmission-signal input unit inputs a signal generated in the transmission signal processing system to the auxiliary signal processing system directly. The search determination unit makes a determination on the search for the target on the basis of processing results of the received reflected wave by the reception signal processing system and the directly input signal by the auxiliary signal processing system.

Abstract: A radar gauge adapted to sense fluid level in a tank and including a radar gauge circuit in which radar transmission and level sampling are controlled by a transmit frequency and a sample frequency respectively. A first frequency separation between first and second frequencies is controlled by a control input. The first and second frequencies can be divided to generate the transmit and sample frequencies, separated by a second frequency separation. At least one frequency difference is evaluated and the evaluation used to generate the control input, stabilizing the first frequency difference, and to correct the gauge output.