Abstract: A detection method includes determining a first frequency point of N frequency points, transmitting a radio signal in a first frequency band in N frequency bands. One of the N frequency bands partially overlaps at least one frequency band in other N?1 frequency bands, and an absolute value of a difference between lowest frequencies of any two frequency bands of the N frequency bands is not less than a first threshold (F), or the N frequency bands have at least one second frequency band that partially overlaps the first frequency band, and an absolute value of a difference between a lowest frequency of each second frequency band and a lowest frequency of the first frequency band is not less than F.

Abstract: Apparatus and methods for front-end systems with directional couplers and a shared back switch are provided. In certain configurations, a method includes transmitting a first transmit signal from a first transmit port to an antenna port, generating a first coupled signal in response to the first transmit signal using a first directional coupler, providing the first coupled signal to a receive port by way of a first loopback selection switch and a shared back switch, transmitting a second transmit signal from a second transmit port to the antenna port, generating a second coupled signal in response to the second transmit signal using a second directional coupler, and providing the second coupled signal to the receive port by way of a second loopback selection switch and the shared back switch.

Abstract: A continuous wave radar system comprises a substrate, a transmitter disposed on the substrate, a receiver disposed on the substrate, and an isolating device comprising a plurality of metal plates parallelly disposed on the substrate between the transmitter and the receiver for isolating leakage signal transmitted from the transmitter to the receiver. The metal plates are grounded with the transmitter and the receiver via electrical connection between the metal plates and the substrate. The metal plates are so arranged that an eddy current induced in each of the metal plates is directed away by grounding when the leakage signal passes through the metal plates.

Abstract: An analog self-interference cancellation technique for In-Band Full-Duplex (IBFD) systems generates an inherent secondary self-interference (SI) signal of a circulator and uses that signal to cancel a primary SI signal leaked from a transmitter port within a communication device. The communication device manipulates the phase and angle of this secondary SI, using an adjustable Impedance Mismatch Terminal (IMT) circuit. The result is an efficient SI cancellation technique in the analog domain, which uses the circulator inherent SI signals.

Abstract: The present disclosure provides a system for processing radar data. The system may comprise a frequency generator configured to generate a reference frequency signal; a timing module configured to generate one or more timing signals; and a plurality of radar modules in communication with the frequency generator and timing module. The radar modules may be configured to: (i) receive the reference frequency signal and the one or more timing signals, (ii) transmit a first set of radar signals based in part on the reference frequency signal and the one or more timing signals, and (iii) receive a second set of radar signals reflected from a surrounding environment. The system may comprise a processor configured to process radar signals received by the plurality of radar modules, by coherently combining radar signals using phase and timestamp information.

Abstract: For the process for determining a distance, there is provided a succession of coded signals at high frequency transmitted between a base station and a wearable object. A preparation of a response signal is conducted in the wearable object on reception of the first synchronisation signal after activation of the wearable object. A transmission of successive coded signals at high frequency from the wearable object is conducted for the station, of which the last response signal is scrambled by a modulation of data on the last signal received at a high transfer rate from the station. An analysis is conducted in a processing unit of the base station after reception of the signals from the wearable object to accurately determine the distance separating the base station from the recognised wearable object.

Abstract: A method for concurrent transmission of different signal types by a radar system includes: receiving a waveform request for transmitting a first signal type and a second signal type; determining whether the first signal or the second signal is optimized; when the first signal is optimized: transmitting the first and the second signal simultaneously in separate bands; and when the second signal is optimized: determining a time gap between transmission of the second signal, and adjusting pulse repetition interval (PRI) or pulse width of the first signal to fit in the time gap, transmitting the second signal, and transmitting the first signal in the time gap between the transmission of the second signal.

Abstract: In a simultaneous transmit and receive (STAR) communication system, an RF signal splitter couples an antenna to an RF transmitter and to an RF receiver, without using a circulator. An adaptive cancellation RF waveform generator generates an adaptive cancellation RF signal to cancel cross-talk from the RF transmitter to the RF receiver. Training signals are used to characterize signal paths within the STAR system and calculate filter coefficients for generating the adaptive cancellation signal.

Abstract: In some examples, an FMCW radar array includes a housing, a transmit array comprising a plurality of transmit antenna elements configured to output an FMCW transmit beam, a receive array comprising a plurality of receive antenna elements, and a slotted choke disposed between the transmit array and the receive array. The transmit array and the receive array may be mechanically coupled to the housing. In some examples, the slotted choke comprises a plurality of slots having dimensions selected to provide cancellation of electromagnetic radiation from the frequency modulated continuous wave transmit beam to reduce a magnitude of radiation from the transmit array to which the receive array is indirectly exposed.

Abstract: An ultrasonic transmission and reception device is described. This includes a transmission circuit for generating a transmission signal at its transmission outputs and, an ultrasonic transducer, which is suited for converting electrical signals into sound signals and sound signals into electrical signals, a transformer, the primary side of which is connected to the transmission outputs and of the transmission circuit and the secondary side of which is connected to the ultrasonic transducer, and a reception circuit for processing a received signal present at its reception input.

Abstract: A radar apparatus for a vehicle includes a radar unit provided at an inner side of a radiator grill for a vehicle, a multi-layer transmission cover which is fitted into the radar unit and on a front surface of which a plurality of transmission layers through which a radar beam radiated through the radar unit transmits are formed, and a mounting portion in which a connection body formed by connecting the multi-layer transmission cover to the radar unit is connected to a vehicle body.

Abstract: A simultaneous transmit and receive (STAR) system includes a first bidirectional signal port coupled to an antenna, a second port coupled to a transmit signal path, and a third port coupled to receive signal path. A first switch is electrically connected between the first port and the second port, where a transmit signal propagating in the transmit signal path passes through the first switch when closed and then through the first bidirectional signal port to the antenna where the transmit signal is radiated by the antenna. A second switch is connected between the first port and the third port, where a receive signal is received by the antenna and passes through the bidirectional signal port and then through the second switch when closed to the receive signal path. A controller is electrically connected to a control input of each of the first and second switches.

Abstract: There is provided a radar receiver that effectively prevents local oscillator signals from leaking out from an antenna. A receiver 21 includes a local oscillator 5, a mixer 6, a buffer amplifier 11, and a mode switcher 16. The local oscillator 5 outputs a local oscillation signal LO. The mixer 6 mixes a high-frequency signal RF received by a radar antenna 2 with the local oscillation signal LO. The buffer amplifier 11 is disposed between the local oscillator 5 and the mixer 6. The mode switcher 16 switches at least between a standby mode in which power is supplied to the local oscillator 5 and no power is supplied to the buffer amplifier 11 and a reception mode in which power is supplied to both the local oscillator 5 and the buffer amplifier 11.

Abstract: A radar system includes a receiver that is capable of attenuating transmitter feedthrough in a receive signal. In some embodiments, a fixed frequency notch filter is used to attenuate feedthrough at an intermediate frequency (IF). In other embodiments, an electronically tunable notch filter is used. Phase compensation may be provided to correct for a phase shift of the notch filter.

Abstract: One embodiment is directed towards a FMCW radar having a single antenna. The radar includes a transmit path having a voltage controlled oscillator controlled by a phase-locked loop, and the phase-locked loop includes a fractional-n synthesizer configured to implement a FMCW ramp waveform that ramps from a starting frequency to an ending frequency and upon reaching the ending frequency returns to the starting frequency to ramp again. The radar also includes a delay path coupled between a coupler on the transmit path and a mixer in a receive path. The delay path is configured to delay a local oscillator reference signal from the transmit path such that the propagation time of the local oscillator reference signal from the coupler to the mixer through the delay path is between the propagation time of signal reflected off the antenna and the propagation time of a leakage signal through a circulator.

Abstract: A spiral resonator is analyzed by modeling a set of loops of the spiral resonator with a model of a circuit including a set of units, wherein each unit includes a resistor and an inductor to model one loop of the spiral resonator. Values of the resistor and the inductor of each unit are based on properties of a corresponding loop. Electrical connection of the loops is modeled by electrically connecting the units in a corresponding order of the loops. A capacitive coupling in the spiral resonator is modeled by connecting adjacent units with at least one capacitor having a value based on the capacitive coupling between two corresponding adjacent loops. An inductive coupling in the spiral resonator is modeled based on inductive coupling between pairs of loops. The operation of the spiral resonator is simulated with the model of the circuit.

Abstract: The invention relates to a measuring device, especially for a machine tool and/or a manual measuring device, comprising a measuring unit (12a-d) that is adapted to measure and an external signal recognition unit (14a-d). The invention is characterized in that the external signal recognition unit (14a-d) is adapted to recognize an external signal during and/or prior to a measurement of the measuring unit (12a-d).

Abstract: A method of fabricating an array of radiating elements includes on one layer or surface of a dielectric substrate, forming a first leg of a first resonator loop, on another layer or surface of the dielectric substrate forming a second leg of the first resonator loop between adjacent radiating elements, forming a via through the dielectric substrate, and metallizing the via forming a third leg of the first resonator loop interconnecting the first and second legs.

Abstract: To provide a smaller radar system having a simple structure with as small number of component parts as possible at a lower cost as compared to conventional ones. A radar system 1 including a 3 dB coupler 5 having four terminals, and a pulse generator 8. A first terminal 51 of the 3 dB coupler 5 is supplied with an output signal from a high frequency oscillator 2 while a second terminal 52 of the 3 dB coupler 5 is connected to a transmitting and receiving antenna 4. Third and fourth terminals 53 and 54 of the 3 dB coupler 5 are connected to two-state devices 6, 7, respectively, which are in impedance mismatched only for a predetermined period of time to totally reflect the signal from the 3 dB coupler 5 and are in impedance matched during the time period other than the predetermined time to direct a signal from the 3 dB coupler 5 to a subsequent electronic circuit.

Abstract: A vanadium dioxide front-end advanced shutter device. The electronic shutter device is designed to protect receiver front-ends and other sensitive circuits from HPM pulse events such as HPM weapons, directed energy weapons, or EMPs. The shutter incorporates a transition material such as thin-film vanadium oxide (VOX) materials that exhibit a dramatic change in resistivity as their temperature is varied over a narrow range near a known critical temperature. A high-energy pulse causes ohmic heating in the shutter device, resulting in a state change in the VOX material when the critical temperature is exceeded. During the state change the VOX material transitions from an insulating state (high resistance) to a reflective state (low resistance). In the insulating state, the shutter device transmits the majority of the signal. In the reflective state, most of the signal is reflected and prevented from passing into electronics on the output side of the shutter device.

Abstract: A method for asynchronous transmission of communication data between periodically blanked terminals separated by an unknown distance is disclosed. A bursted signal is transmitted from a first terminal with a burst time tB and a burst cycle period T. The bursted signal is received at a second terminal. A bursted response signal is transmitted from the second terminal to the first terminal. The bursted response signal has a burst cycle period of T/2 and includes a pair of response bursts, with each burst in the pair having a burst time tA?T/2?tB. Each burst in the pair of response bursts carries an identical data payload. At least one of the response bursts is received at the first terminal.

Abstract: Methods and systems for reducing a leakage component of a received-signal are disclosed. A transmit antenna of a radar system transmits a transmit-signal including a transmit component. A receive antenna of the radar system receives a received-signal including a leakage component and a target component. The received-signal corresponds to the transmit-signal. An overlap determination is made to determine whether the target component overlaps the leakage component and/or is received during a time when the leakage component is expected to be received. If overlap exists, a reduction leakage component (e.g., a previously determined reduction leakage component) is subtracted from the received-signal so as to produce a modified received-signal, the modified received-signal including the target component and substantially excluding the leakage component.

Abstract: A multilayer metamaterial isolator and method of fabricating the same. A first layer or surface of a multilayer dielectric substrate includes a first leg of a first resonator loop. A second layer or surface of the multilayer dielectric substrate includes a second leg of the first resonator loop. A third leg of the first resonator loop extends through the multilayer dielectric substrate interconnecting the first and second legs of the first resonator loop.

Abstract: An enhanced duplexer (1) which includes a combination of high dynamic range (HDR) amplifiers (11, 17) and a naovel signal cancellation circuit topology (15). Return signals from the circulator (3) are fed into the first HDR amplifier (11). A portion of the transmit signal is sampled with a directional coupler (7) and amplified with a second HDR amplifier (17) and then combined with the output of the first HDR amplifier (11) using a second directional coupler (13). The gain and phase of the second io amplifier (17) are adjusted so the leakage signals are canceled (19, 21) to enable a radar system to simultaneously transmit and receive signals to and from an antenna with increased sensitivity of operation.

Abstract: A method, computer program product, apparatus and system are provided. In one exemplary embodiment, a method includes: receiving at a second unit periodic energy bursts transmitted by a first unit; blanking a transmitter of the second unit in accordance with the received periodic energy bursts such that the transmitter is unable to transmit when the second unit is receiving a periodic energy burst; and transmitting a plurality of instances of a same data from the second unit to the first unit.

Abstract: A radar level gauge (RLG) using electromagnetic waves for determining a process variable of a product in a tank is provided which includes 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.

Abstract: The present invention, in order to enable intermittent output of an oscillation signal without essentially producing a leak in response to a pulse signal indicating a transmission timing of a radar wave, employs a configuration in which an operation of an oscillating unit (21) itself of a radar oscillator is alternately changed between an oscillating state and an oscillation stop state by a switch (30), not a configuration in which an output passage of an oscillation signal is switched to be opened and closed as in a conventional radar oscillator.

Abstract: An enhanced duplexer (1) which includes a combination of high dynamic range (HDR) amplifiers (11, 17) and a naovel signal cancellation circuit topology (15). Return signals from the circulator (3) are fed into the first HDR amplifier (11). A portion of the transmit signal is sampled with a directional coupler (7) and amplified with a second HDR amplifier (17) and then combined with the output of the first HDR amplifier (11) using a second directional coupler (13). The gain and phase of the second io amplifier (17) are adjusted so the leakage signals are canceled (19, 21) to enable a radar system to simultaneously transmit and receive signals to and from an antenna with increased sensitivity of operation.

Abstract: An active antenna is provided that includes an antenna element for transmitting RF transmit signals at a predetermined effective radiated power (ERP). An antenna module is configured to be mounted to an aircraft, with the antenna element being mounted to the antenna module. A connector module is provided at the antenna module and is configured to be coupled to a communications link and receive electrical transmit signals from the communications link. A transmit path is provided within the antenna module and extends between the antenna element and the connector module. A power amplifier is provided on the antenna module along the transmit path. The power amplifier increases a power level of the electrical transmit signals, received from the communications link, by a predetermined amount sufficient to drive the antenna element to transmit the RF transmit signals at the predetermined ERP.

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 multi-element antenna with sufficiently small return loss and mutual coupling signals to allow the simultaneous transmission of powerful radar signals and the reception of faint target return signals. The microstrip patch antenna has radio frequency absorbing material place between neighboring antenna elements to reduce the mutual coupling leakage signals.

Abstract: A radar detector includes features to reduce emissions such as those typically generated by the detector's local oscillator. Two low noise amplifiers (LNA's), operating in X band and a combined K/Ka band, respectively amplify X and K/Ka band signals from separate antennae, and deliver those signals over separate, elongated and narrow signal paths to X and K/Ka mixers, where those signals are mixed with local oscillator (LO) signals to produce IF for detection. The elongated, narrow signal paths from the antennae to the mixers reduce LO emissions, and those emissions are further reduced by incorporating radar absorbers between the circuit board and detector case along the antenna-mixer path, including radar absorptive paint on the circuit board itself along this path, and sealing the case with a conductive sealing gasket.

Abstract: A radar includes a transmitter circuit, a receiver circuit, an antenna and a circulator. The receiver circuit includes a low-noise amplifier which amplifies a received signal fed from the antenna through the circulator. A local oscillator provided in the receiver circuit generates a local oscillator signal of which frequency is approximately half the frequency of the received signal, and the local oscillator signal is amplified by a buffer amplifier. An even harmonic mixer including an anti-parallel diode pair also provided in the receiver circuit as a frequency converter mixes the received signal output from the low-noise amplifier with the local oscillator signal output from the buffer amplifier to generate and output an intermediate frequency signal.

Abstract: A radar system (500) radiates a radar transmit signal, has a radar signal receiver (503) and a canceller (505) for canceling leakage of the transmit signal into the radar signal receiver (503). The canceller (505) comprises a digital waveform generator (528) for generating a first digital signal converted to an analog waveform. The analog waveform is amplified after a fixed delay (534) to generate a first cancellation signal input into a circulator (504). The circulator combines the first cancellation signal with the leakage to generate a first corrected signal. A summer (507) combines the first corrected signal from the circulator with a second cancellation signal to generate a second corrected signal. The second cancellation signal is generated by a digital cancellation filter (526). The digital cancellation filter (526) has as an input the first digital signal from the digital waveform generator (528).

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 vehicle-installed radar sensor system includes a transmission section, a reception section, and a shield member. The transmission section is disposed in a closed space formed between a permeable member provided in a vehicle and a vehicle body, and transmits a radar wave to outside of the vehicle through the permeable member. The reception section is disposed in the closed space at a distance from the transmission section, and receives a reflected wave by a target through the permeable member. The shield member is disposed in at least one of the transmission section and the reception section, and suppresses at least one of occurrence of a reflected wave by the permeable member and reception of the reflected wave by the permeable member.

Abstract: A radar altimeter for an air vehicle is described. The radar altimeter includes a transmit antenna configured to transmit radar signals toward the ground, a receive antenna configured to receive radar signals reflected from the ground, the receive antenna also receiving signals propagated along a leakage path from the transmit antenna, and a receiver configured to receive signals from the receive antenna. The radar altimeter also includes at least one altitude processing channel configured to receive signals from the receiver to determine an altitude, and an automatic sensitivity-range-control (SRC) channel configured to receive signals from the receiver. The SRC channel is configured to determine an amplitude of the received leakage path signals when an altitude of the radar altimeter is sufficient to separate received signals reflected from the ground from signals received from the leakage path.

Abstract: A millimeter wave radar for the purpose of automatic operation or collision prevention of a vehicle which solves the problem that a side lobe of a transmitted electromagnetic wave is reflected by surrounding bodies and the reflected wave is received, with the result that unnecessary bodies may also be detected. A layer higher in dielectric loss than a radome or a magnetic loss layer and a conductor layer in a mesh form are embedded in a part of the inside surface of the radome, whereby it is possible to provide a millimeter wave radar which is light in weight, excellent in weathering performance, inexpensive, and excellent in detection performance.

Abstract: A vehicle-installed radar sensor system includes a transmission section, a reception section, and a shield member. The transmission section is disposed in a closed space formed between a permeable member provided in a vehicle and a vehicle body, and transmits a radar wave to outside of the vehicle through the permeable member. The reception section is disposed in the closed space at a distance from the transmission section, and receives a reflected wave by a target through the permeable member. The shield member is disposed in at least one of the transmission section and the reception section, and suppresses at least one of occurrence of a reflected wave by the permeable member and reception of the reflected wave by the permeable member.

Abstract: A guided wave radar measurement instrument comprises a probe defining a guided wave radar transmission line. A pulse circuit is connected to the probe for generating a very fast stream of pulses on the transmission line and receiving reflected pulses returned on the transmission line. The reflected pulses represent a characteristic of a material being measured. An equivalent time sampling circuit is connected to the pulse circuit operable to sample reflected pulses to build a time multiplied picture of the reflected pulses and comprises a ramp generator circuit generating a saw tooth ramp signal used to selectively delay sampling reflected pulses to build the time multiplied picture. In one aspect of the instrument, the saw tooth ramp signal has a controlled ramp start for each cycle and retrace at an end of the cycle.

Abstract: A process instrument comprises a housing, a terminal in the housing for connection to a two-wire process loop and an active element for sensing a characteristic of a process. A control circuit is disposed between the terminal and the active element for measuring the sensed characteristic and controlling the two-wire process loop responsive to the sensed characteristic. A split intrinsic safety barrier comprises current limiters electrically connected between the terminal and the control circuit and a diode safety barrier electrically connected between the control circuit and the active element.

Abstract: A process instrument comprises a housing, a terminal in the housing for connection to a two-wire process loop and an active element for sensing a characteristic of a process. A control circuit is disposed between the terminal and the active element for measuring the sensed characteristic and controlling the two-wire process loop responsive to the sensed characteristic. A split intrinsic safety barrier comprises current limiters electrically connected between the terminal and the control circuit and a diode safety barrier electrically connected between the control circuit and the active element.

Abstract: In a single-antenna time division control type FM-CW radar, an amplifier is provided in each signal path in a transmitting system and a receiving system, and the amplifier provided in the transmitting system and the amplifier provided in the receiving system are operated alternately in synchronism with transmit and receive timings, to perform switching between transmission and reception. The operation of the amplifiers is controlled by controlling the gain of each of the amplifiers. This configuration provides enhanced isolation between the transmitting and receiving systems, and prevents transmitting power from leaking into the receiving system through a transmit-receive switching section.

Abstract: A gas plasma type receiver protector for a radar system includes a priming device in the form of a miniature high intensity blue light emitting diode (LED) ranging in wavelength from 470 nm to 490 nm, an ultra-violet LED, miniature lamp or laser diode ranging in wavelength from 260 nm to 470 nm.

Abstract: A continuous wave radar system includes a transmitter circuit for generating radar transmitting signals, a transmit/receive antenna, coupled to the transmitter circuit by way of a circulator, and a receiver circuit, which is coupled to the transmit/receive antenna by way of the circulator and which is intended to process radar echo signals of a target object. The radar echo signals are received at the transmit/receive antenna, wherein the circulator serves to pass the transmitting signals, generated by the transmitter circuit, to the transmit/receive antenna and to divert the target object's echo signals, which are received by the transmit/receive antenna, to the input of the receiver circuit.

Abstract: The invention relates to a filling level measuring device based on the principle of transit time measurement. An inventive filling level measuring device comprises an electronic unit (4) including a transmitting (9) and receiving means (10) for electromagnetic waves having a frequency of below 3 GHz, a process coupling means (5) connected to the electronic unit (4), which guides the transmitted signals onto the measurement distance, and guides back reflected signals to the electronic unit (4), and a high-frequency transformer (15, 16, 17, 18), to which the transmitting (9) and receiving means (10) and the process coupling means (5) are connected.

Abstract: A video amplifier for a radar receiver includes a temperature compensating attenuator. The attenuator includes a temperature sensitive device, such as a thermistor, arranged in a voltage divider network and is coupled in cascade between two filter stages. Each of the filter stages has a bandpass characteristic in order to filter low-frequency leakage signals and provide sensitivity control based on frequency and thus range, while also filtering high frequency signals to reduce aliasing.

Abstract: A radio frequency module includes a multi-chip substrate divided into separate substrates. An antenna block, a duplexer block, a transmitter block, a receiver block, and an oscillator block are formed on the separate substrates. Connection resonators, which are connected to transmission lines, are formed at edges of the separate substrates. The connection resonators on adjacent ones of the separate substrates are arranged close to each other such that the two adjacent resonators are electromagnetically coupled to each other. Thus, the transmission lines on the separate substrates are interconnected, and a signal can be propagated among the blocks.

Abstract: First-arriving-pulse detector (FAP) circuitry includes a correlator circuitry and a threshold circuitry. The correlator circuitry correlates a received signal with a template signal to provide an output signal. The threshold circuitry provides a first-arriving-pulse signal depending on the relative values of the output signal of the correlator circuitry and a threshold signal.

Abstract: In a single-antenna time division control type FM-CW radar, an amplifier is provided in each signal path in a transmitting system and a receiving system, and the amplifier provided in the transmitting system and the amplifier provided in the receiving system are operated alternately in synchronism with transmit and receive timings, to perform switching between transmission and reception. The operation of the amplifiers is controlled by controlling the gain of each of the amplifiers. This configuration provides enhanced isolation between the transmitting and receiving systems, and prevents transmitting power from leaking into the receiving system through a transmit-receive switching section.