Abstract:
A radar based sensor detection system comprises a microwave source (10) operative to provide a continuous wave signal at an output. A pulse-former (13) is coupled to the output of the source and is operative to provide at an output a variable length pulse that increases the transmitted energy of the radar system according to the range of object detection. A modulator (16) is coupled to the output of the pulse-former for providing a modulated pulse signal. A transmit receive switch (18) coupled to the output of the modulator is selectively operative between a first transmit position and a second receive position. A transmit channel (25, 26, 30) coupled to the transmit receive switch transmits the pulse signal when the switch is operated in the transmit position. A receiving channel coupled to the transmit receive switch receives the modulator signal when the switch is operated in the receive position. First and second voltage multipliers (44, 45) each have a local oscillator input for receiving the modulator signal in the receive position, and each have an input signal port, and an output port. A receiver channel (40, 41, 31) receives a reflected transmitted signal from an output and applies the received signal to the receive signal input ports of the voltage multipliers. An autocorrelator (47, 55) coupled to the output ports of the voltage multipliers correlates the received signal to produce an output signal indicating the detection and position of the object.
Abstract:
The invention is a method and apparatus for determining the locations of a plurality of actual objects based on the output of a plurality of range sensors. A multiplicity of range measurements are obtained from a plurality of sensors, each sensor capable of providing a multiplicity of range measurements. The range measurements from the plurality of sensors are correlated with each other to generate a list of potential objects and to order that list of potential objects from highest to lowest likelihood of being an actual object. The order may be based upon a cumulative error of the individual sensor measurements upon which the potential object is based. The ordered list of potential objects is then pared down to a smaller list of actual objects by assuming that the potential object highest in the ordered list as an actual object, and then removing from the list all other lower-ordered potential objects that are based on any of the range measurements upon which the selected object is based. The process is repeated for the next highest potential object remaining on the list until all potential objects on the list have either been selected as an actual object or removed from the list.
Abstract:
A method and apparatus for producing a modulation scheme usable in conjunction with information transmission and reception via waveforms, such as electromagnetic waves. The modulation scheme is usable for such purposes as resolving range ambiguities and overcoming fading and interference problems via use of offset signals that vary in frequency over time (e.g., chirp signals), which spread the signal over a larger bandwidth. The method includes coding a symbol signal onto a split data stream containing a reference signal (e.g., a chirp), to which a time delay has been applied, then recombining the split streams to produce a composite waveform. The method can also include demodulating a composite received waveform by applying a reference signal to the waveform and then band pass filtering the waveform into discrete symbol data. Apparatus and systems are also provided for performing the method.
Abstract:
A method for transmitting a radar signal comprises the step of transmitting a series of pulses (110), each of the pulses (110) being separated in time by an interpulse period, and each of the pulses (110) in the series being modulated in accordance with a different character of a first code.
Abstract:
A switch matrix (200) including a plurality of microstrip pairs (202-232) arranged to form a grid and switches (234) to couple the microstrip pairs where they cross. Each microstrip pair includes a first microstrip and a second microstrip for passing signals. The signals on the first and second microstrips are such that the electromagnetic forces produced by each one are canceled out by the other. By canceling out the electromagnetic forces, undesirable coupling between microstrips that cross and between microstrips and the substrate are minimized, thereby allowing inexpensive substrates such as silicon to be used.
Abstract:
A system and associated method that combines microwave detection (radiometry) with microwave heating (hyperthermia) for the treatment of cancer with a microwave radiometric detector is operable during a receive mode of operation to establish signal path characteristics and a microwave transmitter is operable during a transmit mode of operation to carry out the hyperthermia treatment. There is provided an antenna array of a plurality antennae (12) disposed over the tumor site (10).These antennae are coupled to separate signal channels. During the receive mode of operation the separate channel signals are combined for coupling to the microwave radiometric detector to enable adjustment of the phase of the separate antenna signals so as to maximize the signal detected at the microwave radiometric detector. Thereafter, during the transmit mode of operation the microwave transmitter couples signals to the signal channels to provide beam focusing of the microwave energy on to the tumor site.
Abstract:
A method and apparatus for cancerous tumor detection employing a plurality of microwave antennae supported in an array conforming substantially in size to the breast that is being screened. In one embodiment of the invention a single array is used and another embodiment for larger breasts a pair of arrays are used. A microwave radiometer is used for detecting temperature readings corresponding respectively to the breast temperature at sites underlying the receiving antennae. Also, in accordance with the invention compression is employed so as to reduce tissue thickness enabling far more rapid reading of antenna sites.
Abstract:
An analog to digital converter (100) is provided that first converts an analog input voltage (Vin+, Vin-) into first (clk+) and second (clk-, clkref) periodic signals having a phase difference there between that is a function of the analog input voltage. The first periodic signal (clk+) is introduced into a forward direction data path through a series of consecutive delay cells so that the first periodic signal propagates through the cells via the first series of delay elements (111 1 -111 2n ) in a first direction. The second periodic signal (clk-, clkref) is introduced into a reverse direction data path through the same series of delay cells so that the second periodic signal propagates through the cells via the second series of delay elements (112 1 -112 2n ) in an opposite direction. Using the second periodic signal (clk-, clkref) to latch the first periodic signal (clk+) in each cell so as to generate an output signal for each cell, said output signals of said cells collectively indicating a unique cell (105 1 -105 2 n ) in which the leading edges of corresponding pulses in the first and second directions met. The outputs of the cells are decoded to generate a digital binary output value.
Abstract:
A method and apparatus is disclosed for generating short electronic pulses using a modified differential trigger that is partly an analogue sinusoidal voltage and partly a selectable, DC voltage. The differential trigger is applied to a differential base band pulse generator (38, 60) having a NAND gate (14) and AND gate (12). The trigger is applied to both NAND inputs and to one AND input. The NAND output is applied the other AND input. Such a circuit is an OFF state for all input states. However, as the input switches state, the NAND gate delay causes the AND gate (12) to be ON briefly, generating a short pulse. The timing of this pulse can be controlled by varying the constant DC voltage. By using fast switching SiGe CML gates, short pulses with a controllable time off-set can be generated that are suitable for use in automotive radar applications, using only sub-GHz clocks.