803 results about "Signal reflection" patented technology

An embodiment of the present invention provides an apparatus, comprising an input port and a dynamic impedance matching network capable of determining a mismatch at the input port and dynamically changing the RF match by using at least one matching element that includes at least one voltage tunable dielectric capacitor. The matching network may be a “Pi”, a “T”, or “ladder” type network and the apparatus may further comprise at least one directional coupler capable of signal collection by sampling a portion of an incident signal, a reflected signal or both. In an embodiment of the present invention, the apparatus may also include a control and power control & logic unit (PC LU) to convert input analog signals into digital signals and sensing VSWR phase and magnitude and processing the digital signals using an algorithm to give it a voltage value and wherein the voltage values may be compared to values coming from the coupler and once compared and matched, the values may be passed to a Hi Voltage Application Specific Integrated Circuit (HV ASIC) to transfer and distribute compensatory voltages to the matching network elements.

An electrical contact system for transmitting information across tool joints while minimizing signal reflections that occur at the tool joints includes a first electrical contact comprising an annular resilient material. An annular conductor is embedded within the annular resilient material and has a surface exposed from the annular resilient material. A second electrical contact is provided that is substantially equal to the first electrical contact. Likewise, the second electrical contact has an annular resilient material and an annular conductor. The two electrical contacts configured to contact one another such that the annular conductors of each come into physical contact. The annular resilient materials of each electrical contact each have dielectric characteristics and dimensions that are adjusted to provide desired impedance to the electrical contacts.

Computerized wireless transmitter / receiver system that automatically uses combinations of various methods, including transmitting data symbols by weighing or modulating a family of time shifted and frequency shifted waveforms bursts, pilot symbol methods, error detection methods, MIMO methods, and other methods, to automatically determine the structure of a data channel, and automatically compensate for signal distortions caused by various structural aspects of the data channel, as well as changes in channel structure. Often the data channel is a two or three dimensional space in which various wireless transmitters, receivers and signal reflectors are moving. The invention's modulation methods detect locations and speeds of various reflectors and other channel impairments. Error detection schemes, variation of modulation methods, and MIMO techniques further detect and compensate for impairments. The invention can automatically optimize its operational parameters, and produce a deterministic non-fading signal in environments in which other methods would likely degrade.

This invention permits the upstream transmission of short packets of information in a cable TV system, and blocking upstream noise at all other times, and does so without interfering with image quality of normal TV viewing. A remotely operable ingress noise blocking filter is placed at the terminating junction between a subscriber's coaxial drop cable and a corresponding feeder tap in a cable TV system. The ingress noise blocking filter contains a high pass filter to pass the normal TV band. This high pass filter is bypassed by a section containing low pass filters and a switch operated when receiving a control signal from a cable modem during those short durations the cable modem is authorized to transmit an upstream signal. Low pass filters isolate the switching elements so that switching transients cannot occur in the downstream TV band. The level of the amplitude of the downstream signal is unaffected whether the switching elements are open or closed. Further, the switching arrangement provides a relatively constant impedance, both when the switching element is on and off to provide a high return loss and avoid signal reflections and maintain signal quality. In a diagnostic mode, the location of each noise source is determined by correlating the energy measured at each a set of frequencies across the band at the headend during those periods when the cable modem is allowed to transmit versus the energy received during those periods when the same cable modem is not authorized to transmit.

Apparatus and methods for the management of radio frequency spectrum within a network such as a CATV network. In one aspect of the invention, an improved signal reflector apparatus adapted for use in the network is disclosed, the reflector circuit being designed to strongly reflect signal frequencies at the lower end of the CATV reverse band, and / or above the higher end of the forward band, while simultaneously allowing the rest of the reverse band and the entire forward band to pass freely through the device. This selective filtering of the spectrum allows control signals generated within a premises or private network to be directed (by reflection) to other devices within that network. A blocking element (e.g., amplifier) may also be used to provide control of the transmission and attenuation profile of the reflector apparatus. The passage of power signals such as DC or low frequency AC is also optionally provided.

Line load compensation and reflection reduction in a signal transmitting circuit is provided using feedback capacitors. The feedback capacitor serially coupled with a resistance generates an RC rise / fall time that is independent of the line load. Additionally, by selecting a capacitor that yields a rise / fall time of approximately ⅓ of the maximum bit transmission time, signal reflection on the signal line can be reduced. Accordingly, by incorporating the feedback capacitor with a differential drive circuit, such as the IB 485 driver, variations in line load can be compensated for while also reducing signal reflection due to un-terminated or improperly terminated signal lines, thus allowing a free topology implementation.

Seismic prospecting method and device using simultaneous emission of seismic signals obtained by coding a signal by pseudo-random sequences, and notably a periodic signal phase modulated by such sequences.Signals such as, for example, periodic signals phase modulated according to a pseudo-random code (binary for example), produced by a control unit, are for example emitted in the ground by means of vibrators, the seismic signals reflected by the subsoil discontinuities in response to the periodic signals emitted are picked up by receivers coupled with the formation and recorded in an acquisition and recording system. The periodic signals are emitted simultaneously by the vibrators. The control sequences of the coded periodic signals intended for all the vibrators are obtained either from the same random binary sequence with respective time lags evenly distributed over the length of the control sequence according to the number of vibrators used simultaneously (first mode), or from different sequences selected from among a group of sequences of minimum crosscorrelation (second mode), or by combining the two aforementioned modes. The respective contributions of the various vibrators are separated by correlating the signals received and recorded with signals constructed from the various control sequences obtained with time lags. The vibrators can be divided into several groups, the vibrators of each group being controlled by a binary sequence belonging to a minimum crosscorrelating group.Application: seismic prospecting or seismic monitoring of reservoirs for example.

A high-density orthogonal connector is disclosed and may include electrical contacts that are configured to receive contacts from an orthogonal header connector while minimizing signal skew and signal reflection. The electrical contacts in the connector may define contact pairs (e.g., differential signal pairs). Each contact pair may include a lead portion and a mating interface that extends from the lead portion. The lead portions of the contact pair may define a first plane. One contact of the contact pair defines a first mating interface defining a second plane and the other contact in the contact pair defines a second mating interface defining a third plane. The second plane and the third plane may be both substantially parallel to and offset from the first plane in opposite directions. The contact pair may be configured such that the overall length of each contact within the pair may be substantially the same.

A probe board provides signal paths between an integrated circuit (IC) tester and probes accessing terminals on the surfaces of ICs formed on a semiconductor wafer for receiving test signals form the IC tester. A branching signal path within the probe board distributes a test signal produced by one channel of the IC tester to several probes. Resistors within the branching signal path resistively isolate the probes from one another so that a fault occurring at any one IC terminal will not affect the logic state of the test signal arriving at any other IC terminal. The isolation resistors are sized relative to signal path characteristic impedances so as to substantially minimize test signal reflections at the branch points.

A high-density orthogonal connector is disclosed and may include electrical contacts that are configured to receive contacts from an orthogonal header connector while minimizing signal skew and signal reflection. The electrical contacts in the connector may define contact pairs (e.g., differential signal pairs). Each contact pair may include a lead portion and a mating interface that extends from the lead portion. The lead portions of the contact pair may define a first plane. One contact of the contact pair defines a first mating interface defining a second plane and the other contact in the contact pair defines a second mating interface defining a third plane. The second plane and the third plane may be both substantially parallel to and offset from the first plane in opposite directions. The contact pair may be configured such that the overall length of each contact within the pair may be substantially the same.

A flex-rigid wiring board has an insulative adhesive interposed between portions, lapping over each other, of the rigid and flexible substrates; and the interconnecting electrode pads on the rigid and flexible substrates are electrically connected to each other through a conductor lump penetrating the insulative adhesive, thereby providing lowered inductance in the high-frequency band, shortened signal-delay time, reduced noise generation due to signal reflected-wave, reduced drop impact, high connection reliability and high freedom of wire connection, and the wiring board can advantageously be manufactured with a reduced cost and a high yield.

A memory module includes at least one CAR and a plurality of DRAMs provided so as to be close and adjacent to one another on one face and the other face of a module substrate. The DRAMs are divided into a plurality of memory groups. Memory groups adjacent to each other of these memory groups are paired with each other. One of this pair is a 1-ranked memory group and the other is a 2-ranked memory group. This pair of the memory groups is connected to the CAR via short wiring with a T-branch structure having a short stub. One of the pair of the memory groups on the signal-reception side functions as an open end. Active termination is performed by a termination resistor of the other of the pair of the memory groups on the signal-non-reception side. Subsequently, signal reflections can be reduced.

A novel mechanism for performing high accuracy cable diagnostics. The mechanism utilizes time domain reflectometry (TDR) to detect and identify cable faults, perform estimations of cable length, identify cable topology, identify load and irregular impedance on metallic paired cable, such as twisted pair and coaxial cables. The TDR mechanism transmits pulses whose shapes are programmable and analyzes the signal reflections. The shapes of the pulses transmitted can be optimized in accordance with the channel characteristics. Further, the TDR mechanism is adapted to operative in the presence of high pass filters in the channel.

Systems and methods for an RF nulling scheme are provided. An RF nulling scheme can minimize the level of unwanted RF signal reflections entering the receiver without attenuating the desired signal response from an RFID tag. In one aspect of the RF nulling scheme a synthesizer signal can be split between a main path and a nulling path. In the nulling path the signal from the splitter can be routed through an electronically variable phase shifter and variable gain amplifier to create a nulling signal. The nulling signal can cancel the unwanted reflected signal. The phase or amplitude of the nulling signal can then be adjusted to improve cancellation as necessary.

A system and method is provided for confirming the identity of a user, where the confirmation is made using biometric data. The system includes an internal speaker having an audio port, which is positioned within the ear of the user, and is adapted for producing a signal having one or more frequencies. The system further includes an internal microphone having an audio port, which is positioned within the ear of the user, and is adapted for detecting a resulting signal including the signal produced by the internal speaker and any corresponding signal reflections. A determination is then made as to whether the resulting signal detected by the internal microphone matches the corresponding predetermined expected signal, based upon a prestored hearing profile.

Return loss due to excessive signal reflection into a cable television (CATV) network from an inoperative or abnormally operative terminal adapter is minimized, to communicate enhanced passive downstream signals to passive subscriber devices such as “life-line” telephone sets. A predetermined termination impedance is substituted for an active branch circuit of the terminal adapter whenever reduced input voltage, over-current or under-current conditions exist in the terminal adapter.

A method and apparatus to remove human features utilizing at least one transmitter transmitting a signal between 200 MHz and 1 THz, the signal having at least one characteristic of elliptical polarization, and at least one receiver receiving the reflection of the signal from the transmitter. A plurality of such receivers and transmitters are arranged together in an array which is in turn mounted to a scanner, allowing the array to be passed adjacent to the surface of the item being imaged while the transmitter is transmitting electromagnetic radiation. The array is passed adjacent to the surface of the item, such as a human being, that is being imaged. The portions of the received signals wherein the polarity of the characteristic has been reversed and those portions of the received signal wherein the polarity of the characteristic has not been reversed are identified. An image of the item from those portions of the received signal wherein the polarity of the characteristic was not reversed is then created.

A superdirectional acoustic system for reproducing a sound signal supplied from a real sound source by using a superdirectional speaker and producing a virtual sound source in a vicinity of a sound wave reflection surface. The system includes an ultrasonic speaker, which includes an ultrasonic transducer for oscillating a sound wave in an ultrasonic frequency band, for reproducing an audio signal in a relatively medium to high frequency sound range, which is included in the sound signal supplied from the real sound source; and a low frequency sound reproducing speaker for reproducing an audio signal in a relatively low frequency sound range, which is included in the sound signal supplied from the real sound source. Sound in the medium-high frequency range is reproduced in a manner such that the sound is produced from a virtual sound source which is formed in the vicinity of the sound signal reflection surface such as a screen.

A technique for detecting a fiber fault in a WDM optical access network includes launching a test signal into a fiber trunk line linking a central office (“CO”) to a remote node (“RN”) of the WDM optical access network. The test signal is generated by an optical time domain reflectometry unit to simultaneously fault test fiber access lines linking the RN to customer premises. The test signal is separated from downstream WDM signals at the RN. The test signal is power split at the RN into a plurality of access line test signals. The access line test signals are each recombined with a corresponding one of the downstream WDM signals onto a corresponding one of the fiber access lines. Test signal reflections are received at the CO from the fiber access lines as a reflection signature and analyzed to identify a location of the fiber fault.

A wireless temperature sensor network includes a base station unit which transmits query signals cyclically addressing a plurality of temperature sensor transponder units. The transponder units are passive and derive operating power from the query signal to encode measured temperature data into a reply signal which is received by the base station. In a dual carrier embodiment, the query signal and reply signals are transmitted on separate frequencies. In a backscattering embodiment, the antennas of the transponder units can be switched between an absorption mode in which the query signal is received and a reflection mode in which the query signal is reflected back to the base station. The transponder antennas are switched in such a manner as to encode temperature data in the reflected signal to form a reply signal. The network embodiments are particularly applicable to space based platforms.

A skew correction system incorporated into a transmitter forwarding a differential signal on a differential lane monitors returning signal reflections when the receiving end of the differential lane is appropriately terminated. Based on an analysis of the reflections, the skew correction system adjusts the relative timing of complementary edges of the differential signal departing the transmitter so as to substantially eliminate skew at the receiving end of the differential lane.

According to the present invention, in order to simultaneously realize high-speed transmission suppressing signal reflection and reduction of power consumption, a bidirectional transmission circuit, in which a plurality of sending / receiving elements send and receive signals via a transmission bus, is constructed so that, when a first sending / receiving element operates as a sending side, a first control unit sets a connection of the transmission bus to a first termination voltage source via a first terminating resistor by a first switch to off and a second control unit sets a connection of the transmission bus to a second termination voltage source via a second terminating resistor by a second switch to on.

A multi-modal ground penetrating radar includes a radar set configured to launch predistorted double-sideband (DSB) suppressed-carrier modulated continuous waves (CW) to illuminate and penetrate a ground surface. A variable frequency modulator is connected to modulate a continuous wave (CW) carrier frequency generator within the radar set to yield a double-sideband suppressed carrier output. A lateral single-file array of antennas is configured to be flown closely over the surface of the ground. A multiplexing switch is connected to the array of antennas and configured to selectively switch individual ones of the antennas to the radar set. Any early arriving signals returned from geologic clutter and surface reflections are suppressed in synchronous detection in relation to signals received by the array of antennas from less shallow depths. Interesting objects below the ground surface are detected and located by the late arriving signal reflections.

A method for increasing the interrogation range of an RF Tag in a radio communication system using RF Tags with multiple reflecting antenna elements. The reflecting antenna elements are predeterminately positioned, and preferably aligned, with respect to each other in the direction of expected incident RF radiation. The reflecting antenna elements are sequentially pulsed on and off such that while the first reflecting antenna element is in a signal reflecting operating state, the remaining reflecting antenna elements are in a substantially non-reflecting state, and when the second reflecting element is in a reflecting operating state, the remaining reflecting elements are in a non-reflecting state, etc. The sequential pulsing and predetermined fixed spacing between the reflector elements generates constructive interference between the reflected signals of the reflecting antenna elements which increases the power of the resulting reflected signal.

Implementations of techniques and systems are disclosed for detecting a fiber fault in a point-to-point optical access network based on optical time domain reflectometry (“OTDR”) measurements. The techniques include identifying loss of service between a central office (“CO”) and a given optical network unit (“ONU”) of a plurality of ONUs. In response to the identifying the loss of service, configuring a test signal distribution unit to optically couple an OTDR unit to a selected subset of the point-to-point fiber links which includes the given ONU. An optical test signal is launched from the OTDR unit into the selected subset of the point-to-point fiber links via the test signal distribution unit. Test signal reflections are received from each of the point-to-point fiber links within the selected subset as a reflection signature, which is analyzed to identify a location of the fiber fault.

A high speed impedance matching circuit suitable for use in high speed semiconductor integrated circuits matches the output impedance of a semiconductor device to the impedance of other devices such a computer system bus thereby reducing signal reflections caused by impedance mismatches and which can adversely affect the operation of a high speed computer system. The impedance of an output buffer is matched to the impedance of an external resistor.

An intracellular electro-manipulation apparatus for delivery an electric field pulse to a target of one or more biological cells is provided. The apparatus includes a pulse generator that generates an ultrashort electric field pulse, and a pulse delivery system that directs the ultrashort electric field pulse to the target. The apparatus can include a reflected-signal impeder connected between the pulse generator and the pulse delivery system to impede reflection of a signal to the pulse generator when impedance mismatching between the pulse delivery system and pulse generator occurs. Alternatively, or additionally, the apparatus can include a current limiter connected between the pulse generator and the pulse delivery system to limit current between the pulse generator and the pulse delivery system when a high-conductivity condition occurs in the target.

Analyzing interactions between vias in multilayered electronic packages that include at least two spaced-apart conducting planes, and multiple vias that connect signal traces on different layers. Voltages at active via ports are represented as magnetic ring current sources, which generate electromagnetic modes inside the plane structure. Substantial electromagnetic coupling between vias occurs. A full-wave solution of multiple scattering among cylindrical vias in planar waveguides is derived using Foldy-Lax equations. By using the equivalence principle, the coupling is decomposed into interior and exterior problems. For the interior problem, the dyadic Green's function is expressed in terms of vector cylindrical waves and waveguide modes. The Foldy-Lax equations for multiple scattering among the cylindrical vias are applied, and waveguide modes are decoupled in the Foldy-Lax equations. The scattering matrix of coupling among vias is then calculated for use in determining signal reflection, transmission, and / or coupling in the electronics package.