Dissipating Terminations For Long Lines Patents (Class 333/22R)
  • Patent number: 6124768
    Abstract: In a method for forming microwave testing high-power dummy load, a first center conductor, to which microwave power is input, is connected to a power distributor formed from a second center conductor having an output-side distal end branching into a plurality of portions. This causes the microwave power input to the first center conductor to separate into a plurality of outputs in correspondence with the output-side distal end of the second center conductor. A plurality of termination resistors are connected between the output-side distal end of the second center conductor and a ground conductor to make the termination resistors consume the microwave power. The heat generated by the termination resistors upon consumption of the microwave power is radiated by the ground conductor. A microwave testing high-power dummy load apparatus made by the above described method is also disclosed.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: September 26, 2000
    Assignee: NEC Corporation
    Inventor: Joji Makiyama
  • Patent number: 6118350
    Abstract: A system of resistive end termination and transmission line routing is disclosed for matching the impedance of an IC load to that of a signal source and a transmission line. Each integrated circuit has an internal termination resistor designed to match the characteristic impedance of the transmission line and preferably also the impedance of the source. When the source drives multiple IC devices on a printed circuit board, the devices are cascaded in a chain with the internal resistors of all but the last IC device in the chain bypassed by a short circuit underneath the device, so that a continuous transmission line is provided to the last IC device. The last IC in the chain, which does not have a short circuit underneath it, provides the necessary resistive termination by simply connecting the appropriate pin to a common reference in the circuit. The invention is also applicable to differential applications in which first and second complementary signal sources feed each IC device.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: September 12, 2000
    Assignee: Gennum Corporation
    Inventors: Atul Krishna Gupta, Dino Toffolon
  • Patent number: 6104258
    Abstract: A system and method are presented for stabilizing the electrical impedance of an electrical interconnecting apparatus including a pair of parallel planar conductors separated by a dielectric layer. The electrical interconnecting apparatus may be, for example, a PCB, a component of a semiconductor device package, or formed upon a surface of an integrated circuit substrate. The present method includes determining a characteristic impedance of the structure. An electrical resistance is electrically coupled between regions of the planar conductors near peripheries, wherein the electrical resistance has a value dependent upon the characteristic impedance of the structure. The electrical resistance may be a set of discrete electrical resistances (e.g., resistors) dispersed about regions near peripheries of the planar conductors, or a continuous "stripe" of electrical resistance between the regions.
    Type: Grant
    Filed: May 19, 1998
    Date of Patent: August 15, 2000
    Assignee: Sun Microsystems, Inc.
    Inventor: Istvan Novak
  • Patent number: 6094106
    Abstract: A module equipped with a non-radiative dielectric waveguide in accordance with this invention comprises a pair of parallel flat conductors arranged at a space of 1/2 or below of a high frequency signal wavelength .lambda. and a dielectric strip extending between these parallel flat conductors. This dielectric strip is formed from a cordierite ceramic having a dielectric constant of 4.5 to 8, especially 4.5 to 6. Conversion of an electromagnetic wave of LSM mode to an electromagnetic wave of LSE is minimal. When the module has a dielectric strip having a steep curved portion having a small radius of curvature, the transmission is possible with a low loss, and the band width of a high frequency signal is broad.
    Type: Grant
    Filed: June 24, 1998
    Date of Patent: July 25, 2000
    Assignee: Kyocera Corporation
    Inventors: Tetsuya Kishino, Takeshi Okamura
  • Patent number: 6094107
    Abstract: A termination for a coaxial transmission line wherein an elongated central conductor is located in an enclosure or housing and is surrounded by a plurality of elongated resistor tubes. The central conductor is connected to the inner conductor of the transmission line and the resistor elements are connected to the outer conductor. The housing defines an inner flow chamber and a plurality of outer flow passages surrounding the inner flow chamber with the upper ends thereof communicating with the upper end of the inner flow chamber. A centrifugal blower is located at the bottom of each of the outer flow passages to generate an air flow upwardly and then through lateral ports into the upper end of the inner flow chamber, whereupon a flow proceeds downwardly in a turbulent vortex through the inner flow chamber to cool the resistor elements.
    Type: Grant
    Filed: September 29, 1998
    Date of Patent: July 25, 2000
    Inventor: Jefferson D. Lexa
  • Patent number: 6087848
    Abstract: Systems and methods are described for implementing a backplane in the context of a stack of networking hubs based on a backplane connecter and for carrying out a method of configuring and terminating the backplane. A backplane connector includes a first voltage source; a plurality of connector contacts; a plurality of termination resistors, a first end of the plurality of termination resistors being coupled to the plurality of connector contacts; a first switch located between the first voltage source and a second end of the plurality of termination resistors; a first logic circuit coupled to the first switch, the first logic circuit closing the first switch when a layer composed by the backplane connector is both i) active and ii) either a top layer in a stack composed by the layer or a bottom layer in the stack.
    Type: Grant
    Filed: July 20, 1998
    Date of Patent: July 11, 2000
    Assignee: Kendin Semiconductor, Inc.
    Inventors: Jung-Chen Lin, Lawerence W. Mo
  • Patent number: 6069539
    Abstract: A system for the distribution of VTT termination voltage for a GTL bus system includes a plurality of GTL signal lines, a plurality of first termination resistors, and a plurality of second termination resistors. The GTL signal lines have a first end and a second end. The resistors have a signal end and a VTT end. The first end of the signal line is connected to the signal end of the first resistor. The second end of the signal line is connected to the signal end of the first resistor. A plurality of nodes are formed from the VTT ends of the first and second resistors. These nodes may be formed in many different ways, and in many different numbers. The nodes are each driven with a separate VTT supply, and the nodes are interconnected such that a failure in the power supply furnishing power to one node does not affect the other nodes, and does not affect the operation of the system consuming this VTT voltage.
    Type: Grant
    Filed: May 27, 1999
    Date of Patent: May 30, 2000
    Assignee: Cisco Technology, Inc.
    Inventors: David K. Sanders, Sergio D. Camerlo
  • Patent number: 6051989
    Abstract: There is disclosed, an active termination circuit includes a transmitter adapted to be coupled to a bidirectional conductor, a receiver also adapted to be coupled to the bidirectional conductor, a first impedance adapted to be switched to couple to the bidirectional conductor to match the input impedance of the receiver to a characteristic impedance of the bidirectional conductor to which it is adapted to be coupled when the receiver is in the receive mode, and a second impedance adapted to be switched to couple the bidirectional conductor to match the output impedance of the transmitter to the characteristic impedance of the bidirectional conductor to which it is adapted to be coupled when the transmitter is in the transmit mode.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: April 18, 2000
    Assignee: Lucent Technologies Inc.
    Inventor: Jeffrey Alan Walck
  • Patent number: 6046652
    Abstract: A process and implementing construction includes an electrically independent EMI loading device comprised of an inner foam core surrounded by an electrically conductive envelope. The device is strategically positioned in resonant cavities located within a system enclosure housing electronic components and circuit boards and. In an example, the loading device is installed in a resonant cavity between a board-mounted component and an adjacent circuit board and is effective to decrease electromagnetic emission from resonating cavities.
    Type: Grant
    Filed: March 31, 1997
    Date of Patent: April 4, 2000
    Assignee: International Business Machines Corporation
    Inventors: James William Deiso, III, Jose Patino Mendez, Jr., Ernest Lee Miller, Jerry W. Scibielski
  • Patent number: 6028498
    Abstract: A low inductance interconnect suitable for microwave frequency interconnect applications. The invention provides a low inductance interconnect structure providing interconnection operable from DC to beyond 100 Ghz. The structure may be in the form of a resilient comb, and can be cut from thin sheet metal with a Wire Electric Discharge Machine (EDM). Other resilient forms include spring structures, resilient canes and conductive fuzz.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: February 22, 2000
    Assignee: Hewlett-Packard Company
    Inventor: Joel D. Bickford
  • Patent number: 6025760
    Abstract: A tool is described for shunting a multi-tap for an RF cable system by connecting a low-pass filter between an unused input port and an unused output port of the multi-tap. The components of the filter are such as not to interfere with the circuits of the multi-tap when both are in the circuit. A light is provided for indicating when the tool is in operative position.
    Type: Grant
    Filed: May 1, 1998
    Date of Patent: February 15, 2000
    Inventor: Danny Q. Tang
  • Patent number: 6016085
    Abstract: An RF termination load includes a base of an electrically and thermally conductive material having opposed surfaces. A recess is in one of the surfaces of the base and a groove in the one surface extends from the recess to an edge of the base. A resistor is seated in the recess in the base. The resistor includes a substrate of an electrically insulating material having opposed surfaces and a resistance film on one of the surface of the substrate. A first contact of a resistance film is on the one surface of the substrate at one end of the resistor and a second contact of an electrically conductive material is on the one surface of the substrate at the other end of the resistor. The second contact extends over an edge of the substrate and over the other surface of the substrate. The resistor is mounted in the recess with the second contact being seated on and contacting the base. An RF cable has an end in the groove in the base.
    Type: Grant
    Filed: September 28, 1998
    Date of Patent: January 18, 2000
    Assignee: EMC Technology LLC
    Inventor: Joseph B. Mazzochette
  • Patent number: 5970138
    Abstract: Terminal equipment for telecommunications and information processing with improved electromagnetic compatibility (EMC). The equipment has a human-machine interface (HMI), a metallic telecommunications interface (TCI), and optionally a power line interface (PLI). First common-mode rejection filters consisting of common-mode choke coils and shunt capacitors are placed at the HMI interface of the equipment, while second common-mode rejection filters consisting of the same components are placed at the TCI and PLI interfaces. High-frequency junction points of the first and second common-mode rejection filters are interconnected with a bypass circuit. Being isolated from the signal ground and frame ground of the equipment, the bypass circuit is an independent non-grounded circuit. Such internal structure makes it possible to reject noise signals induced by an external noise source and also to suppress spurious radiation from an internal noise source.
    Type: Grant
    Filed: December 3, 1996
    Date of Patent: October 19, 1999
    Assignee: Fujitsu Limited
    Inventors: Yozo Suda, Yuji Yamaguchi
  • Patent number: 5953645
    Abstract: A multiple band termination circuit, comprising a first resistor coupled in signal communication with an input and an open stub to form a nominal termination at a high frequency band, and a second resistor coupled in series to the first resistor with a high impedance transmission line, the second resistor and the first resistor cooperating together to form a nominal termination at a low frequency band.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: September 14, 1999
    Assignee: Motorola, Inc.
    Inventor: Christopher David Grondahl
  • Patent number: 5920245
    Abstract: The ease of mounting a circuit board on a nonradiative dielectric line is improved, the degree of freedom of conductor film patterns formed on the circuit board is increased, and the degree of integration can be easily increased to fit within a small size. Dielectric strips are provided between the two conductor plates positioned in parallel to each other, and a circuit board is positioned parallel to the conductor plates. The conductor patterns on the circuit board and the transmission waves of the nonradiative dielectric line are electromagnetically coupled to each other.
    Type: Grant
    Filed: April 9, 1998
    Date of Patent: July 6, 1999
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Yohei Ishikawa, Toru Tanizaki, Hiroshi Nishida, Sadao Yamashita, Atsushi Saitoh
  • Patent number: 5904596
    Abstract: The present invention comprises a terminator which features an internal termination resistor and capacitor mounted on a substrate which is in electrical and mechanical communication with a center terminal pin at one end, and the connector body at the other end. The body of the terminator is grounded via the connection of the terminator to a cooperating connector. The present invention includes a support insulator which protects the internal components of the terminator by preventing transmission of tensile, torsional, and bending stresses through the terminal into the termination chip assembly. The stresses are absorbed by means of a supportive insulator which frictionally supports a textured section of the center terminal within the terminator. The stresses typically occur during installation or removal of the terminator to or from a connector. With the present invention it is possible to twist and bend the metal terminal of the terminator to the point of fracture without damaging the termination chip.
    Type: Grant
    Filed: July 14, 1997
    Date of Patent: May 18, 1999
    Assignee: Thomas & Betts International, Inc.
    Inventors: Gary A. Knaus, Andrew J. Kempf, Ronald P. Locati, Michael R. Dean
  • Patent number: 5831491
    Abstract: An extremely broad band high power termination (10) for microwave and millimeter frequency amplifiers combines a standard resistive low frequency termination (15) with a broad band high frequency absorptive element (13) using an absorptive material such as Eccosorb. A mid-band matching network (14) is provided between the resistive termination (15) and the Eccosorb absorptive element (13). The Eccosorb absorbs the energy of the higher microwave frequencies while the resistor absorbs energy at low frequencies. Accordingly, a much higher power handling capability in a compact planer environment is achieved. This termination (10) is suitable use for use in K-band power amplifier combiners (30) that require high isolation and high power handling capability of the isolated ports (35).
    Type: Grant
    Filed: August 23, 1996
    Date of Patent: November 3, 1998
    Assignee: Motorola, Inc.
    Inventors: Kenneth Vern Buer, John Holmes, David Warren Corman
  • Patent number: 5825259
    Abstract: A termination is provided for a differential transmission line such as unshielded twisted pair (UTP) to isolate a connected device from electromagnetic interference present on the UTP in the form of differential mode and common mode noise. An example of an electromagnetic interference isolator comprises a common mode and a differential mode termination, a common mode choke which exhibits substantially constant impedance over a wide bandwidth and a centre tapped isolation transformer.
    Type: Grant
    Filed: March 25, 1997
    Date of Patent: October 20, 1998
    Assignee: Madge Networks Limited
    Inventor: Lewis Freeth Harpham
  • Patent number: 5812035
    Abstract: A method of producing a microwave power divider or combiner having equally matched sections of a split terminating resistor. The method initially matches the resistance value of both sections of the split terminating resistor by identifying which section has a lower resistance value. The ratio of the resistance values of the two sections is determined. The section having the lower resistance value is then trimmed until it is equal to the other. The termination sections may then be equally trimmed to provide a desired final resistance value for the terminating resistor.
    Type: Grant
    Filed: December 19, 1996
    Date of Patent: September 22, 1998
    Assignee: Raytheon Company
    Inventors: Robert G. Fleeger, Ron K. Nakahira
  • Patent number: 5801598
    Abstract: A compact high-power RF load comprises a series of very low Q resonators, or chokes ?16!, in a circular waveguide ?10!. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer ?12! at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications.
    Type: Grant
    Filed: May 1, 1997
    Date of Patent: September 1, 1998
    Assignee: Stanford University
    Inventors: Sami G. Tantawi, Arnold E. Vlieks
  • Patent number: 5770989
    Abstract: The ease of mounting a circuit board on a nonradiative dielectric line is improved, the degree of freedom of conductor film patterns formed on the circuit board is increased, and the degree of integration can be easily increased to fit within a small size. Dielectric strips are provided between the two conductor plates positioned in parallel to each other, and a circuit board is positioned parallel to the conductor plates. The conductor patterns on the circuit board and the transmission waves of the nonradiative dielectric line are electromagnetically coupled to each other.
    Type: Grant
    Filed: July 3, 1996
    Date of Patent: June 23, 1998
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Yohei Ishikawa, Toru Tanizaki, Hiroshi Nishida, Sadao Yamashita, Atsushi Saitoh
  • Patent number: 5742211
    Abstract: A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.
    Type: Grant
    Filed: March 22, 1996
    Date of Patent: April 21, 1998
    Assignee: Lockheed Martin Energy Systems, Inc.
    Inventors: Robert J. Lauf, April D. McMillan, Arvid C. Johnson, Carl A. Everleigh, Arthur J. Moorhead
  • Patent number: 5708400
    Abstract: High speed power supply transients are suppressed in a system having fast edges and where a radial transmission line exists between the power supply and ground planes, by terminating the edges of the PCB in it characteristic impedance. In practice, this means approximating a continuous construct with many spaced instances of a discrete resistance. The dissipative terminations themselves are resistive, and if placed directly between the power supply and ground would needlessly dissipate a great deal of DC power. To prevent that they are AC coupled with a high quality coupling capacitor of sufficient capacitance to allow the resulting impedance to appear predominately resistive at and above the lowest frequency of interest, say, 100 MHz. Because of the confused nature of the reflection that may be generated at arbitrary locations within the interior of the PCB, there may well be "hot spots" within that interior that would benefit from the placement of a selected AC coupled load at or near such a spot.
    Type: Grant
    Filed: October 30, 1996
    Date of Patent: January 13, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Terrel L. Morris
  • Patent number: 5686872
    Abstract: Reflections and cross talk in a high-speed, bidirectional transmission line are minimized by terminating the transmission line with a network including a "serial" resistor connected in series between an end of the transmission line and a parallel (e.g. data) port, a "pull-up" resistor connected to the transmission line side of the serial resistor, and a capacitor connected between the parallel port side of the serial resistor and ground. Optionally, a diode is connected between the pull-up resistor and a bias potential. A variety of exemplary values for these components (i.e., serial resistor, pull-up resistor, capacitor) are discussed, in the context of particular signals. Preferably, the capacitor and the resistors are positioned as close as possible to the connector.
    Type: Grant
    Filed: March 13, 1995
    Date of Patent: November 11, 1997
    Assignee: National Semiconductor Corporation
    Inventors: Rafael Fried, Erez Bar-Niv
  • Patent number: 5677651
    Abstract: An Ethernet-type local area network having multiport repeaters and nodes within a specified distance of the hub is able to communicate high speed digital data over multiple pairs of twisted-pair wires using long symbol group-type ternary coding. Bundle mode termination minimize impedance mismatches. Low-frequency collision detection circuitry permits detection of packet collisions on an a.c.-coupled network. Precise serialized digital to analog conversion is realized using chains of gates to form delay elements with precise delays.
    Type: Grant
    Filed: February 20, 1996
    Date of Patent: October 14, 1997
    Inventor: Ronald C. Crane
  • Patent number: 5670917
    Abstract: The present invention is directed to an AC termination which includes a substrate having first and second surfaces. A resistor is mounted on the first surface of the substrate. An input termination is at one end of the resistor. At least one plate of a capacitor is on the substrate and is electrically connected in series with the other end of the resistor. In one form of the termination, the capacitor is a metal film on the substrate extending from the other end of the resistor to and across the second surface of the substrate to form one electrode of the capacitor. A dielectric layer is over the metal film and another metal film extends over the dielectric layer to form the other electrode of the capacitor and the output termination of the termination. In another form of the termination, the capacitor is formed on a cover plate which extends over the first surface of the substrate and is electrically connected between the resistor and an output termination.
    Type: Grant
    Filed: September 12, 1996
    Date of Patent: September 23, 1997
    Assignee: EMC Technology, Inc.
    Inventor: Joseph B. Mazzochette
  • Patent number: 5659273
    Abstract: A termination is provided for a differential transmission line such as unshielded twisted pair (UTP) to isolate a connected device from electromagnetic interference present on the UTP in the form of differential mode and common mode noise. An example of an electromagnetic interference isolator comprises a common mode and a differential mode termination, a common mode choke which exhibits substantially constant impedance over a wide bandwidth and a centre tapped isolation transformer.
    Type: Grant
    Filed: August 1, 1995
    Date of Patent: August 19, 1997
    Assignee: Madge Metworks Limited
    Inventor: Lewis Freeth Harpham
  • Patent number: 5646581
    Abstract: A termination device including a package having a first plurality of pins and a plurality of resistors disposed in the package is described. Each resistor has a pair of termini with one of the termini of each resistor connected to a corresponding one of the first plurality of pins and the other termini connected to a common conductor. The device also includes a reference conductor connected to a mid-portion of the common conductor and to a pin of the package. An alternate embodiment of the termination device includes two reference conductors connected to respective end portions of the common conductor and to pins of the package.
    Type: Grant
    Filed: January 26, 1996
    Date of Patent: July 8, 1997
    Assignee: Digital Equipment Corporation
    Inventors: James O. Pazaris, Richard P. Evans
  • Patent number: 5617064
    Abstract: An active termination resistor is provided within a feedback loop circuit thus advantageously increasing the stability of the feedback loop circuit. In particular, the active termination resistor traces the impedance of the feedback loop such that R(f).congruent.1/GM3(f). The active resistor may also be configured to track the value of the resistor to set the feedback transconductance over process and temperature variations to ensure stability of the feedback loop over these variations.
    Type: Grant
    Filed: March 14, 1995
    Date of Patent: April 1, 1997
    Assignee: Lattice Semiconductor Corporation
    Inventor: James L. Gorecki
  • Patent number: 5614873
    Abstract: In order to avoid signal reflections, a transmission line connected to an electronic circuit is terminated by a terminating impedance. The value of the terminating impedance is to match in the best possible way in the frequency zone of the circuit with the value of a characteristic impedance of the transmission line to be terminated. The invention provides an electronic circuit in which the terminating impedance is a series combination of an active impedance and a passive impedance. The passive impedance is of the same order of magnitude as the characteristic impedance. The terminating impedance matches well with the characteristic impedance of the transmission line even at high frequencies. By modifying the settings of the active impedance, both the value of the terminating impedance and the DC voltage on a transmission line termination can be set.
    Type: Grant
    Filed: November 28, 1995
    Date of Patent: March 25, 1997
    Assignee: U.S. Philips Corporation
    Inventor: Johannes J. E. M. Hageraats
  • Patent number: 5610562
    Abstract: A waveguide absorber which withstands high mechanical and thermal loads is typified in that a member (4) exhibiting absorber material is clamped between waveguide walls (5, 6) in such a way that at least one wall region (5) adjoining the member (4) is constructed flexibly, and that a force acting on the flexible wall region (5) presses the latter against the member (4).
    Type: Grant
    Filed: February 27, 1995
    Date of Patent: March 11, 1997
    Assignee: Ant Nachrichtentechnik GmbH
    Inventors: Klaus H. Geissler, Jurgen Damaschke, Dieter Wolk
  • Patent number: 5598131
    Abstract: The present invention is directed to an AC termination which includes a substrate having first and second surfaces. A resistor is mounted on the first surface of the substrate. An input termination is at one end of the resistor. At least one plate of a capacitor is on the substrate and is electrically connected in series with the other end of the resistor. In one form of the termination, the capacitor is a metal film on the substrate extending from the other end of the resistor to and across the second surface of the substrate to form one electrode of the capacitor. A dielectric layer is over the metal film and another metal film extends over the dielectric layer to form the other electrode of the capacitor and the output termination of the termination. In another form of the termination, the capacitor is formed on a cover plate which extends over the first surface of the substrate and is electrically connected between the resistor and an output termination.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: January 28, 1997
    Assignee: EMC Technology, Inc.
    Inventor: Joseph B. Mazzochette
  • Patent number: 5598132
    Abstract: A self-terminating coaxial connector provides for automatic termination of a coaxial cable. The connector includes an internal termination resistor which is only connected in series between the central conductor of a first cable and a grounded body of the connector when a second cable is not installed on the end of the connector. When a second cable is installed on the connector, the terminator resistor is disconnected from the grounded body, thereby removing the termination from the central conductor of the first cable.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: January 28, 1997
    Assignee: LRC Electronics, Inc.
    Inventor: David J. Stabile
  • Patent number: 5585741
    Abstract: A low capacitance impedance emulator suitable for active conductor termination. The impedance emulator includes an emulating FET and a control circuit coupled to the gate of the emulating FET for maintaining the FET in a linear region of operation. The control circuit includes a control FET, an impedance setting resistor, and an amplifier. The control FET is driven in a closed-loop fashion so that the impedance of the control FET has a known relationship with respect to that of the resistor. The output of the amplifier controls the conduction of both the emulating and control FETs so that the emulating FET provides an impedance proportional to that of the control FET and thus, related to the impedance of the resistor. A disconnect feature is provided, whereby the impedance emulator is responsive to a disconnect signal for disconnecting the impedance provided by the emulating FET.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: December 17, 1996
    Assignee: Unitrode Corporation
    Inventor: Mark Jordan
  • Patent number: 5565822
    Abstract: In TEM waveguide arrangements such as are used in testing the electromagnetic compatibility of electronic devices in electromagnetic fields, a plate-shaped inner conductor is connected via electrically parallel-connected tubular resistors to an electrically conductive, spherical rear wall. This rear wall is electrically connected to an outer conductor and grounded. Radio-frequency absorbers are mounted on the rear wall for the purpose of absorbing TEM waves, the RF short-point absorbers adjacent to the tubular resistor being smaller than the remaining RF long-point absorbers, in order to reduce the capacitive influence of the tubular resistors. Identical tubular resistors are arranged perpendicular to the plane of the drawing of FIG. 1 in accordance with a current density distribution in such a way that they are more closely adjacent at the edge than in the middle of the inner conductor.
    Type: Grant
    Filed: May 24, 1995
    Date of Patent: October 15, 1996
    Assignee: ABB Management AG
    Inventors: Felix Gassmann, Henk Hoitink, Rolf Muller, Hans Schar
  • Patent number: 5559448
    Abstract: An improved CMOS termination is disclosed wherein a transmission gate provides the proper impedance for matching a termination with the characteristic impedance of the line.
    Type: Grant
    Filed: April 7, 1995
    Date of Patent: September 24, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventor: Wilhelm Koenig
  • Patent number: 5546017
    Abstract: The invention is an active, hot insertable, SCSI terminator circuit having a bypass device that permits an initially unpowered active SCSI terminator to be coupled to a signal line of a powered SCSI bus such that no damage results to the SCSI terminator circuit itself or to other SCSI devices on the SCSI bus, and without having the effect of altering the existing state of the SCSI bus as a result of the coupling. Preferably, the terminating element of the SCSI terminator is a p-channel MOSFET. The SCSI terminator is prevented from being damaged during the coupling by using the bypass device to effectively short the gate of the p-channel MOSFET terminating element to its drain. When the drain of the p-channel MOSFET terminating element is shorted to its gate the amount of current the SCSI terminator may draw from any and all SCSI signal lines during the coupling is substantially limited to less than 50 .mu.A.
    Type: Grant
    Filed: March 23, 1995
    Date of Patent: August 13, 1996
    Assignee: Micro Linear Corporation
    Inventor: Mark R. Vitunic
  • Patent number: 5528167
    Abstract: An SCSI bus line apparatus including in combination at least two of any of an active deassertion (ADR) circuit, a signal line impedance matching (SLIM) circuit and a signal line increased circuit kicker (SLICK) circuit. In the ADR circuit, if a current sinking circuit senses an increased voltage on the common node of the signal lines of a bus due to active deassertion of a signal line, the current sinking circuit sinks enough current from the signal lines to prevent an over-current condition on asserted signal lines or soon-to-be asserted signal lines. In the SLIM circuit, transient voltages are removed from a signal line by limiting to within a range the voltages that can appear on the signal line.
    Type: Grant
    Filed: April 15, 1994
    Date of Patent: June 18, 1996
    Assignee: Methode Electronics, Inc.
    Inventors: Francis M. Samela, William L. Zuckerman
  • Patent number: 5523727
    Abstract: A dielectric waveguide has a pair of parallel flat metallic plates spaced from each other, a dielectric strip sandwiched between the parallel flat metallic plates, and a wave absorber sandwiched between the parallel flat metallic plates and extending parallel to the dielectric strip. The wave absorber has a tapered portion which is progressively closer to the dielectric strip in a direction away from an inlet end of the wave absorber. The wave absorber has a side surface which may be held in contact with a side surface of the dielectric strip to provide a termination for eliminating reflections of input electromagnetic waves applied to the nonradiative dielectric waveguide, or may be spaced from a side surface of the dielectric strip to provide an attenuator for attenuating the power of input electromagnetic waves applied to the nonradiative dielectric waveguide.
    Type: Grant
    Filed: November 22, 1994
    Date of Patent: June 4, 1996
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventor: Masahito Shingyoji
  • Patent number: 5523704
    Abstract: A method and circuit for actively controlling the transition resistance of a multiplex communication signal line having a known termination resistance and characterized by digital signals defined by dominant and recessive states between a voltage source and a ground potential. The digital signal is sensed at the node when it moves through a transition band defined between the dominant and recessive states. The effective terminator resistance at the node along the signal line is reduced only responsive to the digital signal level being within the transition band, whereby the transition time for the signal to travel through the transition band is reduced by reducing the effective resistance and therefore the effective RC time constant at the node.
    Type: Grant
    Filed: October 4, 1993
    Date of Patent: June 4, 1996
    Assignee: Ford Motor Company
    Inventor: Lingkon So
  • Patent number: 5469128
    Abstract: A circuit element for microwave and millimeter-wave bands and a method of producing the same. A dielectric line is made of a pure dielectric resin. A high-frequency wave absorbing member is made of a pure dielectric resin containing at least one of first, second and third powders dispersed therein. The first powder having a high specific inductive capacity, the second powder having a high magnetic permeability, and the third powder having a high specific resistance. A compression molding technique is used to fusion bond the high-frequency wave absorbing member to the dielectric line.
    Type: Grant
    Filed: September 14, 1994
    Date of Patent: November 21, 1995
    Assignees: Nissan Motor Co., Ltd., Nippon Valqua Industries, Ltd.
    Inventors: Umeo Kawanishi, Nobuhisa Hirayama, Takeshi Hamabe, Toru Takagi
  • Patent number: 5467453
    Abstract: Disclosed are a circuit and method for providing automatic termination for a small computer systems interface ("SCSI") bus. The circuit resides within a bus controller comprising (1) a control circuit for controlling transmission of data on a bus and for providing an interface between the bus and a computer system for communication of the data therebetween and (2) a first bus port and a second bus port, each of the first and second bus ports permitting a device to be coupled thereto for communication with the control circuit via the bus, the bus controller being at an end of the bus when a single one of the first and second bus ports is coupled to a device and being in a middle of the bus when both the first and second bus ports are coupled to devices.
    Type: Grant
    Filed: July 20, 1993
    Date of Patent: November 14, 1995
    Assignee: Dell USA, L.P.
    Inventor: Thomas Kocis
  • Patent number: 5463359
    Abstract: An impedance matching circuit which includes an RC network placed at the end of the transmission line and which will absorb reflections. The values of the resistor and capacitor are selected such that the output voltage at the end of the transmission line is attenuated only during the duration of the reflected waves and the overall gain from the incident signal to the end of the transmission line is 1:1. The values of the resistor and capacitor selected are based upon the impedance mismatch and the length of the transmission line.
    Type: Grant
    Filed: March 21, 1994
    Date of Patent: October 31, 1995
    Assignee: Texas Instruments Incorporated
    Inventor: Dale A. Heaton
  • Patent number: 5422608
    Abstract: An adaptive transmission line termination which includes a variable voltage controlled resistor (16) connected either in series with the sending end of transmission line (10) or in parallel with the receiving end of line (10). The resistance of resistor (16) is varied in dependence upon the half voltage appearing on line (10) in order to match the characteristic impedance of line (10) for the series or source termination case. In the parallel termination case, the resistance of resistor (34) is varied in dependence upon the voltage appearing at the input of gate (14) to match the characteristic impedance of line (10).
    Type: Grant
    Filed: August 30, 1994
    Date of Patent: June 6, 1995
    Assignee: Texas Instruments Incorporated
    Inventor: Louis Y. Levesque
  • Patent number: 5406118
    Abstract: A semiconductor chip includes a long bus line for transmitting digital signals. The semiconductor chip includes transmission lines for transmitting signals between the bus line and other lines. An impedance regulating element having an impedance, which matches the characteristic impedance of the bus line, is connected to each of the transmission lines.
    Type: Grant
    Filed: October 16, 1992
    Date of Patent: April 11, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yasuyuki Saito
  • Patent number: 5404145
    Abstract: An antenna is described including strip conductor circuitry for interconnecting a plurality of patch radiator elements to a common feed. The strip conductor circuitry includes a plurality of four port quadrature couplers having an isolation port. The antenna further includes a plurality of radio frequency terminating loads and a technique for capacitively coupling one of the plurality of radio frequency terminating loads to the isolation port of a corresponding one of the plurality of four port quadrature couplers of the strip conductor circuitry. With such an arrangement, a least expensive antenna is provided which can survive a high temperature environment.
    Type: Grant
    Filed: August 24, 1993
    Date of Patent: April 4, 1995
    Assignee: Raytheon Company
    Inventors: Norbert Sa, Joseph S. Pleva, James B. Conant, Steven A. Upson, Joseph Simoneau, Eugene Gelshteyn
  • Patent number: 5402032
    Abstract: A method for bonding thermally-mismatched elements of a traveling wave tube employs a metallic plate of undulating character. The plate is located at the region of the interface between tube elements formed of materials of materially-differing thermal character such as the ceramic termination piece and an adjacent sever pole piece of copper. Through either a brazing or a sintering process, pluralities of bonds are formed at points of tangency between the plate and the two elements of differing thermal expansion coefficients. As a result, a good heat flow path, accompanied by a more stable r.f. interface, is formed between the materials that is not subject to fracture as are prior art diffusion bonds.
    Type: Grant
    Filed: October 29, 1992
    Date of Patent: March 28, 1995
    Assignee: Litton Systems, Inc.
    Inventors: Curtis G. Allen, David H. Perrone, David M. Rossi
  • Patent number: 5396198
    Abstract: A power source wiring supplies power to individual electronic circuits constituting an electronic circuit device. Load circuits are connected to the power source wiring within the range of an arrival time of a voltage noise occurring in the power source wiring in a time of about a half of a pulse width of a noise current at the time of the operation of the electronic circuit. Each of these load circuits includes a series circuit of a resistance and a capacitance.
    Type: Grant
    Filed: September 9, 1993
    Date of Patent: March 7, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamashita, Hiroyuki Itoh, Keiichirou Nakanishi, Tatsuya Saitoh, Tohru Kobayashi, Satoru Isomura
  • Patent number: 5349288
    Abstract: Electrostatic discharge (ESD) sensing apparatus for testing and displaying extremely high frequency discharges. The apparatus incorporates a surface mounted current shunt in the form of a thin foil or film of less than one skin depth thickness at the frequency of interest. This is sandwiched between a coaxial connector base plate and a ground plane mounting plate. The foil or film is symmetrically oriented about the axis of the connector at a central opening in the mounting plate. A discharge path is provided through the opening to the foil and, on the other side, through a small resistor to the central conductor of the coaxial connector which may be connected to a measuring or display apparatus for a complete test system. A calibration unit includes a plurality of sensing devices configured for different cutoff frequencies and levels of discharge pulses.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: September 20, 1994
    Inventors: John S. Miller, Hugh M. Hyatt
  • Patent number: 5321372
    Abstract: In a computer network having a cable for transmission of electrical signals between data terminal equipment and a device used to control and route data in the network, an apparatus for terminating the cable to minimize emissions radiating from the cable and susceptibility of the cable to outside interferences. The cable is comprised of unshielded twisted pairs of wires. Each twisted pair is individually terminated into a matching input impedance. The difference signals being conducted in each twisted pair produces common mode currents which sets up standing waves through the cable. Consequently, at each end of the cable, the common mode of the twisted pairs is terminated into a load having an impedance approximately equal to the common mode impedance of the twisted pairs. These loads effectively dissipate the energy from the standing waves, thereby minimizing emissions. Reciprocally, susceptibility is likewise minimized.
    Type: Grant
    Filed: January 8, 1993
    Date of Patent: June 14, 1994
    Assignee: SynOptics Communications, Inc.
    Inventor: Robert W. Smith