Abstract: A method for measuring interference in a cable transmission system includes the step of establishing a spectrum frequency measurement window having start and stop frequencies and an amplitude threshold. Data is acquired over the window representative of the spectral energy of the cable transmission system within the window and the data is compared against the threshold value. If the data falls below the threshold value, indicating the absence of a carrier signal within the window, a display is generated characterizing the interference over the window. Additional measurement windows may be established having different start and stop frequencies and thresholds for measuring different portions of the cable transmission system frequency spectrum.
Abstract: An instrument housing defines a chamber and has a metal shell with an aperture region defining an array of parallel elongated apertures. The shell has an elongated web between each pair of adjacent apertures, and a raised element protrudes from the web. The raised element is spaced apart from each aperture to reveal a portion of the web near each aperture. A resilient, electrically conductive spring element is electrically connected to the web and has a compressible portion extending away from the web, such that a metal plate pressed toward the revealed surface makes electrical contact with the spring and thereby to the shell, and is laterally constrained by the raised element. The raised element may be welded to the web with the spring captured between, or the raised element may be partially sheared to protrude from the web, with an aperture in the spring closely receiving the raised portion with an interference fit.
Type:
Grant
Filed:
June 20, 1997
Date of Patent:
July 27, 1999
Assignee:
Tektronix, Inc.
Inventors:
Tok Doun, James H. McGrath, Jr., Delmer E. Snyder
Abstract: An active avalanche photo-diode, APD, gain control circuit for use in an optical receiver includes a bias generator for varying the bias on a variable gain APD in response to bias control values generated by a controller. The controller receives the output of the optical receiver and determines the system noise of the receiver for the various bias control values. The system noise is compared to a threshold value for establishing the optimum bias for optimum gain of the APD. The gain control circuit is useable in an optical receiver in an optical time domain reflectometer, OTDR, for increasing the dynamic range of the OTDR.
Abstract: A process for measuring the phase jitter of a data signal using a phase demodulator. To perform an accurate and relatively simple measurement of phase jitter, the data signal is supplied to a phase comparator and an auxiliary clock signal derived from a predetermined clock signal is supplied to the phase comparator via a gate circuit and a frequency divider. If the phase difference between the two signals exceeds a predetermined value, a control circuit controls the gate circuit so that the phase of the auxiliary clock signal is modified until the phase difference drops below the predetermined value. The modified auxiliary clock signal is modified again, generating a comparison clock signal which is provided to a phase modulator having an integrator so that the edge of the corresponding pulse of the data signal falls in the middle of the ramp-like output signal of the integrator when the phase jitter is zero.
Abstract: An error correction circuit for an ATM header of an ATM cell uses a sequence of synchronous comparator circuits to generate a correction mask. The sequence of comparators, when used in a processor having a 32-bit bus, provide for near minimum processing delay at an ATM node. The error correction circuit also provides error status flags for an ATM cell processor, allowing for the processor to discard ATM cells with multiple errors.
Abstract: A receiver processor for use in a SONET OC-48 or SDH test or network environment. The processor includes a 16:32 demultiplexer, descrambler, and a cross-connect enabling individual STS-3s in the incoming signal to be routed to selected STS-3s in the outgoing signal. An overhead and data capture function enables overhead and data bytes to be captured from each frame.
Abstract: A system and method for synchronous switching of digital audio data channels while maintaining block alignment between the switched digital audio signals at an output separates status and user bits from audio data and validity bits for each digital audio signal, storing the status and user bits in respective memories for each digital audio data channel. The audio data and validity bits for each digital audio data channel are input via a data first-in, first-out buffer to an audio multiplexer. The status and user bits from the memories for each digital audio data channel are read out by a system clock in synchronization with a system block signal and input to a status/user multiplexer. A selector provides control signals to the multiplexers to select the digital audio data channel to provide to an output transmitter.
Abstract: A high-frequency calibration method and circuit including a dual path step attenuator. A calibration system is provided having a switch between the user signal input and the instrument input and an amplifier between the calibration signal input and the instrument input. The amplifier provides signal conditioning. The output of the amplifier is connected to the instrument input through a switch and a resistor, the resistor isolating the switch from the instrument input so as effectively to prevent degradation of the user input signal. A sense amplifier provides a calibration signal output indicative of the input impedance of the instrument input in response to a known stimulus. The input of the sense amplifier is isolated from the instrument input by a resistor. A current source provides a known stimulus to the instrument input to measure input impedance. A step attenuator is provided having an attenuated path and an unattenuated path.
Abstract: Colored waxes are made by reacting selected nucleophiles, including alcohol containing colorants with an isocyanate are disclosed. A phase change ink is made by blending the colored wax with a clear ink carrier composition. The clear ink carrier composition can be a fatty amide-based material and/or a combination of isocyanate-derived resins in which the order of addition of the isocyanate and the different nucleophiles can tailor the distribution of di-urethane, mixed urethane/urea, and/or di-urea molecules in the final resin product. The colored wax materials are useful as ingredients with phase change ink carrier compositions to make phase change ink jet inks.
Type:
Grant
Filed:
August 8, 1997
Date of Patent:
July 6, 1999
Assignee:
Tektronix, Inc.
Inventors:
Donald R. Titterington, Jeffery H. Banning, Clifford R. King
Abstract: A channel subassembly for a PALC display panel comprises a channel member defining an array of interconnected channels, a cover sheet extending over the channels and sealed to the channel member, whereby the channel member and the cover sheet define a sealed volume, a mixture of an ionizable gas and hydrogen in the sealed volume, and a quantity of an alloy composed of about 33 wt % Zr, about 33 wt % Fe and about 33 wt % V in communication with the sealed volume.
Type:
Grant
Filed:
September 8, 1997
Date of Patent:
June 29, 1999
Assignee:
Tektronix, Inc.
Inventors:
Mark W. Roberson, Michael D. Wagner, Wayne R. Kurowski
Abstract: A latching electrical connector with a body connectable to a receptacle and having a latch mechanism that mechanically engages the receptacle to resist disconnection. A flexible electrical cable extends from the body, and a grip element is connected to the latch mechanism to unlatch the mechanism upon pulling. The grip element is flexibly connected to the latch mechanism so that it may be folded aside to provide a compact arrangement.
Type:
Grant
Filed:
September 19, 1997
Date of Patent:
June 29, 1999
Assignee:
Tektronix, Inc.
Inventors:
Gary W. Reed, William R. Mark, Paul K. Andersen
Abstract: The invention relates to a switching arrangement for connecting and/or separating two sections (7, 8) of an electrical line (3), said arrangement comprising a switching device (10) having contact elements (11, 12) which are connected to said two line sections (7, 8) as well as a plug device (15) having an actuation element (20) and plug contacts (18, 19).For providing a switching arrangement of particularly simple design for connecting and/or separating two sections of an electrical line, the present invention proposes that the contact elements (11, 12) be electrically connected to the actuation reeds of a reed contact (25) and the actuation element (20) be means magnetically influencing said reed contact which will open said reed contact (25) when the plug devide (15) is plugged in.
Abstract: A conductive refractory compound coating for electrodes is sputter resistant, very resistant to oxidation, and easy to apply by way of electrophoresis or screen printing. This structure is further enhanced by the presence of surface particles of electrically nonconductive ceramic material. When the cathode electrode is energized, electrically nonconductive material is penetrated by the electric field, which attracts secondary electrons out of the cathode electrode, thereby increasing the cathode's efficiency as an emitter of secondary electrons. More specifically, cathode electrodes are used in a plasma addressing structure. The coating is formed by approximately 5 nm particles, each comprised of a fused matrix of conductive and nonconductive particles co-deposited with frit particles by either electrophoresis or "silk" screening. The coating is subsequently baked to fuse the frit and bond the electrophoretically deposited particles to the electrodes.
Type:
Grant
Filed:
July 31, 1997
Date of Patent:
June 29, 1999
Assignee:
Tektronix, Inc.
Inventors:
John S. Moore, William W. Stein, Donald E. Kephart
Abstract: An electrical connector with a female portion defining a bore having an aperture, and a male portion having an elongated member sized to be received in the bore. The female portion has a first flexible contact and an electrically isolated second rigid contact. The male portion has a first flexible contact and an electrically isolated second rigid contact. The connector may be a banana connector with a barrel spring providing conventional contact, and a separate contact at the tip of the male portion.
Abstract: A solid ink stick supply system and related method for delivering solid ink sticks to an ink jet print head reservoir is disclosed. The supply system includes a housing with a keyed plate that guides the ink sticks into the proper loading position in a supply channel. A pusher rod in the supply channel transfers an ink stick onto an endless belt for delivery to the print head reservoir. A push device on the endless belt engages and delivers the ink stick to the print head reservoir. A second ink stick is transferred from the supply channel to the endless belt and is retained on the belt by a stop device. A method for efficiently loading ink sticks into the supply system is also provided.
Type:
Grant
Filed:
September 5, 1996
Date of Patent:
June 29, 1999
Assignee:
Tektronix, Inc.
Inventors:
H. Erwin Grellmann, John B. Gilbert, Robert C. Tidrick, Randy C. Karambelas, William B. Weaver, James B. Jensen, Dale R. Peterson
Abstract: A channel substrate assembly for a plasma addressed liquid crystal display device is made from a channel substrate formed with channels in a first main surface thereof, by attaching a cover sheet to the channel substrate with a first main surface of the cover sheet in confronting relationship with the first main surface of the channel substrate. The cover sheet is then thinned from its second main surface.
Type:
Grant
Filed:
May 15, 1997
Date of Patent:
June 29, 1999
Assignee:
Tektronix, Inc.
Inventors:
Kevin J. Ilcisin, Thomas S. Buzak, Paul C. Martin
Abstract: A process for fabricating the channel substrate of a plasma-addressed electro-optic display device comprising a layer of electro-optic material, data electrodes coupled to the electro-optic layer and adapted to receive data voltages for activating portions of the electro-optic layer, and a plurality of plasma channels extending generally transverse to the data electrodes for selectively switching on said electro-optic portions and closed off by a thin dielectric sheet, typically a thin glass sheet. The channel substrate is fabricated using anodic bonding to attach the thin glass sheet to an etched or walled preferably glass substrate containing the channels. This reduces stresses in the thin glass sheet. Reduced stress allows post processing of the thin sheet, particularly further etching to reduce its thickness.
Type:
Grant
Filed:
February 6, 1995
Date of Patent:
June 22, 1999
Assignees:
Philips Electronics North America Corporation, Tektronix, Inc.
Inventors:
Babar Ali Khan, Jacob Bruinink, Adrianus Leonardus Josephus Burgmans, Henri Roger Jules Richard Van Helleputte, Petrus Franciscus Gerardus Bongaerts, Karel Elbert Kuijk, Thomas Stanley Buzak, Kevin John Ilcisin, Paul Christopher Martin