Theodore Austin Nelson

US Patent:

6720828, Apr 13, 2004

Filed:

Nov 21, 2001

Appl. No.:

09/992058

Inventors:

Theodore G. Nelson - Portland OR
Michael P. Khaw - Portland OR
Daniel G. Knierim - Beaverton OR
John F. Stoops - Portland OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H03G 320

US Classification:

330144, 330284, 333 81 R

Abstract:

A high impedance attenuator for use in a test and measurement instrument employs compensation to adjust the low frequency attenuation to match the high frequency attenuation exhibited by the attenuator, rather than attempting to adjust the high frequency attenuation exhibited by the attenuator. In an alternate embodiment of the invention, compensation to adjust low frequency attenuation is employed in a feedback loop and an opposite compensation is applied in a parallel attenuation stage to stabilize the input resistance. In yet another embodiment of the invention, compensation to adjust low frequency attenuation is employed by means of an R-C time constant of an additional R-C circuit in a feed forward loop. This additional time constant is matched to the R-C time constant of the input R-C network. The input resistance of the attenuator is not changed.

US Patent:

8350499, Jan 8, 2013

Filed:

Jan 4, 2010

Appl. No.:

12/652016

Inventors:

Theodore G. Nelson - Portland OR, US

Assignee:

C. Crane Company, Inc. - Fortuna CA

International Classification:

H05B 37/02

US Classification:

315307, 315291, 315297, 315209 R, 315294

Abstract:

A power conditioning circuit in a light bulb efficiently converts an Alternating Current (AC) input voltage into Direct Current (DC) power for operating LEDs in the light bulb. The power conditioning circuit discharges capacitors when a voltage level of the input voltage drops below a given voltage necessary to operate the LEDs. The capacitors are then recharged when the input voltage is high enough to power the LED. The capacitors are configured to operate as voltage dividers while being charged thus reducing a peak voltage level of the output voltage used for powering the LEDs. The reduced output voltage reduces the overall amount of energy used by the light bulb and reduces the amount of heat radiated by the light bulb.

US Patent:

62188240, Apr 17, 2001

Filed:

May 7, 1998

Appl. No.:

9/074444

Inventors:

H. Wayne Oldstead - Beaverton OR
Frank Goovaerts - Banks OR
Theodore G. Nelson - Portland OR
Michael R. Engbretson - Beaverton OR
J. Steve Lyford - Portland OR
Jerry L. Wrisley - Beaverton OR
Charles L. Saxe - Portland OR
James L. Williamson - Aloha OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

G01R 1508
G01R 100

US Classification:

324115

Abstract:

A simplified user interface for an electronic test and measurement device comprises an arrangement of a segmented LCD device and a plurality of keys used to implement a softkey system, in combination with a single AMPs input connector and a rotary selector having only a single position for each basic kind of parameter to be measured. The segmented LCD device includes, at each location adjacent to a key, a plurality of segments representing a vertically-arranged list of functions to be controlled. In one embodiment of the invention, the housing of the electronic test and measurement device is fabricated to have finger-like projections overlaying a portion of the LCD screen for creating the appearance of the continuation of displayed LCD softkey separation lines.

US Patent:

60980958, Aug 1, 2000

Filed:

Feb 26, 1998

Appl. No.:

9/031091

Inventors:

Theodore G. Nelson - Portland OR
James R. Brooks - Beaverton OR
Warren Woo - Portland OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

G06F 1336

US Classification:

709208

Abstract:

A method by which a microprocessor based handheld multi-meter, or other handheld electronic instrument, can communicate with a computer or other microprocessor based device through the measurement input jacks of the handheld multi-meter. A handheld meter, thus equipped, can receive control or calibration data from, and provide test or calibration data to, a host computer or microprocessor based accessory or other instrument. To enable this capability, the handheld meter employs dual-signal, single-axis jacks, for example split banana jacks, for one or more of its signal and ground receptacles. The handheld meter and the computer, or another microprocessor based instrument or accessory device that the meter is to communicate with, are equipped with mutually compatible software and appropriate hardware to support single signal path communication.

US Patent:

46911740, Sep 1, 1987

Filed:

Sep 19, 1986

Appl. No.:

6/909437

Inventors:

Theodore G. Nelson - Beaverton OR
Calvin D. Diller - Hillsboro OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H03F 345

US Classification:

330260

Abstract:

An amplifier includes first and second transistors having emitters connected to a first current source, feedback from the second transistor collector to its base being supplied through a base-emitter path of a first Darlington pair in series with a first diode. A second current source is connected to the first Darlington pair emitter. Third and fourth transistors have emitters connected to a third current source with feedback supplied from the fourth transistor collector to its base through a second Darlington pair and a second diode. The second Darlington pair emitter is connected to a fourth current source and resistively coupled to the first Darlington pair emitter. Constant currents are supplied to the second and fourth transistor collectors and an input voltage across the first and third transistor bases controls allocation of current between the first and second Darlington pair emitter-collector paths to produce a differential output current proportional to the input voltage when both Darlington pairs are on. When the input voltage is highly negative, the first Darlington pair turns off and a biasing circuit reverse biases the first diode to prevent the second transistor from saturating and substantially discharging capacitance at the base of the first Darlington pair. Thus, the first Darlington pair can rapidly turn on when the input voltage is subsequently driven more positive.

US Patent:

45076189, Mar 26, 1985

Filed:

Oct 4, 1982

Appl. No.:

6/432491

Inventors:

Theodore G. Nelson - Beaverton OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H03F 368
H01P 122

US Classification:

330126

Abstract:

A compensation method and apparatus for a roughly compensated RC attenuator using fixed resistors and fixed capacitors. Any difference of the high frequency attenuation ratio from the low frequency of DC attenuation ratio is detected and corrected by using multiplier for increasing or decreasing high frequency components at the output from such RC attenuator, thereby allowing digital or remote compensation of RC attenuator without using variable capacitors.

US Patent:

58314857, Nov 3, 1998

Filed:

Sep 4, 1997

Appl. No.:

8/923712

Inventors:

Theodore G. Nelson - Portland OR
Gary M. Johnson - Hillsboro OR

Assignee:

Tektronix, Inc. - Wilsonville OR

International Classification:

H03L 102

US Classification:

331 47

Abstract:

A method and apparatus for producing a temperature stable frequency at reduced cost. Advantage is taken of an existing, relatively temperature insensitive, low frequency and low cost watch crystal and an existing, high frequency, low cost, but relatively temperature sensitive system clock. A calibration module coupled to the watch crystal and clock calibrates the watch crystal to a reference frequency at a reference temperature and calibrates the clock to the watch crystal at an operating temperature, to relate the clock frequency to the reference frequency at any operating temperature and thereby provide a high precision, relatively temperature insensitive time or frequency base at low cost.

US Patent:

61726303, Jan 9, 2001

Filed:

Aug 18, 1998

Appl. No.:

9/136137

Inventors:

Theodore G. Nelson - Portland OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H03M 300

US Classification:

341143

Abstract:

A delta-sigma modulator includes an integrator which includes an integrating amplifier having an input terminal and an output terminal. A pole of a first single-pole-double-throw (SPDT) switch is coupled to a first electrode of an input capacitor, while a first throw of the first SPDT switch is coupled to an input signal source, and a second throw is coupled to a source of reference potential (ground). A pole of a second SPDT switch is coupled to a second electrode of the capacitor, while a first throw of the second SPDT switch is coupled to the input terminal of the integrating amplifier. A feedback signal generator has an input terminal coupled to the output terminal of the integrating amplifier, and an output terminal directly coupled to a second throw of the second SPDT switch.