DR. JOHN CARLSON, D.C.
Chiropractic at Greenburg Rd, Portland, OR

6392219, May 21, 2002

Jun 22, 2000

09/603122

David J. McCormick - Portland OR
John E. Carlson - Portland OR

Tektronix, Inc. - Beaverton OR

H01J 4014

250214R, 250226

A reference receiver has a biased, strobed sampling system that is tuned to provide the predominant frequency response of the reference receiver allowing for the removal of the discrete reference receiver filter. The reference receiver has a photodiode optical-to-electrical converter that is configured to effectively utilize the current output of the high impedance source in that the converter is not reverse terminated to the characteristic impedance of a transmission coupled to the electrical output of the converter. The electrical output of the converter is coupled to a sampling circuit that receives biasing voltages and gating strobe pulses for producing an approximate Bessel-Thompson filter response from the sampling circuit. The combination of the unterminated optical-to-electrical converter and the tuned sampling circuit results in a reference receiver having higher gain and narrower reference receiver tolerance limits.

6292052, Sep 18, 2001

Jun 22, 2000

9/602574

John E. Carlson - Portland OR

Tektronix, Inc. - Beaverton OR

H03F 102, G11C 2702

330 9

An output amplifier for a strobed sampling circuit has first and second operational amplifiers coupled to receive the sampled output from the sampling circuit. The operational amplifiers each have a RC circuit having a high ohmic value resistor that is coupled from its inverting input terminal to its output terminal. The non-inverting input terminals receive biasing voltages that are coupled to the sampling circuit. The gating strobes to the sampling circuit produces a DC current through the feedback resistor as a result of strobe pulses being integrated by the RC circuit. Respective electronic switches are coupled in parallel with the RC circuits of the operational amplifiers and are closed at a predetermined time interval after each strobe pulse to discharge the stored charge on the capacitors prior to the next strobe pulse. The output signals from the operational amplifiers are summed in a summing amplifier.

7522661, Apr 21, 2009

Jul 25, 2005

11/189955

Michael A. Nelson - Lake Oswego OR, US
John E. Carlson - Portland OR, US

Tektronix, Inc. - Beaverton OR

H04B 3/46

375224, 375150, 375225, 375226, 375228, 375254, 702 66, 702 69, 702181

A method of producing of a two-dimensional probability density function eye diagram and Bit Error Rate eye arrays generates a two-dimensional PDF array of a correlated waveform record of a data pattern under test which is convolved with a two-dimensional probability density function (PDF) array of the uncorrelated jitter and noise in the data pattern under test. The resulting aggregate two dimensional PDF array of the correlated waveform record pattern with uncorrelated jitter and noise is divided into unit intervals and the unit intervals are summed to generated a two-dimensional PDF eye diagram array. The two-dimensional PDF eye diagram is processed to generate a two-dimensional Bit Error Rate eye array.

4924110, May 8, 1990

Sep 8, 1988

7/241686

John B. Rettig - Portland OR
Jonathan Lueker - Portland OR
John E. Carlson - Portland OR
Stanley P. Kaveckis - Aurora OR
Roy W. Lewallen - Beaverton OR

Tektronix, Inc. - Beaverton OR

H03K 402, H03K 512, H03K 501, H03K 1756

307227

A step generator for producing steps having constant edge parameters while driving varying loads includes a pair of DC coupled low speed diode switches for slowly switching the output load current. A pair of capacitors provide an AC coupled high speed input for rapidly, but temporarily, switching the output load current until the sustaining action of the low speed diode switch has occurred. A pair of resistor divider circuits in each of the low speed diode switches maintains a relatively constant reverse bias voltage across the diodes coupled to the capacitors. The high speed switching threshold is maintained at a relatively constant level which produces an output voltage step with constant edge parameters and no overshoot.

4755742, Jul 5, 1988

Apr 30, 1986

6/858611

Agoston Agoston - Beaverton OR
John B. Rettig - Aloha OR
Stanley P. Kaveckis - Aurora OR
John E. Carlson - Portland OR
Andrew E. Finkbeiner - Beaverton OR

Tektronix, Inc. - Beaverton OR

H03K 1716, H03K 1774

324 58B

A dual channel time domain reflectometer includes a pair of input lines connected at respective nodes to a reference flat current pulse generator and a traveling wave sampling gate, respectively. The sampling gates are actuated by a balanced strobe generator which includes a waveguide coupler for coupling a high amplitude fast rise time pulse to each of the gates simultaneously. Pulses of requisite amplitude and shape are generated by a circuit responsive to a strobe trigger input which drives a step recovery diode.

2013008, Mar 28, 2013

Sep 23, 2011

13/243024

JOHN A. CARLSON - PORTLAND OR, US

TEKTRONIX, INC - BEAVERTON OR

G06F 19/00

702104

Embodiments of the present invention provide enhanced methods of calibrating arbitrary waveform generators using s-parameters, and arbitrary waveform generators calibrated according to those methods. Methods are provided for calibrating a single, non-interleaved channel of an arbitrary waveform generator, calibrating multiple interleaved channels, and calibrating pairs of channels, both interleaved and non-interleaved, to generate differential signals.

4758736, Jul 19, 1988

Mar 28, 1986

6/845289

Agoston Agoston - Beaverton OR
John E. Carlson - Portland OR

Tektronix, Inc. - Beaverton OR

H03K 501, H03K 326

307268

A pulse generator utilizes a pair of current sources acting through a pair of Schottky diode switches to provide load currents in opposite directions through a load resistor to produce an output voltage across the load resistor of magnitude proportional to the difference between the load current magnitudes. The pulse generator output voltage is abruptly driven to zero potential by applying balanced, rapid slewing voltage pulses to the Schottky diode switches, causing the switches to simultaneously divert the load currents from the load resistor. The balanced voltage pulses are developed at the terminals of a step-recovery diode by switching the step-recovery diode from forward to reverse bias state.