Robert Carleton Powell
Engineers at Walker Ave, Gaithersburg, MD

4621226, Nov 4, 1986

May 23, 1984

6/613340

Robert C. Powell - Gaithersburg MD

Weinschel Engineering Co., Inc. - Gaithersburg MD

G01R 2706, G01R 2704

324 58B

Apparatus and method for determining an input electrical characteristic of a device under test by power-related measurements made by the device under test, wherein the input characteristic to be determined is related to the input impedance of the device under test. Specifically, the input impedance, the reflection coefficient, or the standing wave ratio of the input to the device under test is determined by a plurality of power, voltage, or current measurements made by a meter or sensor in the device under test. The plurality of measurements are made when the device under test is in a network including (a) a first leg having a first fixed impedance and a selectively variable impedance forming a series and (b) a second leg having a second fixed impedance and the device under test in series, an electrical input of constant amplitude being applied to the network with power being split symmetrically between the two legs. Three measurements made by the device under test when the variable impedance is selected to be in open circuit, a short circuit, and an impedance matched to the second fixed impedance are combined to provide the value of the sought input characteristic.

4628256, Dec 9, 1986

Jun 27, 1983

6/508090

Robert Powell - Gaithersburg MD

Weinschel Engineering Co., Inc. - Gaithersburg MD

G01R 2104, G01R 1924, G01R 1918

324 95

An improved meter for measuring RF power. The RF power is applied to thermocouple means which transforms the RF power into a low level d. c. signal which then passes through a chopper stage that is driven by a clamped sinusoidal input. The output of the chopper stage includes periodic pulses with a prescribed pulse spacing: pulse duration ratio, the pulses being passed through a band-pass filter at a harmonic of the chopper drive signal. The filtered signal, which is also amplified, undergoes synchronous detection with a tri-level square-wave signal which is centered in phase relative to the amplified, filtered signal when the two signals are in phase. The power meter measurements adjusted for zero drift and calibration drift by a microprocessor; based on zero measurements and calibration measurements made before and after an RF measurement is made. Measurements are stored and processed digitally to enhance accuracy. Signals through the meter can be at relatively high frequencies to reduce 1/f noise; spiking at the chopper stage and synchronous detector is virtually eliminated; and the tri-level square-wave permits greater tolerance to phase shift, all of which reduce output error.

4240050, Dec 16, 1980

Jun 29, 1979

6/053343

Robert C. Powell - Gaithersburg MD

Weinschel Engineering Co., Inc. - Gaithersburg MD

H01P 102

333 33

In order to cancel unwanted reflected waves in a waveguide system, two micrometer-driven stub tuners are inserted in a waveguide bend. A first tuner is inserted through the outer bend wall to extend axially along one leg of the bend and includes a dielectric rod having a reflecting slug at its tip. Axial movement of the rod permits the variable position of the slug to vary the phase of the wave which it reflects. The second tuner includes a metal rod, which enters the waveguide transversely from the inner wall of the bend, diametrically across from the entrance of the dielectric rod, and permits adjustment of the magnitude of the wave which it reflects.

4977366, Dec 11, 1990

Oct 7, 1988

7/260501

Robert C. Powell - Gaithersburg MD

Lucas Weinschel Inc. - Gaithersburg MD

G01R 2104

324 95

The present invention relates to devices utilized for measurement of high frequency and microwave power. More specifically, the present invention relates to apparatus and technique for measurement of power including the construction and configuration of a power-sensing probe for detection of the power level of a high frequency or microwave signal.