Christopher D Silva

US Patent:

7321641, Jan 22, 2008

Filed:

Jun 3, 2004

Appl. No.:

10/860232

Inventors:

Andrew Alfred Moulthrop - Los Angeles CA, US
Michael Steven Muha - Torrance CA, US
Christopher Patrick Silva - Rancho Palos Verdes CA, US

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H03D 3/22

US Classification:

375332

Abstract:

A communications system reduces downconverter inaccuracies in time-domain measurements or samples of received microwave communications I and Q complex signals by converting received signal to baseband taking measurements or samples of the I and Q waveforms at differing phase shifts of a demodulating carrier signal for a local oscillator or carrier tracking loop used during downconversion so that I and Q imbalances may be detected and removed by lowpass equivalent averaging for improved characterization of downconverters or for improved signal reception. In the preferred form, the phase shifts are 0 and π/2 for a conventional measurement, and then at θ, and θ+π/2, with θ=π/4+mπ/2 for an integer m for the second measurement where I and Q imbalances and baseband nonlinearities are indicated by differences between the two measured or sampled signals, where θ provides for optimum error detection for reducing the errors by averaging the measurements.

US Patent:

7583759, Sep 1, 2009

Filed:

Jan 18, 2008

Appl. No.:

12/016638

Inventors:

Andrew Alfred Moulthrop - Los Angeles CA, US
Michael Steven Muha - Torrance CA, US
Christopher Patrick Silva - Rancho Palos Verdes CA, US

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H04L 27/22

US Classification:

375332

Abstract:

A communications system reduces downconverter inaccuracies in time-domain measurements or samples of received microwave communications I and Q complex signals by converting received signal to baseband taking measurements or samples of the I and Q waveforms at differing phase shifts of a demodulating carrier signal for a local oscillator or carrier tracking loop used during downconversion so that I and Q imbalances may be detected and removed by lowpass equivalent averaging for improved characterization of downconverters or for improved signal reception. In the preferred form, the phase shifts are 0 and π/2 for a conventional measurement, and then at θ, and θ+π/2, with θ=π/4+mπ/2 for an integer m for the second measurement where I and Q imbalances and baseband nonlinearities are indicated by differences between the two measured or sampled signals, where θ provides for optimum error detection for reducing the errors by averaging the measurements.

US Patent:

61278998, Oct 3, 2000

Filed:

May 29, 1999

Appl. No.:

9/322891

Inventors:

Christopher Patrick Silva - Rancho Palos Verdes CA
Albert Miebach Young - Whittier CA

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H03B 2900

US Classification:

331 78

Abstract:

A high frequency anharmonic oscillator provides a broad band chaotic oscillation with a noise-like spectra. The oscillator output signal is suitable for modulation by data providing for improved secure communication. The chaotic oscillator is based upon a forced second order Duffing equation that is tolerant of delay in the feedback path for high frequency operation.

US Patent:

60646942, May 16, 2000

Filed:

Sep 30, 1997

Appl. No.:

8/940578

Inventors:

Christopher Joseph Clark - Hermosa Beach CA
Andrew Alfred Moulthrop - Culver City CA
Michael Steven Muha - Torrance CA
Christopher Patrick Silva - Lomita CA

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H04B 346
H04B 1700
H04Q 120

US Classification:

375224

Abstract:

A three-pair measurement method determines the amplitude and phase transmission response of frequency translating devices including a device under test and two test devices using a vector network analyzer and a controller where one of the devices has reciprocal frequency response characteristics. The characterization of single sideband and double sideband devices such as mixers, is preferably performed by combining data from analyzer two-port swept measurements. The measurement method provides a low-pass equivalent transmission response of the devices.

US Patent:

60410779, Mar 21, 2000

Filed:

May 4, 1999

Appl. No.:

9/305263

Inventors:

Christopher Joseph Clark - Hermosa Beach CA
Andrew Alfred Moulthrop - Culver City CA
Michael Steven Muha - Torrance CA
Christopher Patrick Silva - Lomita CA

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H04B 346

US Classification:

375224

Abstract:

A three-pair measurement method determines the amplitude and phase transmission response of frequency translating devices including a device under test and two test devices using a vector network analyzer and a controller where one of the devices has reciprocal frequency response characteristics. The characterization of single sideband and double sideband devices such as mixers, is preferably performed by combining data from analyzer two-port swept measurements. The measurement method provides a low-pass equivalent transmission response of the devices.

US Patent:

59370068, Aug 10, 1999

Filed:

May 28, 1997

Appl. No.:

8/865276

Inventors:

Christopher Joseph Clark - Hermosa Beach CA
Andrew Alfred Moulthrop - Culver City CA
Michael Steven Muha - Torrance CA
Christopher Patrick Silva - Lomita CA

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H04B 346
H04B 1700
H04Q 120

US Classification:

375224

Abstract:

A three-pair measurement method determines the amplitude and phase transmission response of frequency translating devices including a device under test and two test devices using a vector network analyzer and a controller where one of the devices has reciprocal frequency response characteristics. The characterization of single sideband and double sideband devices such as mixers, is preferably performed by combining data from analyzer two-port swept measurements. The measurement method provides a low-pass equivalent transmission response of the devices.

US Patent:

62116630, Apr 3, 2001

Filed:

May 28, 1999

Appl. No.:

9/322270

Inventors:

Andrew Alfred Moulthrop - Los Angeles CA
Michael Steven Muha - Torrance CA
Christopher Joseph Clark - Hermosa Beach CA
Christopher Patrick Silva - Rancho Palos Verdes CA

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

G01R 2316
G01S 740

US Classification:

324 7623

Abstract:

A time-domain baseband measurement method measures modulated microwave signals typically used in communication systems by converting microwave signals to baseband before measurement for improved accuracy compared to direct measurement at the microwave frequency. A downconverting receiver is first characterized using a prior characterization method and then the modulated microwave signal is applied to the downconverting receiver and the response of the downconverting receiver is removed to provide an accurate characterization of the modulated microwave signal. Such an accurate measurement of the modulated microwave signal can be used for communications system performance verification as well as for characterizing communications devices and systems. One particular application is the measurement of input/output characteristics of nonlinear power amplifiers using such modulated microwave signals.