OPTIMIZED UPLINK EFFICIENCIES FOR TRANSMISSION OF SATELLITE DATA

• US 20080129374A1
• Filed: 10/11/2007
• Published: 06/05/2008
• Est. Priority Date: 10/17/2006
• Status: Active Grant

• Current Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Santoru, Joseph, Maitra, Shamik, Chen, Ernest C., Lin, Tung-Sheng, Lai, Dennis, Zhou, Guangcai, Comeaux, Cecilia
• Granted Patent: US 7,535,292 B2
• Time in Patent Office: Days
• US Class Current: 330/2
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H04B 17/0085 using test signal generators
• CPC Class Codes: H04B 17/15 Performance testing

Abstract

Systems and methods for characterizing amplifiers. A system for characterizing an amplifier in accordance with the present invention comprises a Gaussian signal source for generating a signal in the frequency domain, a notch filter, coupled to the Gaussian Noise source, wherein the notch filter has a notch at a specified frequency and a frequency bandwidth, the frequency bandwidth encompassing the specified frequency, an Inverse Fast Fourier Transform device, coupled to an output of the notch filter, a normalization device, coupled to the Inverse Fast Fourier Transform device, an amplifier under test, coupled to the normalization device, for amplifying the signal generated by the Gaussian signal source, and a measurement device, coupled to an output of the amplifier, for measuring a power output of the amplifier in the frequency bandwidth and a noise output at the specified notch frequency, and for calculating the ratio between the power output and the noise output.

Claims

1. A system for characterizing an amplifier, comprising:

a Gaussian signal source for generating a signal in the frequency domain;

a notch filter, coupled to the Gaussian Noise source, wherein the notch filter has a notch at a specified frequency and a frequency bandwidth, the frequency bandwidth encompassing the specified frequency;

an Inverse Fast Fourier Transform device, coupled to an output of the notch filter;

a normalization device, coupled to the Inverse Fast Fourier Transform device;

an amplifier under test, coupled to the normalization device, for amplifying the signal generated by the Gaussian signal source;

a measurement device, coupled to an output of the amplifier, for measuring a power output of the amplifier in the frequency bandwidth and a noise output at the specified notch frequency, and for calculating the ratio between the power output and the noise output.

2. The system of claim 1, wherein the amplifier is used in a satellite communications system.

3. The system of claim 2, wherein the satellite communications system is a direct broadcast system for television signals.

4. A method for characterizing an amplifier, comprising:

supplying a Gaussian signal;

notch filtering the Gaussian signal, wherein the notch filter has a notch at a specified frequency and a frequency bandwidth, the frequency bandwidth encompassing the specified frequency;

applying an Inverse Fast Fourier Transform to the notch filtered Gaussian signal to transform the Gaussian signal into a time domain signal;

normalizing the time domain signal;

applying the normalized time domain signal to an input of the amplifier;

measuring a power output of the amplifier in the frequency bandwidth and a noise output at the specified frequency; and

calculating the ratio between the power output and the noise output.

5. The method of claim 4, wherein the amplifier is used in a satellite communications system.

6. The method of claim 5, wherein the satellite communications system is a direct broadcast system for television signals.