Optimized uplink efficiencies for transmission of satellite data
View Patent ↗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.
1. A system for characterizing an amplifier across a frequency bandwidth, comprising:
a signal source for generating a signal in the frequency domain;
a notch filter, coupled to the signal source, the notch filter having a notch at a notch frequency;
an amplifier under test, coupled to the normalization device, for amplifying the signal generated by the 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 notch frequency, and for calculating a ratio between the power output and the noise output.
2. The system of claim 1 , wherein the signal source is a Gaussian source.
3. The system of claim 2 , wherein the Gaussian source is upconverted to an operating frequency of the amplifier.
4. The system of claim 1 , wherein the notch frequency is centered in the frequency bandwidth.
5. The system of claim 4 , wherein the notch has a specified bandwidth.
6. The system of claim 1 , further comprising an Inverse Fast Fourier Transform device, coupled to an output of the notch filter, such that the measurement device calculates the ratio in a time domain.
7. The system of claim 1 , further comprising a normalization device, coupled to the Inverse Fast Fourier Transform device, for normalizing an output of the Inverse Fast Fourier Transform device.
8. The system of claim 1 , wherein the amplifier is used in a satellite communications system.
9. The system of claim 8 , wherein the satellite communications system is a direct broadcast system for television signals.
10. A method for characterizing an amplifier across a frequency bandwidth, comprising:
notch filtering a Gaussian input signal to the amplifier, wherein the notch filtering comprises notching the Gaussian input signal at a specified frequency across the frequency bandwidth;
measuring a power output of the amplifier across the frequency bandwidth and a noise output at the specified frequency; and
calculating the ratio between the power output and the noise output.
11. The method of claim 10 , wherein the specified frequency is centered in the frequency bandwidth.
12. The method of claim 11 , wherein the specified frequency has a specified bandwidth.
13. The method of claim 10 , further comprising transforming the notch filtered Gaussian signal into a time domain signal.
14. The method of claim 13 , further comprising normalizing the time domain signal.
15. The method of claim 10 , wherein the amplifier is used in a satellite communications system.
16. The method of claim 15 , wherein the satellite communications system is a direct broadcast system for television signals.
17. A measurement device for characterizing an amplifier across a frequency bandwidth, comprising:
a Gaussian signal source for generating a signal in the frequency domain, the Gaussian signal source being upconverted to an operating frequency of the amplifier;
a notch filter, coupled to the Gaussian signal source, the notch filter having a notch at a notch frequency; and
a measurement device, coupled to an output of the amplifier, for measuring a power output of the amplifier across the frequency bandwidth and a noise output at the notch frequency, and for calculating a ratio between the power output and the noise output.
18. The measurement device of claim 17 , wherein the power output and the noise output are measured in a time domain.
19. The measurement device of claim 17 , wherein the Gaussian signal source has an adjustable power output.
20. The measurement device of claim 17 , wherein the amplifier is characterized for use in a satellite communications system.