Nonlinear amplifier operating point determination system and method
First Claim
1. A system for measuring the operating point of a nonlinear amplifier, comprisinga transponder which comprises:
- a test signal generator capable of generating an input test signal;
an input communication channel capable of carrying a communication carrier signal;
a summing circuit connected to combine said input test signal and said communication carrier signal to produce a summed signal; and
a nonlinear amplifier connected to receive said summed signal, and to generate an amplified summed signal; and
an analyzer for establishing the small signal gain of said amplifier, comprising;
a receiver for receiving said amplified summed signal; and
a power sensor connected to sense the test signal component of the amplified summed signal'"'"'s power as an indication of the amplifier'"'"'s operating point.
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Accused Products
Abstract
The operating point of a nonlinear amplifier is determined by injecting a known test signal into the communication channel and measuring the gain of the amplified test signal. Each amplifier is characterized by a small signal gain curve that relates the gain of the test signal to the input power of the amplifier. In the amplifier'"'"'s nonlinear range, the gain uniquely determines the input power level of the amplifier, which in turn uniquely determines the operating point of the amplifier. The invention is particularly applicable to satellite transponder architectures that employ "burst" transmission schemes and phased array antennas.
44 Citations
17 Claims
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1. A system for measuring the operating point of a nonlinear amplifier, comprising
a transponder which comprises: -
a test signal generator capable of generating an input test signal; an input communication channel capable of carrying a communication carrier signal; a summing circuit connected to combine said input test signal and said communication carrier signal to produce a summed signal; and a nonlinear amplifier connected to receive said summed signal, and to generate an amplified summed signal; and an analyzer for establishing the small signal gain of said amplifier, comprising; a receiver for receiving said amplified summed signal; and a power sensor connected to sense the test signal component of the amplified summed signal'"'"'s power as an indication of the amplifier'"'"'s operating point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for determining a nonlinear amplifier'"'"'s power transfer characteristic, comprising:
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generating a channel input signal; generating a known test signal; combining the test signal with the channel input signal to drive the nonlinear amplifier at one time, and driving the amplifier with the test signal by itself at another time; measuring the gain imparted by the amplifier to the test signal; measuring the gain imparted by the amplifier to the test signal when combined with the channel input signal; comparing the gain imparted by the amplifier to the test signal when the amplifier is driven in its linear range by said test signal alone and in its nonlinear range by the combined test and channel input signals to provide an indication of the amplifier'"'"'s power transfer characteristic. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification