Power amplifier system and mobile phone terminal using same
View Patent ↗A power amplifier system includes a first power amplifier, a second harmonic generator, a phase shifter, and first and second adders. The first power amplifier amplifies a primary input signal. The second harmonic generator outputs a second harmonic by using a split part (signal) of the primary input signal as an input. The phase shifter adjusts a phase of the second harmonic. The first adder sums together a split signal of the primary input signal and an output of the phase shifter, thereby to produce an output. The second power amplifier uses the output of the first adder as an input. The second adder sums together an output of the first amplifier and an output of the second power amplifier, thereby to produce an output.
1. A power amplifier system, comprising:
a first power amplifier for amplifying a primary input signal;
a second harmonic generator for outputting a second harmonic by using a split part signal of the primary input signal as an input;
a phase shifter for adjusting a phase of the second harmonic;
a first adder for summing together a split part signal of the primary input signal and an output of the phase shifter, thereby to produce an output;
a second power amplifier that uses the output of the first adder as an input; and
a second adder for summing together an output of the first amplifier and an output of the second power amplifier, thereby to produce an output.
2. A power amplifier system as claimed in claim 1 , wherein the first power amplifier is biased to any one of class A and class AB, and the second power amplifier is biased to the class C.
3. A power amplifier system as claimed in claim 1 , wherein the second harmonic generator uses a source-grounded field effect transistor biased to the class C, wherein a bandpass filter for passing the second harmonic is coupled to a drain terminal of the field effect transistor.
4. A power amplifier system as claimed in claim 1 , wherein a frequency conversion mixer is used as the second harmonic generator.
5. A mobile phone terminal, comprising a power amplifier system, wherein the power amplifier system includes:
a first power amplifier for amplifying a primary input signal;
a second harmonic generator for outputting a second harmonic by using a split part signal of the primary input signal as an input;
a phase shifter for adjusting a phase of the second harmonic;
a first adder for summing together a split part signal of the primary input signal and an output of the phase shifter, thereby to produce an output;
a second power amplifier that uses the output of the first adder as an input; and
a second adder for summing together an output of the first amplifier and an output of the second power amplifier, thereby to produce an output.
6. The mobile phone terminal as claimed in claim 5 , wherein the first power amplifier is biased to any one of class A and class AB, and the second power amplifier is biased to the class C.
7. The mobile phone terminal as claimed in claim 5 , wherein the second harmonic generator uses a source-grounded field effect transistor biased to the class C, wherein a bandpass filter for passing the second harmonic is coupled to a drain terminal of the field effect transistor.
8. The mobile phone terminal as claimed in claim 5 , wherein a frequency conversion mixer is used as the second harmonic generator.