| CPC H03H 9/54 (2013.01) [H01P 5/19 (2013.01); H03H 9/66 (2013.01)] | 42 Claims |
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1. An apparatus comprising:
a filter circuit comprising:
a first filter port;
a second filter port;
a first signal manipulator circuit comprising a first port, a second port, and a third port coupled to the first filter port, the first signal manipulator circuit configured to:
split an input signal into multiple split signals;
shift a phase of one or more split signals of the multiple split signals to produce at least one phase-shifted split signal and at least one split signal; and
provide the at least one phase-shifted split signal and the at least one split signal to the first port and the second port;
a first lattice filter coupled to the first port of the first signal manipulator circuit;
a second lattice filter coupled to the second port of the first signal manipulator circuit; and
a second signal manipulator circuit comprising a first port coupled to the first lattice filter, a second port coupled to the second lattice filter, and a third port coupled to the second filter port, the second signal manipulator circuit configured to:
accept multiple filtered signals from the first lattice filter and the second lattice filter;
shift a phase of one or more filtered signals of the multiple filtered signals to produce at least one phase-shifted filtered signal and at least one filtered signal; and
combine the at least one phase-shifted filtered signal and the at least one filtered signal into an output signal at the third port of the second signal manipulator circuit, wherein the first signal manipulator circuit and the second signal manipulator circuit are jointly configured to:
at least attenuate at the output signal a third-order harmonic or a second-order harmonic that is generated based on the input signal by at least one of the first lattice filter or the second lattice filter.
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