Harmonic Filters for Polar Modulators
AssigneeEridan Communications, Inc.
InventorsFran Kostelac, Ante Brizic, Dubravko Babic
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Abstract
A modulated RF carrier produced at the output of the polar transmitter's switch-mode power amplifier (SMPA) is conveyed to an output filter network comprising a harmonic low-pass filter (LPF) connected in parallel with an absorptive high-pass filter (HPF). Together the harmonic LPF and absorptive HPF pass the fundamental component of the modulated RF carrier to the polar transmitter's load while also absorbing higher harmonic components that would otherwise be undesirably reflected back toward the output of the SMPA.
Claims56
A polar transmitter, comprising:
- a polar modulator having a switch-mode power amplifier (SMPA) configured to produce a modulated radio frequency (RF) carrier;
- and
- an output filter network coupled to an output of the polar modulator, the output filter network including a passive low-pass filter (LPF) having a first filter order connected in parallel with an absorptive high-pass filter (HPF) having a second filter order,
- wherein the first filter order and second filter order are different.
A polar transmitter, comprising:
- a polar modulator having a switch-mode power amplifier (SMPA) configured to produce a modulated radio frequency (RF) carrier;
- and
- a passive output filter network coupled to an output of said polar modulator, said passive output filter network comprising a tunable low-pass filter (LPF) connected in parallel with an absorptive high-pass filter (HPF).
A polar transmitter, comprising:
- a polar modulator having a switch-mode power amplifier (SMPA) configured to produce a modulated radio frequency (RF) carrier;
- and
- a passive output filter network coupled to an output of said polar modulator, said passive output filter network comprising a low-pass filter (LPF) connected in parallel with a tunable absorptive high-pass filter (HPF).
A method of filtering a modulated radio frequency (RF) carrier signal produced by a polar modulator, comprising:
- passing a fundamental component of the modulated RF carrier to a load using a passive low-pass filter (LPF) having a first filter order;
- and
- absorbing a harmonic component of the modulated RF carrier signal reflected from the passive LPF toward an output of the polar modulator using an absorptive high-pass filter (HPF) having a second filter order different from the first filter order.
A method of filtering a modulated radio frequency (RF) carrier signal produced by a polar modulator, comprising:
- passing a fundamental component of the modulated RF carrier to a load using a low-pass filter (LPF) having a first filter order;
- and
- absorbing a harmonic component of the modulated RF carrier signal reflected from the LPF toward an output of the polar modulator using an absorptive high-pass filter (HPF),
- wherein the LPF has a corner frequency different from a corner frequency of the absorptive HPF.
Dependencies are inferred from the claim text.