Amplifier phase distortion correction based on amplitude distortion measurement
This application discloses correction circuitry for correcting a phase distortion in an amplification circuit by measuring an amplitude distortion and controlling a phase shifting component based upon the measured amplitude distortion. In one embodiment, a first amplitude distortion sensor is coupled to a first node of an amplification circuit, and a first phase shifter is coupled to a second node of the amplification circuit. Additionally, a first control circuit is coupled to the first amplitude sensor and to the first phase shifter. The first control circuit is configured to correlate a first amplitude distortion measured by the first amplitude distortion sensor to a first inferred phase distortion, and to generate a first phase correction signal based upon the first inferred phase distortion, and is configured to send the first phase correction signal towards the first phase shifter.
1. Circuitry comprising:
amplification circuitry comprising a first transistor and a second transistor stacked with the first transistor, wherein the first transistor includes a gate, a drain, and a source, and the amplification circuitry is configured to receive an input signal at an input node and provide an amplified output signal at an output node;
an amplitude distortion sensor coupled to the drain of the first transistor and configured to measure amplitude distortion at the drain of the first transistor to provide an amplitude distortion measurement signal;
a phase shifter coupled to the gate of the first transistor and configured to adjust a phase of the input signal based on a phase correction signal; and
control circuitry coupled between the amplitude distortion sensor and the phase shifter and configured to receive the amplitude distortion measurement signal and provide the phase correction signal based on the amplitude distortion measurement signal.
2. The circuitry of claim 1 , further comprising:
an intermediate amplitude distortion sensor coupled to a first intermediate node of the amplification circuitry and configured to measure amplitude distortion in a first intermediate signal to provide an intermediate amplitude distortion measurement signal; and
an intermediate phase shifter coupled to a second intermediate node of the amplification circuitry and configured to adjust a phase of a second intermediate signal based on an intermediate phase correction signal, wherein the control circuitry is coupled between the intermediate amplitude distortion sensor and the intermediate phase shifter and configured to receive the intermediate amplitude distortion measurement signal and provide the intermediate phase correction signal.
3. The circuitry of claim 2 , wherein:
the amplitude distortion sensor and the phase shifter form at least a portion of a first feedback loop; and
the intermediate amplitude distortion sensor and the intermediate phase shifter form at least a portion of a second feedback loop.
4. The circuitry of claim 2 , wherein:
the amplitude distortion sensor and the phase shifter form at least a portion of a first feedback loop; and
the intermediate amplitude distortion sensor and the intermediate phase shifter form at least a portion of a first feed forward loop.
5. The circuitry of claim 2 , wherein:
the amplitude distortion sensor and the phase shifter form at least a portion of a first feed forward loop; and
the intermediate amplitude distortion sensor and the intermediate phase shifter form at least a portion of a second feed forward loop.
6. Circuitry comprising:
amplification circuitry configured to receive an input signal at an input node and provide an amplified output signal at an output node, the amplification circuitry comprising:
a first transistor having a gate, a drain, and a source; and
a second transistor having a gate, a drain, and a source coupled to the drain of the first transistor; and
an amplitude distortion sensor coupled to the output node of the amplification circuitry and configured to measure amplitude distortion in the amplified output signal to provide an amplitude distortion measurement signal,
a phase shifter coupled between the input node and the amplitude distortion sensor and configured to adjust a phase of the input signal based on the amplitude distortion measurement signal.
7. The circuitry of claim 6 , wherein:
the amplitude distortion sensor is coupled to the drain of the first transistor; and
the phase shifter is coupled to the gate of the first transistor.
8. The circuitry of claim 7 , further comprising:
an intermediate phase shifter coupled to the gate of the second transistor.
9. The circuitry of claim 8 , further comprising:
an intermediate amplitude distortion sensor coupled to the source of the second transistor.
10. The circuitry of claim 9 , further comprising:
an additional intermediate phase shifter coupled to the drain of the second transistor.
11. The circuitry of claim 10 , wherein the amplitude distortion sensor is a true transconductance saturation detector.