Frequency Conversion Circuit Calibration for LO Leakage Suppression
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Solution Overview
Problem
Frequency conversion circuits face challenges in suppressing local oscillator (LO) leakage, which causes distortion in output signals and fails to comply with FCC spurious emission requirements, often requiring additional circuitry that increases power consumption and chip area, and may introduce further parasitic signals.
Innovation Solution
A frequency conversion circuit with first and second actuators that adjust basis vectors associated with differential outputs and impedances to offset LO leakage signals, reducing the need for additional circuitry by calibrating and compensating for LO leakage basis vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional circuitry (e.g., additional mixers or complex mixer architectures) is used to mitigate LO distortion, then LO leakage suppression is improved, but chip area and power consumption increase
Solution Approach 1:
The patent changes the electrical parameters (impedance values, basis vectors) of existing circuit components through calibration actuators to achieve LO leakage suppression. By adjusting the impedance of commutating devices and the basis vector of the transconductance stage, the circuit achieves distortion cancellation without adding physical circuitry, thus resolving the contradiction between reliability improvement and chip area reduction.
2Reliability
If additional circuitry (e.g., additional mixers or complex mixer architectures) is used to mitigate LO distortion, then LO leakage suppression is improved, but power consumption increases
Solution Approach 1:
The patent uses calibration actuators to dynamically adjust electrical parameters of existing components rather than powering additional active circuitry. The actuators modify impedance and basis vector parameters to achieve distortion cancellation, consuming minimal power compared to running additional mixers or signal processing circuits, thus resolving the power consumption contradiction.
3Productivity
If traditional frequency conversion circuits use LO input signals, then frequency conversion is enabled, but LO leakage causes distortion in output signal
Solution Approach 1:
The patent converts the harmful LO leakage signal into a useful calibration reference. By measuring the actual LO leakage present in the circuit and using it to drive the calibration actuators, the system generates compensating signals that cancel the distortion. This transforms the harmful leakage into a beneficial feedback mechanism for achieving distortion-free operation.
Solution Approach 2:
The patent implements a feedback mechanism where the LO leakage signal is measured by a detector and used to control calibration actuators that adjust circuit parameters. This closed-loop system continuously monitors and corrects LO distortion, enabling the circuit to maintain frequency conversion capability while actively suppressing the harmful leakage effects.
Data Source
AI summary
A processor may calibrate a first actuator electrically coupled to a transconductance stage of the frequency conversion circuit. The transconductance stage may be configured to receive a differential signal input. Calibrating a first actuator may adjust a first basis vector associated with a differential direct current (DC) output of the transconductance stage. A processor may calibrate a second actuator electrically coupled to receive the differential current output of the transconductance stage and electrically coupled to a set of commutating devices of the frequency conversion circuit. The commutating devices may be configured to receive differential LO inputs. Calibrating a second actuator may adjust a second basis vector associated with a differential impedance of the set of commutating devices. A processor may offset responsive to adjusting the first basis vector and the second basis vector, the first leakage basis vector and second leakage basis vector of the LO leakage signal.