RF Signal Generator Current Calibration With Imbalance Correction
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Solution Overview
Problem
Conventional RF signal generator calibration techniques are costly in terms of hardware complexity and power consumption, especially at cryogenic temperatures, and are sensitive to intrinsic offsets in measurement circuits, which can impact accuracy.
Innovation Solution
A calibration system that measures signal currents in RF signal generators using a current measurement circuit and a current imbalance correction circuit, which adjusts current levels to correct imbalances between signal paths, reducing hardware complexity and power consumption while operating effectively at low temperatures and minimizing intrinsic offset errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional on-chip calibration instrumentation implementing RF down-conversion receiver is used to measure RF output signals, then calibration accuracy can be achieved, but hardware complexity and area overhead increase significantly
Solution Approach 1:
The patent extracts the measurement function from the RF domain to the baseband domain. Instead of measuring RF output signals with complex RF down-conversion receivers, the system measures baseband signal currents directly using simple current measurement circuits. This extraction eliminates the need for complex RF measurement instrumentation while maintaining calibration accuracy.
Solution Approach 2:
The patent substitutes complex RF measurement systems with simpler electrical measurement systems. By replacing RF down-conversion receivers and spectrum analyzers with direct baseband current measurement circuits, the system achieves the same calibration functionality with dramatically reduced hardware complexity and area overhead.
2Reliability
If conventional calibration systems performing RF measurements are implemented, then calibration functionality is achieved, but power consumption increases significantly
Solution Approach 1:
The measurement function is extracted from the power-consuming RF domain to the low-power baseband domain. By measuring baseband signal currents directly instead of performing RF measurements, the system maintains calibration functionality while dramatically reducing power consumption.
Solution Approach 2:
The patent uses simple, low-cost current measurement circuits instead of expensive, power-hungry RF measurement systems. The baseband current measurement approach provides adequate calibration functionality with minimal power consumption, making it suitable for energy-constrained applications.
3Difficulty of detecting and measuring
If conventional on-chip calibration instrumentation is used, then RF measurement capability is achieved, but area overhead increases significantly
Solution Approach 1:
The measurement capability is extracted from the RF domain to the baseband domain, where simple current measurement circuits can perform the function with minimal chip area. This extraction eliminates the need for large-area RF measurement instrumentation.
Solution Approach 2:
The patent uses a simplified copy of the measurement function implemented at baseband instead of the full RF measurement system. By copying the essential measurement capability to the baseband domain, the system achieves adequate measurement functionality with minimal area overhead.
4Device complexity
If current measurement circuitry is used for calibration, then hardware complexity is reduced, but sensitivity to intrinsic offsets may increase
Solution Approach 1:
The patent implements a feedback mechanism where the measured baseband signal currents are used to adjust the signal paths and eliminate imbalances. This feedback approach compensates for intrinsic offsets in the current measurement circuitry, maintaining measurement accuracy despite the simplicity of the measurement circuits.
Data Source
AI summary
Techniques are provided for calibrating signal currents in a radio frequency signal generator system, such as an arbitrary waveform generator system. A device comprises a current measurement circuit and a current imbalance correction circuit. The current measurement circuit is configured, during a calibration process, to measure a first current in a first signal path of a radio frequency signal generator, and to measure a second current in a second signal path of the radio frequency signal generator. The current imbalance correction circuit is configured to adjust a current level in at least one of the first signal path and the second signal path of the radio frequency signal generator to correct for an imbalance between the measured first current and the measured second current.