Oscillator Signal Power Detection Using Injection Locking Thresholds
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Solution Overview
Problem
Conventional signal power detection methods are inaccurate due to un-ideal factors in circuits, especially when detecting low-power signals like carrier leakage, and suffer from DC errors in analog-to-digital conversion.
Innovation Solution
An apparatus and method that utilize injection locking characteristics to determine signal power by switching between two frequencies based on the oscillating circuit's state, avoiding inaccuracies by using frequency as a reference instead of voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a power detector or mixer-type detector is used to measure signal power, then the signal power can be converted to a voltage value for detection, but the detection accuracy deteriorates for low-power signals due to un-ideal circuit factors
Solution Approach 1:
The patent replaces the conventional voltage-based detection system with a frequency-based detection system using an oscillator. Instead of measuring signal power through voltage conversion which is affected by circuit imperfections, the system uses an oscillator whose frequency changes in response to the to-be-detected signal power, enabling accurate detection of low-power signals through frequency measurement rather than voltage measurement.
Solution Approach 2:
The patent changes the detection parameter from voltage to frequency. The oscillator's oscillation frequency is changed according to the power of the to-be-detected signal, allowing the system to detect signal power levels by measuring frequency changes rather than voltage changes, thereby avoiding the limitations of voltage-based detection for low-power signals.
2Object-generated harmful factors
If DC voltages are added to calibration signals to reduce carrier leakage power, then the carrier leakage can be suppressed, but DC errors in ADC conversion create further calibration errors
Solution Approach 1:
The patent replaces the voltage-based calibration system with a frequency-based calibration system. Instead of adjusting DC voltages to calibration signals which introduces ADC conversion errors, the system uses an oscillator whose frequency naturally responds to the signal power level, eliminating the need for DC voltage adjustments and the associated ADC conversion errors.
Solution Approach 2:
The oscillator serves as an intermediary between the to-be-detected signal and the detection system. Rather than directly measuring voltage and converting it through an ADC, the oscillator translates signal power information into frequency information, which can be detected more accurately without suffering from ADC DC offset errors.
3Measurement precision
If expensive, accurate power detectors are used to detect low-power signals, then detection accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex voltage-based detection circuits with a simpler frequency-based detection system using an oscillator. The oscillator inherently provides frequency information that correlates with signal power, eliminating the need for complex power detector circuits and ADC conversions, thereby reducing both device complexity and cost while maintaining detection accuracy for low-power signals.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of signal power detection across various fields, including carrier leakage calibration in signal transmitters, by effectively distinguishing between signal powers above and below a threshold without being affected by circuit imperfections.
Implementation Method 1
the present invention adopts characteristics of injection locking occurs when an oscillating circuit is interfered by an interference signal having large power
Data Source
AI summary
An apparatus for determining signal power comprise an oscillating circuit and a determining circuit. The oscillating circuit generates an oscillating signal. When a to-be-detected signal has signal power greater than a threshold, the oscillating signal has a first frequency; when the signal power is smaller than the threshold, the oscillating signal has a second frequency. The determining circuit determines whether the oscillating signal has either the first frequency or the second frequency, and generates a determination result accordingly.