Super-Regenerative Receiver Frequency Correction During Quench Phase
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Solution Overview
Problem
The resonant frequency of a voltage-controlled oscillator (VCO) drifts during the quench phase due to changes in bias current, affecting the accuracy of radiofrequency signal reception in super-regenerative receivers.
Innovation Solution
A calibration method using a Voltage Control Oscillator bias current dependent varactor, where pre-calibrated voltages are stored in a lookup table to correct frequency drift by adjusting the varactor's capacitance, ensuring the oscillator frequency remains within 0.99 to 1.01 of its reference value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the bias current is increased to start the oscillation during quench phase, then the oscillation signal amplitude rises rapidly, but the resonant frequency drifts due to skin effect and capacitance variations
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the relationship between bias current and frequency drift at multiple operating points before actual operation. The measured drift characteristics are stored in a lookup table, allowing the system to compensate for frequency variations proactively rather than reactively during the quench phase oscillation cycle.
Solution Approach 2:
The patent implements feedback by using a voltage-controlled oscillator with a varactor whose capacitance is adjusted based on feedback from the bias current level. The system continuously monitors the operating point and adjusts the varactor capacitance to counteract frequency drift, maintaining stable resonant frequency despite current variations during quench phase.
2Measurement precision
If the inductor operates with negative resistance to enhance quality factor, then selectivity improves, but the equivalent parallel inductor value changes due to current variations
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the varactor capacitance parameter in response to bias current variations. This compensates for the changes in equivalent parallel inductor value caused by negative resistance effects, maintaining consistent resonant frequency and selectivity across different operating conditions during quench phase.
3Stability of the object's composition
If multiple calibration points are used to improve frequency correction accuracy, then frequency stability improves, but device complexity increases due to lookup table storage requirements
Solution Approach 1:
The patent applies partial action by using a finite number of discrete calibration points (e.g., 3-5 points) across the operating range rather than continuous calibration. This provides sufficient frequency correction accuracy for practical applications while keeping the lookup table size manageable and device complexity acceptable, representing an optimal trade-off between correction precision and implementation complexity.
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 method effectively stabilizes the oscillator frequency during the quench phase, enhancing the selectivity and accuracy of radiofrequency signal reception by reducing frequency variations, thereby improving the overall performance of super-regenerative receivers.
Implementation Method 1
A correction of this frequency drift during the quench phase can be done, advantageously, by using a Voltage Control Oscillator bias current dependent varactor
Implementation Method 2
the inductor circuit equivalent model gets a serial resistor, which represents rolled into one its metal resistance, the skin effect and the Eddy currents losses within the substrate
Implementation Method 3
the inductor circuit equivalent model gets a serial resistor, which represents rolled into one its metal resistance, the skin effect and the Eddy currents losses within the substrate
Implementation Method 4
According to the presence or not of a RF signal at the resonance frequency, or very close, of the oscillator and according to the amplitude of the RF signal, the oscillator starts-up more or less rapidly
Data Source
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AI summary
The present invention concerns a correction method (500) for a super-regenerative receiver (100) being configured to resonate at at least one oscillator resonant frequency reference value (111) and comprising at least one control stage (130), at least one varactor (140), at least one reference system (150) and, at least one oscillator (110). Said correction method (500) comprising at least one setup (510) of at least one reference signal value (158) by said at least one reference system (150), at least one comparison (560) of at least one oscillator frequency actual value (112) of said at least one oscillator (110) with said at least one reference signal value (158) by said at least one reference system (150) and at least one adjustment (570) of at least one gain of said at least one control stage (130).