Transceiver Wake-Up Receiver Clock Calibration
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Solution Overview
Problem
Current sensor networks face challenges in achieving ultra-low power consumption and long battery life due to inaccuracies in real-time counters, which limit the duty cycle of RF transceivers, leading to increased power consumption and reduced battery life, especially when using external high-precision oscillators that are costly and power-hungry.
Innovation Solution
A transceiver device with a wake-up receiver mechanism that receives calibration signals periodically to adjust the real-time clock, allowing for synchronization with reduced power consumption and cost, achieving accuracy comparable to a crystal oscillator without the need for an external oscillator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high precision external temperature compensated crystal oscillator is used to improve real-time-counter accuracy, then the frequency error is reduced, but the power consumption increases significantly (10 μA compared to on-chip relaxation oscillator)
Solution Approach 1:
The patent introduces a calibration signal as an intermediary element that carries timing reference information from a master node. This calibration signal allows slave nodes to synchronize their real-time counters without requiring expensive external crystal oscillators, thus resolving the contradiction between accuracy and power consumption.
Solution Approach 2:
The system implements a feedback mechanism where slave nodes receive calibration signals containing timing information and adjust their real-time counter frequency accordingly. This feedback loop enables continuous synchronization without requiring high-precision local oscillators, achieving both accuracy and low power consumption.
2Use of energy by moving object
If the duty cycle is reduced to minimize average power consumption, then power consumption decreases, but the real-time-counter accuracy must be improved to maintain synchronization
Solution Approach 1:
The calibration signal mechanism provides continuous feedback to slave nodes, allowing them to maintain accurate timing even with extremely low duty cycles. The feedback ensures that frequency drift and offset are corrected periodically, enabling duty cycles as low as 10^-5 while maintaining synchronization.
Solution Approach 2:
The master node performs preliminary action by generating and transmitting calibration signals that contain pre-calculated timing information. This allows slave nodes to synchronize without needing high-precision local oscillators, enabling them to remain in sleep mode for extended periods.
3Measurement precision
If a crystal oscillator is used to calibrate the real-time-counter, then the frequency offset is calibrated, but noise, temperature or supply voltage induced variation are not addressed
Solution Approach 1:
The calibration signal contains comprehensive timing information that enables slave nodes to correct not only frequency offset but also drift caused by noise, temperature, and supply voltage variations. The continuous feedback mechanism ensures all these error sources are compensated, improving overall synchronization reliability.
Data Source
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AI summary
The present invention relates to a transceiver device comprising a real time clock (20) arranged for providing a clock signal and a receiving section comprising - a main receiver (40) arranged for receiving communication signals, - a wake-up receiver (10) arranged for receiving a calibration signal comprising clock timing information containing a time stamp and for adjusting said real time clock based on said clock timing information.