Transceiver Circuit Ranging With Crystal Offset Compensation
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Solution Overview
Problem
Existing distance measurement techniques between transceivers are inaccurate due to crystal offset, particularly in phase-based ranging methods used in Bluetooth Low Energy (BLE) and IoT applications.
Innovation Solution
A transceiver circuit design that includes an antenna, receiver RF chain, transmitter RF chain, and controller to calculate distance estimates by exchanging initiation and reflection signals at specified frequencies, compensating for crystal offset through I/Q measurements and phase-based methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-based ranging techniques are used to determine distance between transceivers, then distance measurement capability is provided, but measurement precision deteriorates due to crystal offset
Solution Approach 1:
The system performs preliminary I/Q measurements and phase difference calculations before final distance determination. By measuring the phase difference between transmitted and received signals and calculating the corresponding distance estimate in advance, the system can later compensate for crystal offset effects using the relationship: distance = (phase difference / 360) * wavelength, thereby improving measurement precision while maintaining reliability
Solution Approach 2:
The system uses feedback from I/Q measurements and phase difference observations to correct distance calculations. By continuously monitoring the phase difference and comparing it with expected values, the system can identify and compensate for crystal offset effects, improving both measurement precision and reliability through iterative correction
2Measurement precision
If single-frequency transmission is used for distance measurement, then device complexity is reduced, but measurement precision deteriorates due to inability to compensate for crystal offset
Solution Approach 1:
The system employs periodic signal exchanges at specified frequencies, where each exchange consists of initiation signals and reflection signals transmitted and received at defined time intervals. This periodic structure allows the system to accumulate multiple phase difference measurements that can be averaged or processed together, improving measurement precision without requiring complex simultaneous multi-frequency operations
Solution Approach 2:
The system performs preliminary I/Q measurements and phase difference calculations during the signal exchange process. By measuring the phase difference between transmitted initiation signals and received reflection signals in advance, the system can calculate distance estimates and compensate for crystal offset effects before final determination, thereby improving precision while maintaining manageable complexity through structured measurement sequences
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
Improves the accuracy of distance measurements by mitigating errors caused by crystal offset, enhancing precision in phase-based ranging techniques.
Implementation Method 1
a receiver RF chain configured to receive a receiver RF signal from the antenna
Implementation Method 2
a transmitter RF chain configured to transmit a transmitter RF signal to the antenna
Implementation Method 3
calculate a second distance estimate between the antenna and the other transceiver circuit, and to determine a range estimate between the antenna and the other transceiver circuit based on the first distance estimate and the second distance estimate
Implementation Method 4
compensating for crystal offset through I/Q measurements and phase-based methods
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
A transceiver circuit is disclosed. The transceiver circuit includes an antenna, a receiver RF chain configured to receive a receiver RF signal from the antenna, a transmitter RF chain configured to transmit a transmitter RF signal to the antenna, and a controller configured to cause the receiver RF chain to receive a first distance estimate between the antenna and another transceiver circuit, to calculate a second distance estimate between the antenna and the other transceiver circuit, and to determine a range estimate between the antenna and the other transceiver circuit based on the first distance estimate and the second distance estimate.