Transmitter Oscillator Calibration for Pulling Effect
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Solution Overview
Problem
Existing signal transmitter devices with multiple transmitters suffer from the pulling effect, which causes phase errors due to RF signal coupling, leading to increased bandwidth requirements and design complexity, and can introduce unnecessary phase noise when calibration mechanisms are used in the phase locked loop.
Innovation Solution
A signal transmitter device with a first transmitter and a second oscillator circuitry, where calibration signals are generated to reduce the pulling effect on both the first and second oscillating signals, using a calibration circuitry that detects the power of output signals to produce coefficients for in-phase and quadrature data signals, thereby eliminating phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a calibration mechanism is placed after the mixer to eliminate the pulling effect, then the phase errors can be corrected, but the bandwidth required for the calibration mechanism increases, resulting in increased cost and design complexity
Solution Approach 1:
The patent applies preliminary action by performing calibration before the mixing operation. The calibration signals are generated and processed through the oscillator and signal processing circuitry beforehand, allowing the pulling effect to be characterized and compensated in advance. This prevents the need for high-bandwidth post-mixing calibration mechanisms, thereby reducing device complexity while maintaining phase error correction capability.
2Measurement precision
If a calibration circuit that eliminates the pulling effect is disposed in the phase locked loop, then the phase errors can be corrected, but unnecessary phase noise is introduced, reducing the overall performance of the transmitter
Solution Approach 1:
The patent extracts the calibration function from the phase locked loop, placing it instead in a separate signal processing path. By taking out the calibration circuitry from the PLL, the design achieves phase error correction without introducing the phase noise that would result from modifying the PLL's oscillating signal. This separation allows independent optimization of each function.
3Adaptability or versatility
If multiple transmitters are equipped in an electronic device, then multiple channel transmission capability is improved, but the pulling effect causes phase errors due to RF signal coupling between transmitters
Solution Approach 1:
The patent introduces calibration signals as an intermediary mechanism to mediate the interaction between multiple transmitters. These calibration signals are injected into the signal processing path to characterize and compensate for the coupling effects between adjacent transmitters. By using this intermediary calibration approach, the system can maintain phase accuracy across multiple channels without requiring physical isolation or complex shielding between transmitters.
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 performance of multiple transmitters by simultaneously eliminating errors caused by the pulling effect, enhancing the performance of signal transmitter devices for multiple channel transmission applications.
Implementation Method 1
The signal processing circuitry mixes a plurality of calibration signals according to the first oscillating signal to transmit a first output signal
Implementation Method 2
The calibration circuitry detects a power of the first output signal to generate a plurality of coefficients
Data Source
AI summary
A transmitter device includes a transmitter including a first oscillator circuitry, a signal processing circuitry, and a calibration circuitry, and a second oscillator circuitry. The first oscillator circuitry is configured to output a first oscillating signal. The signal processing circuitry is configured to mix calibration signals according to the first oscillating signal, in order to emit a first output signal. The calibration circuitry is configured to detect a power of the first output signal to generate coefficients, and generate the calibration signals according to the coefficients, an in-phase data signal, and a quadrature data signal. The second oscillator circuitry is disposed adjacent to the transmitter, and is configured to output a second oscillating signal. The calibration signals are configured to reduce a pulling generated by both of the first output signal and the second oscillating signal to the first oscillator circuitry.