Microwave Backhaul Resonator Phase Noise Correction
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Solution Overview
Problem
Conventional microwave backhaul systems face limitations in achieving low phase noise due to high phase noise at higher frequencies and temperature instability, which affects the reliability and accuracy of microwave communications.
Innovation Solution
The implementation of a split-architecture microwave backhaul transceiver with a surface acoustic wave (SAW) or bulk acoustic wave (BAW) resonator-based oscillator and an auxiliary phase-locked loop (PLL) for error signal generation and phase correction, along with digital feedback circuitry for predistortion coefficients determination, to mitigate phase noise and temperature drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional microwave backhaul systems operate at higher frequencies, then data transmission capacity is improved, but phase noise increases
Solution Approach 1:
The system divides the frequency generation into multiple components: a low-phase-noise reference oscillator and a frequency synthesizer that generates higher frequency signals by multiplying the reference. This segmentation allows the system to achieve high data transmission capacity at higher frequencies while maintaining low phase noise through the reference oscillator's stable reference signal.
Solution Approach 2:
The patent implements feedback mechanisms through phase-locked loops (PLLs) that continuously monitor and adjust the frequency of the local oscillator to maintain synchronization with the reference signal. This feedback control ensures that phase noise is suppressed while allowing the system to operate at higher frequencies for increased data capacity.
2Productivity
If conventional microwave backhaul systems operate at higher frequencies, then data transmission capacity is improved, but temperature instability increases
Solution Approach 1:
The system employs temperature compensation techniques by adjusting the frequency of the local oscillator based on temperature sensor feedback. The frequency synthesizer modifies its operating parameters in response to temperature changes, maintaining stable performance across varying temperature conditions while operating at higher frequencies for increased data capacity.
Solution Approach 2:
Temperature sensors provide continuous feedback on the thermal state of the system, and the frequency synthesizer adjusts its output frequency accordingly to compensate for temperature-induced drift. This feedback mechanism ensures temperature stability is maintained even as the system operates at higher frequencies to maximize data transmission capacity.
3Productivity
If frequency synthesizer is used to generate higher frequency signals, then data transmission capacity is improved, but phase noise increases
Solution Approach 1:
The frequency generation is segmented into a low-phase-noise reference oscillator that provides a stable foundation and a frequency synthesizer that multiplies this reference to generate higher frequencies. This segmentation allows the system to achieve high data transmission capacity through frequency multiplication while the reference oscillator maintains low phase noise characteristics.
Solution Approach 2:
The phase-locked loop acts as an intermediary between the low-phase-noise reference oscillator and the frequency synthesizer, filtering out phase noise while allowing frequency multiplication. This intermediary mechanism enables the system to achieve high data capacity through frequency synthesis while maintaining the low phase noise benefits of the reference oscillator.
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 significantly reduces phase noise and temperature instability, ensuring reliable and accurate microwave communications by compensating for frequency and phase drifts, thereby enhancing the overall performance of microwave backhaul systems.
Implementation Method 1
a first resonant circuit (180) operable to generate a first signal (181) characterized by a first amount of phase noise and a first amount of temperature stability
Implementation Method 2
a first resonant circuit (180) operable to generate a first signal (181) characterized by a first amount of phase noise and a first amount of temperature stability
Implementation Method 3
an auxiliary phase-locked loop (PLL) for error signal generation and phase correction
Implementation Method 4
phase error compensation circuitry operable to adjust the phase of a data signal (409) based on the phase error signal
Data Source
AI summary
A system comprises a microwave backhaul outdoor unit having a first resonant circuit, phase error determination circuitry, and phase error compensation circuitry. The first resonant circuit is operable to generate a first signal characterized by a first amount of phase noise and a first amount of temperature stability. The phase error determination circuitry is operable to generate a phase error signal indicative of phase error between the first signal and a second signal, wherein the second signal is characterized by a second amount of phase noise that is greater than the first amount of phase noise, and the second signal is characterized by a second amount of temperature instability that is less than the first amount of temperature instability. The phase error compensation circuitry is operable to adjust the phase of a data signal based on the phase error signal, the adjustment resulting in a phase compensated signal.