FMCW Radar Level Gauge Lock-State Control for Low-Power Sensing
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Solution Overview
Problem
Conventional frequency modulated continuous wave (FMCW) radar level gauge systems are power hungry, making them less suitable for applications with limited power sources, such as field devices or wireless devices powered by batteries or solar cells.
Innovation Solution
The radar level gauge system incorporates PLL circuitry with frequency modifying and amplifying circuitry that only consumes energy and modifies the output signal when the PLL is in a locked state, reducing energy waste and minimizing RF-energy emission outside permitted frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If FMCW radar level gauge systems continuously operate frequency modifying circuitry and amplifying circuitry to ensure immediate signal transmission, then measurement readiness and response time are improved, but energy consumption increases significantly
Solution Approach 1:
The patent applies periodic action by controlling the frequency modifying circuitry and amplifying circuitry to operate only during specific periods when the PLL circuitry is in a locked state, rather than continuously. The circuitry is activated periodically based on the PLL lock status, enabling measurement functionality when needed while conserving energy during initialization or idle periods.
Solution Approach 2:
The patent implements dynamics by making the operation of frequency modifying circuitry and amplifying circuitry conditional and adaptive based on the PLL circuitry's lock state. The system dynamically adjusts its operational state - activating these circuitry components when the PLL is locked and disabling them when not locked - allowing the system to respond to changing conditions and optimize between readiness and energy consumption.
2Speed
If frequency modifying circuitry operates during PLL initialization phase, then signal transmission is immediate, but RF energy may be emitted outside permitted frequency bands
Solution Approach 1:
The patent applies preliminary action by requiring the PLL circuitry to complete its initialization and achieve a locked state before the frequency modifying circuitry is activated. This preliminary step ensures that the correct operating frequency is established and stabilized before any RF energy transmission occurs, preventing frequency band interference while maintaining eventual signal transmission readiness.
Solution Approach 2:
The patent implements feedback by using the PLL lock status signal to control the operation of frequency modifying circuitry. The system continuously monitors the PLL lock state and uses this feedback information to determine when it is safe to activate the frequency modifying circuitry, ensuring that signal transmission only occurs when the PLL has stabilized at the correct frequency.
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 energy consumption and allows for more efficient filling level determination in power-constrained applications by optimizing energy use based on the PLL lock state, enhancing the system's power efficiency.
Implementation Method 1
PLL circuitry for generating an output signal, the PLL circuitry being configured to indicate a lock state of the PLL circuitry
Implementation Method 2
frequency modifying circuitry connected to the PLL circuitry for receiving the output signal and for increasing a frequency of the output signal to form the transmit signal
Implementation Method 3
The transmitted signal is reflected by the surface of the contents in the tank (or by any other impedance transition) and an echo signal, which has been delayed a certain time, is returned to the gauge
Implementation Method 4
The echo signal is mixed with the transmitted signal to generate a mixer signal, having a frequency equal to the frequency change of the transmitted signal that has taken place during the time delay
Data Source
AI summary
The present invention relates to a radar level gauge system comprising PLL circuitry for generating an output signal. The PLL circuitry is configured to indicate a lock state of the PLL circuitry; and signal modifying circuitry is connected to the PLL circuitry for receiving the output signal and for modifying at least one property of the output signal for forming the transmit signal. The signal modifying circuitry is arranged and configured to receive a PLL status signal indicative of the lock state of the PLL circuitry, and to modify the at least one property of the output signal in response to the PLL status signal indicating that the PLL circuitry is in a locked state.