Pulse Radar Mixer Switching for Low-Power High-SNR Sampling
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Solution Overview
Problem
Existing electrical circuits for radar systems face challenges in achieving a balance between high gain, low current consumption, and robustness against phase noise, particularly in sequential sampling pulse radar (SSPR) applications, where they often compromise on signal-to-noise ratio and complexity.
Innovation Solution
An electrical circuit that switches a mixer and downstream circuit on or off based on a DC signal component, allowing for adaptive power consumption and synchronization with input signals, eliminating the need for a separate clock signal and enhancing robustness against phase noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a self-biased mixer is used to reduce current consumption, then current consumption is reduced, but the gain is limited to approximately 6 dB and signal-to-noise ratio improvement is only 10 dB
Solution Approach 1:
The patent applies dynamic biasing by controlling the mixer with a local oscillator signal that modulates the bias current. The mixer transistor operates in a dynamically changing bias state rather than a fixed state, allowing it to achieve higher gain when the LO signal is present while maintaining low average current consumption. The bias current is dynamically adjusted based on the LO signal amplitude, enabling the mixer to transition between low-power and high-gain modes.
Solution Approach 2:
The patent changes the bias current parameter dynamically by using the LO signal to control the biasing of the mixer transistor. By varying the bias current in response to the LO signal, the mixer achieves improved gain and signal-to-noise ratio while maintaining low average power consumption. The bias point is not fixed but is instead modulated to optimize performance during active signal processing.
2Reliability
If continuous operation is used to maintain signal processing capability, then signal processing is continuous, but current consumption increases
Solution Approach 1:
The patent implements periodic switching of the mixer and downstream circuit based on the presence of the local oscillator signal. The circuits are activated only during periods when the LO signal is present and switched off during intervals when no LO signal is detected. This periodic operation maintains signal processing capability during active periods while dramatically reducing average current consumption during inactive periods, achieving a balance between reliability and energy efficiency.
3Ease of operation
If a separate clock signal is used for synchronization, then synchronization is achieved, but the system becomes dependent on a clock signal susceptible to phase noise
Solution Approach 1:
The patent implements self-synchronization by using the local oscillator signal itself to control the switching of the mixer and downstream circuits. The LO signal serves dual purposes: it provides the mixing function and simultaneously acts as the synchronization trigger. This eliminates the need for a separate clock signal and makes the system immune to phase noise issues associated with external clock sources, as the LO signal is inherently phase-coherent with the transmitted signal.
4Reliability
If the downstream circuit is always active to process mixer output, then signal processing capability is maintained, but current consumption increases
Solution Approach 1:
The patent implements periodic switching of the downstream circuit based on the LO signal presence. The downstream circuit, including amplifiers and integrators, is activated only during periods when the LO signal is present and switched off during inactive periods. This ensures that signal processing capability is maintained when needed while minimizing average current consumption by keeping the downstream circuit in a low-power state during intervals when no processing is required.
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
The solution achieves a high signal-to-noise ratio and low current consumption, ensuring efficient processing and integration of input signals over long periods with improved robustness to phase noise, particularly in pulse radar systems.
Implementation Method 1
a mixer which is configured to receive and mix the first and second input signals in order to generate a mixer output signal
Implementation Method 2
The electrical circuit also has a downstream circuit which is configured to switch on or off based on the DC signal component of the mixer output signal
Data Source
AI summary
An electrical circuit for providing an output signal based on a first input signal and a second input signal has: a mixer which is configured to receive and mix the first and second input signals in order to generate a mixer output signal and to switch on or off based on the first input signal, wherein a DC signal component of the mixer output signal depends on whether the mixer is switched on or off; and a downstream circuit which is configured to switch on or off based on the DC signal component of the mixer output signal and to provide the output signal based on the mixer output signal.