FMCW Radar Signal Generator Reducing Settling Phase
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Solution Overview
Problem
Current radar signal generators for short-range frequency modulated continuous waveform (FMCW) radars face challenges in achieving high signal-to-noise ratio (SNR) and reducing electrical consumption, particularly in minimizing the settling phase and maximizing the frequency band while maintaining fine spatial resolution.
Innovation Solution
A generator that produces a frequency modulated radar signal with a periodic signal having a linearly varying instantaneous frequency over a wide frequency band, utilizing a device that generates a sinusoidal signal with controlled amplitude to optimize the modulation envelope, allowing the oscillator to operate only during specific periods, thereby reducing power consumption and enhancing SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the generator operates continuously to maintain fine spatial resolution and high frequency band coverage, then the signal-to-noise ratio and measurement precision are improved, but the electrical consumption increases
Solution Approach 1:
The generator operates in periodic bursts rather than continuously. Each period T includes an active phase where the generator produces frequency-modulated signals for a duration Tramp, followed by an inactive phase where power consumption is minimized. This periodic operation allows the radar to accumulate measurements over multiple periods while reducing overall energy consumption compared to continuous operation.
Solution Approach 2:
The generator is pre-configured with stored energy or pre-charged capacitors that enable rapid signal generation at the start of each active period. This preliminary preparation allows the generator to immediately produce high-quality signals without requiring continuous power supply, thus maintaining measurement precision during the active phase while enabling energy savings during inactive phases.
2Measurement precision
If the frequency band B is widened to improve spatial resolution, then the separating power between targets is improved, but the duration of the ramp phase Tramp must be reduced which increases the duty cycle and power consumption
Solution Approach 1:
The system dynamically adjusts the ramp duration Tramp and frequency band B parameters based on operational requirements. By optimizing the relationship between frequency sweep range and sweep time, the system achieves wide frequency band coverage (improving spatial resolution) while maintaining efficient duty cycle operation. The parameter α (frequency sweep rate) is specifically tuned to balance these competing requirements.
3Productivity
If the settling phase Ttransitory is reduced to improve productivity, then the measurement efficiency is improved, but the signal stability and reliability during the ramp phase may deteriorate
Solution Approach 1:
The system implements a rapid settling phase that quickly transitions the generator from inactive to active state. By optimizing the startup circuitry and using pre-biased operating points, the settling time Ttransitory is minimized, allowing the generator to reach stable operation quickly. This enables longer effective measurement windows Tramp within each period T, improving overall productivity while maintaining signal reliability through careful circuit design.
Data Source
AI summary
A generator of a frequency modulated radar signal includes a generator of a periodic signal frequency modulated over a part Tramp of a period T, corresponding to a square signal of which the frequency varies linearly in a first frequency band Bin of central frequency fin; an oscillator generating a sinusoidal signal of frequency fc>fin and included in a second frequency band Bamp>Bin and corresponding to the linear variation of the frequency of the radar signal; and means coupled to an electrical supply input of the oscillator such that they generate a voltage for supplying the oscillator at the frequency of the frequency modulated periodic signal.