Direct Frequency Multiplication Millimeter Wave Spectroscopy
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Solution Overview
Problem
Conventional Fourier transform millimeter wave spectroscopy faces challenges in maintaining phase reproducibility and synchronizing signal generation with external events due to the reliance on fixed frequency sources and phase coherence issues between excitation and frequency reference sources.
Innovation Solution
The method involves direct multiplication of microwave pulses using a free-running signal generator and frequency multiplier circuit to generate millimeter-wave pulses, allowing for phase-coherent excitation and detection without the need for external frequency references or local oscillators, enabling synchronization with asynchronous events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frequency mixers and local oscillators are used to generate millimeter-wave signals, then frequency generation capability is improved, but device complexity and phase coherence challenges increase
Solution Approach 1:
The patent removes frequency mixers and local oscillators from the system, extracting only the essential frequency multiplication function. A single local oscillator generates microwave signals that are directly frequency-multiplied to millimeter-wave frequencies, eliminating the complex frequency mixing architecture while maintaining frequency generation capability.
Solution Approach 2:
The patent combines the local oscillator and frequency generation functions into a single integrated system. The local oscillator simultaneously provides the reference frequency and generates the excitation signal, which is then frequency-multiplied to produce both the excitation and detection signals, merging multiple functions into one coherent architecture.
2Reliability
If fixed frequency sources are used to maintain phase reproducibility, then phase coherence is improved, but adaptability to asynchronous events deteriorates
Solution Approach 1:
The patent implements a dynamic triggering system where the fixed-frequency local oscillator runs continuously but signal acquisition is triggered asynchronously by external events. The phase coherence is maintained relative to the oscillator's fixed frequency, while the triggering mechanism adapts to arbitrary external events, combining stability with flexibility.
Solution Approach 2:
The local oscillator operates in advance continuously at a fixed frequency, establishing a stable phase reference before any triggering event occurs. When an asynchronous event triggers acquisition, the system immediately captures signals that are phase-coherent with the pre-established oscillator, enabling both phase reproducibility and asynchronous adaptability.
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 simplifies the system, reduces costs, and enhances sensitivity by allowing immediate triggering and phase-coherent signal averaging, improving signal-to-noise ratio without the complexity of frequency mixing and local oscillators.
Implementation Method 1
frequency-multiplying the at least one pulse to generate at least one frequency-multiplied pulse
Implementation Method 2
rotational spectroscopy is a powerful structural tool in physical chemistry. For example, the relationship between the molecular structure and the rotational transition frequencies can be used for structure determination of gas phase samples
Data Source
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AI summary
Methods and apparatuses for direct multiplication Fourier transform millimeter wave spectroscopy are disclosed herein. A sample method includes generating at least one pulse of microwave electromagnetic energy. The sample method also includes frequency-multiplying the pulse(s) to generate at least one frequency-multiplied pulse and filtering at least one spurious harmonic of the frequency-multiplied pulse to generate at least one filtered pulse. The spurious harmonic is generated by frequency-multiplying the pulse. The method also includes exciting a sample using the filtered pulse. The method further includes detecting an emission from the sample. The emission is elicited at least in part by the filtered pulse.