Frequency-Tracked Signal Demodulation for Separate Sideband Measurement
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Solution Overview
Problem
Existing methods for demodulating signals in noisy environments, such as those in material analysis and quantum physics, require multiple signal processing units and cannot separately measure sidebands at specific frequencies, leading to resource inefficiency and limited signal quality.
Innovation Solution
An apparatus comprising a frequency detector, an oscillator, and a mixer, with an arithmetic unit generating a control signal to demodulate the input signal directly at the frequency of interest, using a single demodulation step and requiring fewer signal processing units, allowing for flexible reference frequency generation and separate measurement of sidebands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple lock-in amplifiers or Fourier-transform methods are used for demodulation, then signal quality and sideband measurement capability are improved, but device complexity and resource requirements increase
Solution Approach 1:
The patent combines the frequency tracking function and demodulation function into a single integrated system. The frequency detector tracks the carrier frequency while the arithmetic unit simultaneously generates the appropriate reference frequencies for demodulation, eliminating the need for separate lock-in amplifiers for each sideband measurement.
Solution Approach 2:
The arithmetic unit serves multiple functions: it receives the tracked frequency, calculates both sideband frequencies (carrier ± modulation frequency), generates control signals for oscillators, and enables demodulation at multiple frequencies through a single device, replacing multiple specialized instruments.
2Adaptability or versatility
If multiple lock-in amplifiers are used for wide-band and narrow-band demodulation, then sideband analysis capability is improved, but resource requirements and device complexity increase
Solution Approach 1:
The patent merges wide-band demodulation and narrow-band demodulation capabilities into a single system. The frequency detector provides tracked frequency information that the arithmetic unit uses to generate reference signals for demodulating both sidebands simultaneously, reducing the need for multiple separate demodulation channels.
Solution Approach 2:
The system dynamically adjusts the reference frequencies based on the tracked carrier frequency. The arithmetic unit continuously calculates updated sideband frequencies as the carrier frequency varies, allowing the system to adapt to frequency drift and maintain accurate sideband measurement without requiring multiple fixed-frequency instruments.
3Measurement precision
If conventional demodulation methods are used, then signal recovery is achieved, but separate measurement of sidebands is not possible and resource efficiency is reduced
Solution Approach 1:
The patent segments the demodulation process into distinct frequency components. The arithmetic unit separately calculates the upper sideband frequency (carrier + modulation frequency) and lower sideband frequency (carrier - modulation frequency), enabling independent measurement of each sideband while using a single integrated device.
Solution Approach 2:
The system uses its own frequency detection output to generate the demodulation reference signals. The tracked carrier frequency from the frequency detector is fed into the arithmetic unit, which automatically generates the appropriate control signals for the oscillators, making the system self-sufficient and eliminating external resource requirements.
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 reduces resource requirements, improves signal quality, and enables efficient measurement of sidebands, suitable for both digital and analogue implementations, avoiding drift and matching issues.
Implementation Method 1
a frequency detector for tracking a frequency, in particular a carrier frequency, of the input signal
Implementation Method 2
a mixer for demodulating the input signal with an output signal of the oscillator as reference signal, the output signal of the mixer being the demodulated input signal
Data Source
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AI summary
The invention relates to an apparatus (300; 400; 500; 600) for demodulating an input signal (306; 402; 520), comprising a frequency detector (302; 403; 502.1,..., 502. N; 603) for tracking a frequency (f2; fd1,..., fdN) of the input signal (306; 402; 520), an oscillator (304; 410; 505; 605, 606) and a mixer (305; 408; 507; 608, 609), wherein the input signal (306; 402; 520) and an output signal (307; 409) of the oscillator (304; 410; 505; 605, 606) constitute the incoming signals for the mixer (305; 408; 507; 608, 609) and the output signal of the mixer (305; 408; 507; 608, 609) constitutes the demodulated input signal, wherein an arithmetic unit (303; 404; 504; 604) is arranged downstream of the frequency detector (302; 403; 502.1,..., 502. N; 603) and upstream of the oscillator (304; 410; 505; 605, 606), wherein the tracked frequency (f2; fd1,..., fdN) of the input signal (306; 402; 520) and a predefined second frequency (f1; faux1,..., fauxM) constitute the incoming signals of the arithmetic unit (303; 404; 504; 604) and the arithmetic unit (303; 404; 504; 604) is designed such that it computes a control signal (f3; f4; fo1,..., foP) for the oscillator (304; 410; 505; 605, 606) from the tracked frequency (f2; fd1,..., fdN) of the input signal (306; 402; 520) and the predefined second frequency (f1; faux1,..., fauxM) with the output signal (307; 409) of the oscillator (304; 410; 505; 605, 606) depending on the control signal (f3; f4; fo1,..., foP). The invention furthermore relates to a method for demodulating an input signal (306; 402; 520) with such an apparatus (300; 400; 500; 600).