Band-Limited Noise Phase Control for Tunable Crest Factor
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Solution Overview
Problem
Existing methods fail to effectively control and minimize the crest factor of test signals, particularly in modern test techniques that require specific crest factor distributions across spectral bandwidths, such as in audio signals representing music, where crest factor varies in time and across narrow-band sub-bands.
Innovation Solution
A method for generating test signals composed of individual sinusoidal signals with adjustable phases, where the phases are set according to a general variable exponent P, allowing for the specification of a desired crest factor, enabling control of crest factor in both full-band and narrow-band sub-bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplitude of the input signal is increased to increase the signal-to-noise ratio, then the signal-to-noise ratio is improved, but the amplitude constraints are violated (non-linear behavior or overflow)
Solution Approach 1:
The patent changes the parameter distribution of the test signal by minimizing the crest factor through optimization of signal parameters. This allows the signal to maintain higher energy content without violating amplitude constraints, thereby improving signal-to-noise ratio while ensuring reliable operation within linear ranges.
2Measurement precision
If the energy of the signal is increased for a given amplitude extreme, then the signal-to-noise ratio is improved, but the crest factor control becomes more difficult
Solution Approach 1:
The patent employs an optimization algorithm that uses feedback from the calculated crest factor to adjust signal parameters iteratively. The algorithm calculates the crest factor, compares it to the target value, and adjusts the phase parameters accordingly until the desired crest factor is achieved, enabling automatic control of signal energy distribution.
3Reliability
If the crest factor is minimized to comply with amplitude constraints, then the reliability is improved, but the energy distribution becomes less optimal for certain measurement applications
Solution Approach 1:
The patent optimizes the phase parameters of the multi-tone signal to achieve a specific target crest factor. By changing the phase parameters through the optimization algorithm, the signal maintains reliable amplitude compliance while achieving optimal energy distribution for the intended measurement application, as the target crest factor can be selected based on measurement requirements.
4Device complexity
If a fixed crest factor is used for broadband signals, then the device complexity is reduced, but the ability to control narrow-band sub-band crest factors is lost
Solution Approach 1:
The patent segments the broadband signal into multiple narrow-band sub-bands and applies independent crest factor optimization to each sub-band. The optimization algorithm processes each frequency component or sub-band separately, allowing different crest factor characteristics to be achieved in different frequency ranges while maintaining overall signal coherence.
Data Source
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AI summary
A method for generating a signal having a defined bandwidth and a desired crest factor is disclosed. The signal is composed of a number of individual sinusoidal signals, each having an amplitude and a frequency. The method includes: determining an exponent to be used in a specific exponential function and corresponding to the desired crest factor, the exponent being determined based on an a priori known relationship between crest factor and exponent; calculating a phase value for each sinusoidal signal using the specific exponential function and the previously determined exponent; and superposing the sinusoidal signals to obtain the signal having the desired crest factor, whereby the phases of the individual signals are maintained.