A Method for Optimizing Phase Continuity and Transition Section of Stepped Sweep Signal

Abstract

The present invention relates to the technical field of audio signal processing, and particularly relates to a method for optimizing the phase continuity and transition section of a stepped frequency sweep signal; constructing a signal model to generate a stepped frequency sweep signal; optimizing the phase continuity; optimizing the transition section; synthesizing a signal, generating signals for each stepped section according to the optimized phase and transition section, inserting the optimized transition section signal between the signals for each stepped section, and splicing them to generate a complete stepped frequency sweep signal. By the above method, the effect of improving the overall quality of the audio signal and the measurement accuracy of the test system is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of audio signal processing, and particularly to a method for optimizing the phase continuity and transition section of a stepped sweep signal. Background Art

[0002] Stepped sweep signals are widely used in audio testing, acoustic measurement, and performance evaluation of high-fidelity audio systems. In the traditional stepped sweep signal, during the frequency conversion process, phase discontinuity is likely to occur, resulting in signal spectrum distortion, waveform distortion, and quality degradation. In addition, improper processing of the transition section during frequency switching often introduces spectrum leakage and noise, seriously affecting the accuracy and reliability of measurement results.

[0003] Therefore, it is very necessary to propose a method for optimizing the phase continuity and transition section of a stepped sweep signal to improve the overall quality of audio signals and the measurement accuracy of the test system. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for optimizing the phase continuity and transition section of a stepped sweep signal, achieving the effect of improving the overall quality of audio signals and the measurement accuracy of the test system.

[0005] To achieve the above purpose, a method for optimizing the phase continuity and transition section of a stepped sweep signal adopted by the present invention includes the following steps:

[0006] Construct a signal model to generate a stepped sweep signal;

[0007] Optimize the phase continuity;

[0008] Optimize the transition section;

[0009] Synthesize the signal. According to the optimized phase and transition section, generate each stepped segment signal, insert the optimized transition section signal between each stepped segment signal, and splice them to generate a complete stepped sweep signal.

[0010] Among them, in the step of constructing a signal model to generate a stepped sweep signal:

[0011] Define the stepped sweep signal, set the initial frequency f 0 , the frequency step size Δf, the number of steps N, and the duration T of each step;

[0012] The signal expression is adopted as: The stepped sweep signal can be expressed as: where n is the current stepped sequence, is the initial phase of each step;

[0013] Calculate the frequency coverage range: f min = f 0 ; f max = f0 +(N - 1)Δf。

[0014] Among them, in the step of optimizing phase continuity:

[0015] Set the initial phase and determine the initial phase of the first frequency f 0 of the initial phase

[0016] Calculate the phase for each step:

[0017] Correct the phase cumulative error, adopt the phase offset correction method, and perform phase fine-tuning. The fine-tuning formula is:

[0018] Smooth the phase, and optimize the phase continuity by sampling the high-order zero-phase filtering smoothing algorithm.

[0019] Among them, in the step of optimizing the transition section:

[0020] Set the transition section length and determine the transition section length for each frequency step;

[0021] In the transition section of the frequency step switching, use the Bessel interpolation method to interpolate the signal in the transition section;

[0022] Generate the transition section interpolation data according to the interpolation algorithm: s(t) transition = Interpolate(s(t), Δt); where Δt is the interpolation time interval;

[0023] Apply the weighted window function, and apply the high-efficiency weighted window function in the transition section. The function is: s(t) transition = s(t) * w(t); where w(t) is the transition section window function designed precisely.

[0024] Among them, in the step of synthesizing the signal, generating the signal for each step section according to the optimized phase and transition section, inserting the optimized transition section signal between the signals for each step section, and splicing them to generate the complete stepped frequency sweep signal:

[0025] Generate the signal for each step section, and generate various signals for each step section according to the optimized phase and transition section;

[0026] Insert the transition section signal, and insert the optimized transition section signal between the signals for each step section;

[0027] Splice and synthesize the signal, splice the signals for each step section and the transition section signal to generate the complete stepped frequency sweep signal:

[0028] Among them, after the step of splicing and synthesizing the signal:

[0029] Verify and correct the signal, perform spectral analysis and phase verification on the synthesized signal, and perform correction according to the analysis results;

[0030] Output and apply the signal, output the optimized stepped frequency sweep signal, and apply it to audio device testing, acoustic measurement, and performance evaluation of high-fidelity audio systems.

[0031] A method for optimizing the phase continuity and transition section of a stepped frequency sweep signal of the present invention generates a stepped frequency sweep signal by constructing a signal model; optimizes the phase continuity; optimizes the transition section; synthesizes the signal, generates each stepped section signal according to the optimized phase and transition section, inserts the optimized transition section signal between each stepped section signal, and performs splicing to generate a complete stepped frequency sweep signal; obtains the effect of improving the overall quality of the audio signal and the measurement accuracy of the test system. Brief Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 It is the combined effect diagram of a common stepped frequency sweep.

[0034] Figure 2 It is the combined effect diagram of the stepped frequency sweep processed by the present invention.

[0035] Figure 3 It is the spectral comparison diagram of the single-step frequency of the common stepped frequency sweep and the stepped frequency sweep optimized by the present invention.

[0036] Figure 4 It is the algorithm flow chart for optimizing the phase continuity and transition section of the stepped frequency sweep signal in the embodiment of the present invention.

[0037] Figure 5 It is the schematic diagram of the signal synthesis principle steps of the present invention.

[0038] Figure 6 It is the step flow chart of the method for optimizing the phase continuity and transition section of the stepped frequency sweep signal of the present invention. Detailed Embodiment

[0039] Please refer to Figures 1 to 6 where Figure 1 is the combined effect diagram of the common stepped frequency sweep, Figure 2 is the combined effect diagram of the stepped frequency sweep processed by the present invention, Figure 3It is a spectrum comparison diagram between ordinary step - sweep frequency and the single - step frequency of the optimized step - sweep frequency by the present invention. Figure 4 It is a flowchart of an algorithm for optimizing the phase continuity and transition section of a step - sweep signal in an embodiment. Figure 5 It is a step diagram of the signal synthesis principle. Figure 6 It is a flowchart of the steps of the method for optimizing the phase continuity and transition section of a step - sweep signal.

[0040] The present invention provides a method for optimizing the phase continuity and transition section of a step - sweep signal, including the following steps:

[0041] S100: Construct a signal model and generate a step - sweep signal.

[0042] The specific process is as follows: Define a step - sweep signal, set the initial frequency f 0 = 20Hz, the frequency step Δf, the number of steps N, and the duration T of each step; The signal expression is used: The step - sweep signal can be expressed as: where n = 121 is the current step sequence, is the initial phase of each step; Calculate the frequency coverage range: f max = 20 * 1.059 121 ; f max = 20579.8Hz.

[0043] For the parameter selection of the signal model, in order to meet the requirements of different application scenarios, the initial frequency, frequency step, number of steps, and duration of each step can be adjusted according to specific needs to generate a step - sweep signal that meets the actual test requirements.

[0044] S200: Optimize the phase continuity.

[0045] The specific process is as follows: Set the initial phase, determine the initial phase 0 of the first frequency f Calculate the phase for each step: Correct the cumulative phase error, adopt the phase offset correction method for phase fine - tuning, and the fine - tuning formula is: Smooth the phase, and optimize the phase continuity by sampling the high - order zero - phase filtering smoothing algorithm.

[0046] The phase continuity optimization method has high real - time performance, can quickly adjust the phase at the moment of frequency step - by - step switching, ensure the continuity and stability of the signal, and is applicable to real - time audio test and measurement scenarios.

[0047] S300: Optimize the transition section.

[0048] The specific process is as follows: Set the length of the transition section and determine the length of the transition section for each frequency step. In the transition section during the frequency step switching, the length of the transition section is set to T transition = 10 ms, and the Bessel interpolation method is used to interpolate the signal in the transition section. According to the interpolation algorithm, the interpolation data in the transition section is generated where B i (t) is the Bessel basis function, c i is the interpolation coefficient, and M is the number of interpolation points. Apply the weighted window function. Apply the Kaiser window function in the transition section to reduce spectral leakage x window (t) = x(t) * w(t), where w(t) is the Kaiser window function.

[0049] The transition section optimization method is not only applicable to frequency step switching, but also applicable to the transition section processing in signal processing such as amplitude modulation and phase modulation, and has a wide application range and practicability.

[0050] S400: Synthesize the signal. According to the optimized phase and transition section, generate the signals for each step section, insert the optimized transition section signal between the signals for each step section, and splice them to generate a complete stepped frequency sweep signal.

[0051] The specific process is as follows: Generate the signals for each step section. According to the optimized phase and transition section, generate various signals for each step section; Insert the transition section signal. Insert the optimized transition section signal between the signals for each step section; Splice and synthesize the signal. Splice the signals for each step section and the transition section signal to generate a complete stepped frequency sweep signal: Verify and correct the signal. Perform spectral analysis and phase verification on the synthesized signal. According to the analysis results, perform correction to ensure that the signal quality meets the expected standard; Output and apply the signal. Output the optimized stepped frequency sweep signal and apply it to audio device testing, acoustic measurement, and performance evaluation of high-fidelity audio systems.

[0052] In this embodiment, by optimizing the phase continuity of the stepped sweep signal and the smoothing process of the transition section, the signal spectrum distortion and waveform distortion are effectively reduced, thereby improving the overall quality of the audio signal; by optimizing the phase continuity of the stepped sweep signal and the smoothing process of the transition section, the signal spectrum distortion and waveform distortion are effectively reduced, thereby significantly improving the overall quality of the audio signal; by adopting the high-order zero-phase filtering algorithm and the Bessel interpolation method, the phase continuity and smooth transition of the signal are ensured, the spectrum leakage and noise interference are reduced, and the accuracy and reliability of the audio test and measurement system are greatly improved; by setting a reasonable transition section length and using weighted window functions such as Kaiser window for processing, the transient effect caused by frequency mutation is reduced, and the smoothness and stability of the signal transition are ensured; the phase continuity optimization method has high real-time performance and can quickly adjust the phase at the moment of frequency step switching, which is applicable to real-time audio test and measurement scenarios. The effects of improving the overall quality of the audio signal and the measurement accuracy of the test system are obtained. The research on the phase continuity and transition section optimization method of the stepped sweep signal has important application value in engineering practice.

[0053] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for optimizing phase continuity and transition section of a stepped frequency sweep signal, characterized in that: The steps include: Build a signal model and generate a step-and-sweep frequency signal; Optimize phase continuity; Optimize transition section; Synthesize the signal, generate each step segment signal according to the optimized phase and transition segment, insert the optimized transition segment signal between each step segment signal, and splice them to generate a complete step frequency sweep signal; In the steps of building a signal model and generating a step-sweep frequency signal: Define the step frequency sweep signal, set the initial frequency f0, frequency step length Δf, number of steps N and duration of each step T; The signal expression used is: The step frequency sweep signal can be expressed as: Where n is the current step sequence, is the initial phase of each step; Calculate frequency coverage: f min =f0;f max =f0+(N-1)Δf; In the step of optimizing phase continuity: Set the initial phase and determine the initial phase of the first frequency f0 Calculate the phase for each step: Correct the phase cumulative error and use the phase offset correction method to perform phase fine-tuning. The fine-tuning formula is: The phase is smoothed and a high-order zero-phase filter smoothing algorithm is sampled to optimize phase continuity; In the step of optimizing the transition: Set the transition length to determine the transition length of each frequency step; In the transition section of frequency step switching, the Bessel interpolation method is used to interpolate the signal of the transition section; According to the interpolation algorithm, generate transition segment interpolation data: s(t) transition =Interpolate(s(t),Δt); where Δt is the interpolation time interval; Apply a weighted window function and apply an efficient weighted window function in the transition section. The function is: s(t) transition =s(t)*w(t); wherein w(t) is a precisely designed transition window function.

2. The method for optimizing phase continuity and transition section of a stepped frequency sweep signal according to claim 1, characterized in that: In the step of synthesizing the signal, generating each step segment signal according to the optimized phase and transition segment, inserting the optimized transition segment signal between each step segment signal, and splicing them to generate a complete step frequency sweep signal: Generate step segment signals, and generate each step segment signal according to the optimized phase and transition segment; Inserting transition segment signals, inserting optimized transition segment signals between each step segment signal; Splice and synthesize signals, splice each step segment signal with the transition segment signal to generate a complete step frequency sweep signal:

3. The method for optimizing phase continuity and transition section of a stepped frequency sweep signal according to claim 2, characterized in that: After the steps of concatenating and compositing the signals: Verify and correct the signal, perform spectrum analysis and phase verification on the synthesized signal, and make corrections based on the analysis results; Output and application signals, output optimized stepped frequency sweep signals, applied to audio equipment testing, acoustic measurement and performance evaluation of high-fidelity audio systems.

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