A Novel Battery-Supplied AFE EEG Circuit Capable of Muscle Movement Artifact Suppression
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsComments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors, My main concerns are about formal aspects, starting with the length of the article, which must be strongly reduced to less than, say, 15 pages. Please also consider the following observations:
- The subsection "The structure of the present study" is excessively long.
- Figure 5 is of unacceptable quality.
- Several statements throughout the paper are unclear or poorly justified. For instance, the phrase “...without the need for complicated techniques such as antialiasing filters” is questionable. Is an antialiasing filter truly a complicated technique? Is this sentence relevant? I don’t think so.
- Several figures dedicated to simple subcircuits are unnecessary, such as Figures 6, 7, 8, 9, and 14. The quality of Figures 17 and 18 must be improved (e.g., a white background would be better).
- Table 6: Why is a 3.5 MHz bandwidth required? This is quite excessive for electrophysiological signals.
- Circuit figures should generally be simplified by removing element names or tags, such as “U1,” “U2,” “R6,” or “R5” in Figure 10, or “D1,” “D2,” and “U5” in Figure 12, unless these references are needed in the text.
- Why are several resistors connected in series in Figure 13? It seems that only one equivalent resistor should suffice, doesn’t it?
- Many values are reported with an excessive (and unjustified) number of digits. For example, 𝑓0 calculated with Eq. 3 is reported as 50.2383 Hz, but I assume that 𝑅0 and 𝐶0 have associated errors (1%?, 10%?) that propagate to 𝑓0, resulting in an uncertainty greater than that suggested by the last digits. The same applies to 𝑓𝑐 with Eq. 5, 𝑅𝑓31, and 𝐶𝑓31.
- Overall, the article resembles an internal technical report meant for colleagues within the same team, rather than a scientific paper intended for a broader external community.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors present a comprehensive study on electroencephalography (EEG) signal processing and circuit design for muscle movement and artifact suppression.
Minor errors with value and units:
Line no - 199 it should be 50 Hz - there should be a space after the value
same as above for:
Table -2
Line 249
Table -3
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe introductory chapter, Introduction, is concise. It first covers general aspects of the EEG signal and the effects of noise on it. The second part provides an overview of the main components of an analog interface for acquiring EEG signals, along with the necessary specifications for medical and research purposes. While the information is well-organized, Appendix A is unnecessary as all the information is cited in the paper's references. Removing Appendix A and its references would enhance the clarity of the chapter.
The next chapter, "State of the Art," provides a brief overview of similar works found in the specialized literature. It includes a short presentation of several relevant works, excluding the more detailed discussion of the three examples presented in Appendix B. Delving into detailed descriptions of these works is unnecessary as the information is already available in the bibliographic references cited in the paper. While these works may be used for later comparison with the proposed circuit, an excessively long presentation might give the impression that the article is more of a review than a paper introducing a new circuit. Additionally, Appendix B is unnecessary as the information it contains is available in the bibliographic references cited in the paper, much like in the case of Appendix A.
The next chapter focuses on presenting the proposed circuit for acquiring EEG signals. It provides detailed descriptions of the constituent blocks and the circuit composed of voltage sources that model the EEG signal, along with other signals that can be captured by the real sensor. However, the resulting circuits are not included in the chapter; they are found in Appendix C, making their understanding more difficult. The decision to exclude the circuits from the main body of the work was based on considerations of space. Nevertheless, it may be necessary to refer to Appendix C to fully understand the circuits, raising questions about where space has been saved. Typically, an Appendix includes larger equations or circuits, not the small blocks that are central to this work. Therefore, it is recommended that electrical diagrams of the circuits, if not directly from specialized sources, be included in the main body of the work when they are mentioned, rather than being relegated to Appendix C. Additionally, relevant formulas, especially those that led to determining the component values, could also be included in the main body.
In the upcoming chapter, is presented the results from the circuit simulation in both the time and frequency domains. Section 4.1.1 provides the results of measurements in the frequency domain, but the corresponding graph(s) is missing. It would be beneficial to include these and indicate the measuring points where the mentioned values (e.g., CMRR) were read. The subsequent analyses in the time/Fourier domain only offer a qualitative analysis of the circuit's performance, rather than a quantitative one. When referring to signals, it would be helpful to use the name of the signal rather than its color. For instance, in Figure 7, it would be clearer to label the signal as "Raw EEG Channel 1 signal V(ch1) (gold)."
Some observations pertain to the second part, which compares the circuit with three cases from the literature. Specifically, in case 2, where only the amplification stage is discussed, comparing the "Circuit bandwidth" parameter seems irrelevant. It may be helpful to provide bibliographic references at the beginning of the table where the circuits used for comparison are listed, instead of simply labeling them as Cases "1," "2," and "3."
The first bibliographic reference is not presented correctly; only the DOI is provided in the reference section.
Please take note of the following points regarding the language used in the text. The language is generally clear, but there are some mistakes, such as the word "com-pound" in the Abstract, the repetition of "this study aims" in line 132, and a sentence in line 535 that starts and ends with "So,". There are a few more such instances. A further review of the article could address these mistakes, ideally by someone who was not involved in drafting the document.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsAlthough the manuscript improved in some aspects, the concerns have not been thoroughly addressed as expected. The article is still excessively long for a standard scientific publication.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThank you for revising the article. The changes improved its clarity and scientific quality.
