MxArray: A Modular, Multiplexed, and Massive MEMS-Based Acoustic Array

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is well structured, research scope is clear, and methodology seems scientifically sound, and presented results are very tangible, with clear practical value. Language is OK, and graphical materials are prepared in a sufficiently high quality. I recommend accepting this paper for publication.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

 I am not a specialist in electronics and  data acquisition and can estimate the paper from a user’s perspective only.  I find the described acoustic array very impressive. Access to a similar system would be a valuable addition to my testing environment.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The work is well presented, which can be accepted in present form.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Good and interesting work. Here are some comments related with some issues that should be improved:

Highlights:

• In “Main findings”, I think that it’s better to write:
  • Research and development of a scalable...
  • Microsecond synchronization across

2.1 section:

• (At the end of page 4) If, in practice, each of your microphones outputs 24-bits audio data, why do you use a 32-bit word length to calculate the bit clock frequency? This idea is also related with the data rate calculation that you have carried out in section 3.2.

2.4 section:

• (At the end of page 6) Why r_max must be smaller than 0.2m? You should explain this.

2.5 section:

• (At the beginning of page 8) Are sync and clk lines buffered from the microphones to the BBB, or are they buffered on the opposite direction?

3.2 section:

• (At the end of page 9) I suppose that the 384ms time window is always enough, but are this time window reached in any case? How far from this value are the computational times?

4.1 section:

• (At the beginning of page 11) “minimizeing” is wrong.

5.2.2 section:

• (At the end of page 12) I think that Figure 8(b) is more related with Figure 9 than with Figure 8(a)...
• You should explain better terms on equation (6), and include in the text the specific representations (symbols) of the parameters used in this equation.

6.1 section:

• Figure 11(b): Are you showing “Grades” of “Phases”?

6.2 section:

• You should explain better how you obtain all the data shown in Figure 12, and the meaning of these obtained data.

6.4 section:

• Figure 14: In the text under the figure you talk about a “dashed” line, and there are not dashed lines in the figure.
• Table 1: Is it the clock offset related with node 106 the maximum value obtained? If it is, you should indicate it in the text, and if not, you should show the maximum value for this parameter in the table.

7 section:

• I think that you should combine chapters 6 and 7, in order to show the results (figures, data) with the corresponding discussions.
• At the end of the first paragraph, you say that the method was effectively validated at more than double the bandwidth of your results. Why don’t you also include the corresponding results?
• At the third paragraph you say that according to the microphone’s datasheet, with a sampling rate at 48kHz, the propagation delay is of 2ns. Ok, but you have used a sampling rate of 8kHz, so, what are the implications of this change?
• At the fourth paragraph you talk about the TDM transmission, about the period needed to synchronize and manage it, but I don’t really see the direct relation with the microphone ASIC and the WS signal. Or how it is related to those other measurement systems that you talk about. You should explain all this better.

References:

• In the second reference, the name of the paper is among the author’s names...
• Those references that can be accessed on the Internet should include the corresponding url.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf