A High-Precision Gated Integrator for Repetitive Pulsed Signals Acquisition

Round 1

Reviewer 1 Report

The paper introduces a gated integrator prototype for conditioning and acquisition of repetitive input pulsed signals with a sync.

The paper is clear and easy to read, although novelty is very low.

Authors must answer some questions:

Paper is focused on the linearity and SNR performance. Many figures show that, but a new figure showing the averaging effect will help; i.e., since SNR improves at a square(samples) rate, show this behavior in your prototype.

Authors propose a differential measurement method to remove offset errors. But this is a standard procedure, e.g., in image sensors (Correlated double sampling CDS). What is the novelty? Or at least some comments/discussion addressing how your method relates to or is different.

Figures and data are helpful, but some values are given in a strange unit system, especially those concerned to noise, e.g.:

202 with an additive white noise signal having a 0.5µApp amplitude

Use SNR value or at least specify the variance (noise power) since amplitudes make no sense for random variables. I guess a 0.5µApp amplitude (noise) is the value given by the equipment authors use to add noise but this value must be explained (at least give the equation it relates your “noise amplitude” to real noise variance or better yet SNR case under study (since you know your signal value).

The same for the rest of noise values that appear in the paper (noise intensities); please, state clearly how they are related to noise power or white noise variance.

240 the relative error, calculated with respect the nominal expected values, is lower than ±0.4% in the investigated range

Again; it is better if authors use standard variables in statistics nomenclature to refer to the performance of a linear regressor, e.g., R squared or similar values.

Author Response

RESPONSE TO REVIEWER 1

Dear Referee, we found helpful your suggestions especially regarding the way to show in a more technical way the noise parameters. We identified the following four questions and improved the paper accordingly.

The paper introduces a gated integrator prototype for conditioning and acquisition of repetitive input pulsed signals with a sync. The paper is clear and easy to read, although novelty is very low.

Authors must answer some questions:

Paper is focused on the linearity and SNR performance. Many figures show that, but a new figure showing the averaging effect will help; i.e., since SNR improves at a square(samples) rate, show this behavior in your prototype.

This question is really meaningful for the paper improvement. We added a new figure (figure 9) showing the experimental verification of the theorized square(samples) behaviour.

Authors propose a differential measurement method to remove offset errors. But this is a standard procedure, e.g., in image sensors (Correlated double sampling CDS). What is the novelty? Or at least some comments/discussion addressing how your method relates to or is different.

Referee is right; a similar approach is also used for low-level signals in CMOS image sensors. Such technique called CDS (Correlated Double Sampling) removes the noise by differencing sampled values taken from the same pixel before and immediately after the gate opening. While in such field it is important time proximity between the two different charge integration and for this reason the measurement charge is accumulated onto different capacitances; in our system developed on-purpose for dosimeters it may be even detrimental to use such a close time gap because of uncorrelated electromagnetic noise from high-power electronic present in LINAC bunker. For such reason, we let user-programmable the delay time between the two measurements by simply changing match 5 event. In such a way, the optimum condition may be achieved in future on-field calibration.

Figures and data are helpful, but some values are given in a strange unit system, especially those concerned to noise, e.g.: line 202 “with an additive white noise signal having a 0.5µApp amplitude”. Use SNR value or at least specify the variance (noise power) since amplitudes make no sense for random variables. I guess a 0.5µApp amplitude (noise) is the value given by the equipment authors use to add noise but this value must be explained (at least give the equation it relates your “noise amplitude” to real noise variance or better yet SNR case under study (since you know your signal value). The same for the rest of noise values that appear in the paper (noise intensities); please, state clearly how they are related to noise power or white noise variance.

Same as for comment n1. We now used SNR values in the relative experimental results.

Line 240: “ the relative error, calculated with respect the nominal expected values, is lower than ±0.4% in the investigated range”. Again; it is better if authors use standard variables in statistics nomenclature to refer to the performance of a linear regressor, e.g., R squared or similar values.

We now used the R squared value of the linear fit.

Author Response File: Author Response.pdf

Reviewer 2 Report

I really like the reviewed manuscript.

In my opinion it can be published without major changes.

My remarks:

Language can be improved (there are some grammatical errors) and the whole manuscript should be edited with an eye for a clear communication. Long paragraphs and sentences (eg. l. 61-65) makes the manuscript not easy to follow for potential reader. In particular, the last paragraph of the Introduction section needs to be split, and purpose and scope of work clearly indicated. In my opinion Introduction begins too sudden. Few words on applications would be recommended. Also, clumped references should be avoided (l.40). It is worth placing a good quality picture of the prototype as additional figure. It is worth supplementing the work with a brief justification for the choice of key components (op-amp, ADC, uC...), together with an indication of their crucial parameters.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf