Transmitting

Communication protocols tests

UDP Test

Though we tried to work on the Red Pitaya WebApp, so far, what was successful was to used the | UDP Protocol get send and receive data.

To resume working with the RedPitaya data, without being actually connected to it, we have developed something to pursue Emulating the Red Pitaya through UDP

Data preparation

We had fun with the logs we had at the previous Compressing with FFT

Data rate for our prototype

We calculate in this section the frame and the data quantity that we will need to send with our image specification(CAPTech section Image impact on tech - First level) and compare it to the one of the phd of Philippe Levesque (for the data quantity), cf. information given on CAPTech, section benchmark.

Here we consider that the speed of sound c is equal to 1540 m.s^{-1}.

For our purpose we have:

  • measurement width: d from 50 to 200 mm
  • sector angle: s = \pi/3
  • lateral resolution: r_l = 1 mm
  • number of lines: N_l = sR (R is the maximum with) = 210

In the phd of Philippe Levesque, we have:

  • measurement width d = 150 mm
  • sector angle: s = \pi/2
  • number of lines: N_l = 240
  • frame rate: f_r = 15 fps

Data quantity

The data quantity to send depend on either the raw data or filtered data. Problem is the raw data correspond to a high quantity of data and can't be sent via USB or WIFI to a smart phone or a computer. One solution can be to send filtered data as we show below.

Raw data

The quantity of data Q per second sampled by a probe is given by:

Q = npN_lf_r, (4)

where n is the number of point on each line:

n = \dfrac{2d}{c}f_e. (5)

Considering the parameter of Philippe Levesque for example, Q = 137 and 687 Mbps and for f_e = 20 and 100 MHz respectively. With our parameter (considering f_r = 15 fps), Q = 468, 585 and 702 Mbps for p = 8, 10 and 12 bits respectively.

Filtered data

If you filter data on a bandwidth \Delta f, then you only have to send the data of the Fourier Transform of the signal between this bandwidth (center on the central frequency of the transducer), cf. the wiki page on the introduction to acoustic imaging. The total quantity of data is then:

Q = n\dfrac{\Delta f}{f_e}pN_lf_r = \dfrac{4d}{c}\Delta f pN_lf_r. (6)

It appears that with this method the data quantity does not depend anymore on the sampling frequency.

Considering the parameters of Philippe Levesque and \Delta f = 4MHz, the Q reduces to 53.5 Mbps. With our parameters we have Q = 37.5, 47 and 56 Mbps. This data rate can be trasmitted via WIFI or USB for example.

Media in category "Transmitting"

The following 13 files are in this category, out of 13 total.

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