I am Working on a new project which is based on Under water communication? I need help with the desigin of a specific hardware namely a USB DAC. The function is simple to take samples at almost at the rate of 40,000 using a 24bit precision DAC

 

The obvious solution involves providing ADEQUATE water-proof sealed packaging.
AND, the rate is 40,000 What??
With a 24 bit A/D that will be a rather demanding setup.

 

Why do you need 24-bit resolution for communication?

What kind of waveform are you using?

Assuming that your 40,000 is meant to be 40,000 samples per second, that seems like it might be audio. Is it?

 

I am guessing that what is being sent is a data stream of the digitized wide-band underwater audio. But why USB, except for it being cheap and sort of easy?? There are certainly better schemes and formats for fast data, and the wired ones all use a more rugged cable style than USB.

 

https://www.amazon.com/LornCeng-Ext...keywords=usb+over+fiber&qid=1721791490&sr=8-5

 

Certainly using fiber optics is a valid choice, given the desired data rate. But do power considerations get into the consideration?? AND, "a USB DAC" which I read as "a Universal Serial Bus Digital to Analog Converter" . That would be a somewhat strange item as I see it.

 

Certainly using fiber optics is a valid choice, given the desired data rate. But do power considerations get into the consideration?? AND, "a USB DAC" which I read as "a Universal Serial Bus Digital to Analog Converter" . That would be a somewhat strange item as I see it.

The whole question is strange. Is OP requesting help with designing a USB DAC? Or how to communicate with a USB DAC under water?
I chose to interpret the latter as it is something I actually know about. In a previous role I designed control systems for subsea tools and ROV implements, so I am familiar with the conventional ways of "under water communication." It is almost always fiber optic, with the fiber being a component of a subsea umbilical cable which also carries power conductors.

 

I am Working on a new project which is based on Under water communication?

Um, that's a question. My answer "You are? Cool".
Unfortunately, OP has tossed a thread starter out there and then not come back to fill in the details.
In my many years of working with product managers and insufficient requirement, I have learned not to speculate on what you think they want until they tell you. Even if you need to torture it out of them (obviously not applicable here).

 

C AND, "a USB DAC" which I read as "a Universal Serial Bus Digital to Analog Converter" . That would be a somewhat strange item as I see it.

https://www.ti.com/product/PCM2904?...5NshECZsw6GUx7VXUyh24k7iALhMYvJORY36VGRHU72K1

 

I need help with the desigin of a specific hardware namely a USB DAC. The function is simple to take samples at almost at the rate of 40,000 using a 24bit precision DAC

Take samples from a DAC? Don’t we usually send samples to a DAC?

Did you mean ADC?

 

It could be a Data Acquisition Computer (DAC) I have used those. Some are normal computers until the software is loaded on. And we are getting a fair question from somebody who is not an "electronic instrumentation master" engineer.
So we should be gentle.

 

It could be a Data Acquisition Computer (DAC) I have used those. Some are normal computers until the software is loaded on. And we are getting a fair question from somebody who is not an "electronic instrumentation master" engineer.
So we should be gentle.

Look what he said in the post #1--
The function is simple to take samples at almost at the rate of 40,000 using a 24bit precision DAC.

DAC - Digital to Analogue Conversation
And the title -- USB-Transceiver
So I guess that he could be trying to do this way --
uC(or Computer) → 24 Bits DAC → USB → USB → 24 Bits ADC → uC(or Computer)

 

It does not seem likely that an analog signal would be sent by means of a USB connection. With the possible exception of battery charging schemes, My impression is that USB is DIGITAL. So an analog signal over a fiber-optic line would not use USB protocol or format. UNLESS there has been a major breakthrough that I am not aware of.
And accurate analog at 24 bit resolution over a long fiber optic cable does not come across as a simple or easy task!!

 

I assumed he meant DAQ, a USB data acquisition module like a labjack. Not that it matters, he is never coming back.

 

The function is simple to take samples at almost at the rate of 40,000 using a 24bit precision DAC

This use of DAC is the one I question. I think he means ADC.

 

USB DAC.

 

guys, I am really sorry for not making myself clear. long story in short i want to design a specific hardware for an under water communication system just like the USB 4431(https://www.ni.com/en-in/shop/model/usb-4431.html). the issue is that i found out that this hardware is only compatible for windows machine. I am trying to design the same device with linux capabilities from scratch. after some research i found that stm32h7 series is the way to go and to use its built in ADC (sorry for saying the 24 bit DAC earlier). I just found this project amazing that is why i want to built it myself from scratch and I am kind of new to the stm family. Can anyone help me with the setup that I should be working on or is there any reference material that i can find for this project.

 

If this is a project in which you're only going to devote 90 seconds of mediocre work every two weeks then you're better off buying a Hantek USB oscilloscope. The 6022 is an actual oscilloscope and has full linux software. The 1008 has twice as many channels as the NI product, is several times faster, and only cost $100. There is not linux software for it but there is a linux driver and you could write your own data collection software.

 

well thanks for the reply. I am acually doing this project as my main project now, I have also engaged one of my proffessors with this project. The fact that the main goal is to build the entire system which is both linux and windows capable, if not both atleast linux as the main machine. I have also attached the block diagram of how the system is supposed to work.

 

You need to take a couple of steps backward, explain what is the big picture scenario, what is the application, and how your project fits into it. Your block diagram seems like it could be informative if I knew what you're trying to do, but I still don't, so all it does is confuse me further.

For example, from the understanding that I have (which I am sure is wrong) I would expect "Linux system" to be at the right, after "transmitted data" but instead it is at the bottom below "OTG." this makes no sense to me because I don't understand the purpose of any of those blocks actually, in the absence of an overall understanding of the whole project. And why is there a DAC and amplifier between DMA and transmitted data? Are you doing analog communication to topside? I thought the whole point of this thing is to collect analog signals and relay them to topside with digital communication (USB, over fiber or coax presumably).