Data Acquisition System - RF Cafe Forums

 Post subject: Data Acquisition System

Posted: Tue Aug 31, 2010 10:01 pm 

Hey guys,

Not sure if this is the best place to ask this question since this is kind of 'software' related. But since it is for an RF application and you guys might have had experience with it, I am hoping you can help me out.

I am just starting out as a student and as part of my project work, I am supposed to complete a Data Acquisition System for a commercially available digital receiver, all in Linux. I completed the driver development part for the digital receiver. But I am still struggling with the rest - the actual data acquisition program, what do headers mean, what information they convey, how are they supposed to be programmerd, how to build a GUI and a software scope for the data. I have no prior experience in coding for any of these requirements. Kindly help me out - I do not want any direct answers or cookbook recommendations but a general direction in which I should proceed and the concepts I need to learn to eventually be able to complete the task.

Thanks!

 Post subject: Re: Data Acquisition System

Posted: Wed Sep 01, 2010 11:43 am 

Hi Sandeep,

Without knowing much about the application, here are some things that you would want to look at. From your description, it looks like you are building a software interface to communicate with and acquire digitized data from some source.

Here are some things that I would look to do before you start writing code:

1. Write down all the functions you need the software to perform. Once you identify the functions, does there have to be a sequence for these functions, or are they user (or event) driven.

2. Is there a control signal that is used to start/stop acquisition. If so, where does that signal originate - is it a user input or is it from another piece of hardware. If it is hardware, does your code have to control that piece as well.

3. Identify the outputs you need to display. And the source of these outputs. What is the type of display you need for each data type.

Create a flow chart and identify as many pieces of the process as you can. Identify the relationships between different sections if any. That should get you started. Once you have that figured out, then you can look at implementing each block of the flowchart probably as modules and tie them all together, reusing as many blocks as you can.

To answer your question on the header, in a lot (most) of cases, the header section of the data packet consists of information that is needed to parse the rest of the packet. Headers can contain start bits (or characters/sequences of characters) to identify start of a packet, number of bytes being transferred, timestamps, etc. There is no fixed definition for headers, unless your packet structure conforms to a particular protocol. If you are defining your own packet structure, the header is up to you.


Karthik

 Post subject: Re: Data Acquisition System

Posted: Wed Sep 01, 2010 8:48 pm 

Thanks Karthik!

That helps! I will get started on that and post updates and if necessary ask further questions!