jfa0522@hertz.njit.edu (john f andrews ece) (02/28/91)
From: jfa0522@hertz.njit.edu (john f andrews ece)
Newsgroups: comp.dsp
Subject: Binary Data formats
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Organization: New Jersey Institute of Technology, Newark, N.J.
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While I am not sure if this is the *best* group for such a post, I do believe
the readership is likely to garnish the experience and expertise to address
the issue, so here goes...
I am faced with the uncertain task of decyphering the data files created by
an instrument with missing documentation. The instrument stores the data to
DOS-compatible diskettes, for "later retrieval and analysis". Problem is the
data format is unknown and the manufacturer has been unable to provide details
(or unwilling...I am third party here... my thesis may depend on accessing
the data).
Preliminary investigation by someone else has reveals the data is in a
binary format. This individual questions my potential ability to do any
better than he has with the task over the past year, and has asked what I
know about binary data formats. Presumably if I know less than he, he will
not share the task with me.
What I do know is the basic BCD and packed-BCD formats from my 360/370
assembly course.... so what I am looking for his some direction for learning
what the possibilities are for this type of data. Any ideas? Every suggestion
welcome and appreciated.
In case it makes any difference, the Instrument is a DANTEC electromyography
instrument, out of Norway, I think.
Thanks for ay and all suggestions.
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john f andrews SYSOP The Biomedical Engineering BBS
24 hrs 300/1200/2400 (201) 596-5679
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INTERNET jfa0522@hertz.njit.edu LabRat@faraday.njit.edu CIS 73710,2600
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rbl@nitrex.UUCP ( Dr. Robin Lake ) (03/15/91)
In article <2468@njitgw.njit.edu> jfa0522@hertz.njit.edu (john f andrews ece) writes: |>From: jfa0522@hertz.njit.edu (john f andrews ece) |>Newsgroups: comp.dsp |>Subject: Binary Data formats |>References: |>Sender: |>Followup-To: |>Distribution: world |>Organization: New Jersey Institute of Technology, Newark, N.J. |>Keywords: |> |> |> ... |>I am faced with the uncertain task of decyphering the data files created by |>an instrument with missing documentation. The instrument stores the data to |>DOS-compatible diskettes, for "later retrieval and analysis". Problem is the |>data format is unknown and the manufacturer has been unable to provide details |>(or unwilling...I am third party here... my thesis may depend on accessing |>the data). |> |>Preliminary investigation by someone else has reveals the data is in a |>binary format. This individual questions my potential ability to do any |>better than he has with the task over the past year, and has asked what I |>know about binary data formats. Presumably if I know less than he, he will |>not share the task with me. |> |>What I do know is the basic BCD and packed-BCD formats from my 360/370 |>assembly course.... so what I am looking for his some direction for learning |>what the possibilities are for this type of data. Any ideas? Every suggestion |>welcome and appreciated. |> From what I know about Biomed data acquistion gear, it is likely the *DATA* portion of the information is stored in integer binary. It could be one's complement, but more likely two's complement. A rare alternative is magnitude and sign. If you knew what the hardware and operating system were, you would be way ahead. EMG signals are typically bandlimited and/or filtered at a few hundred cycles per second --- and a BASIC program may have been used for acquisition. In this case, the format may well be floating point instead of integer. The problem is that there are few standards for PC BASIC floating point: the mantissas and exponents vary in bit size and offset. Have you scanned the diskette with an octal dump program? Can you see ASCII characters anywhere? Important because once you psych out the *DATA* format you have the challenge of psyching out the *FILE* format, so that you can tell where one file ends and the next begins --- and separate out any extraneous file header information (if it exists within the file and not just in a directory at the beginning of the diskette.) In similar previous instances, I've found that a few phone calls to the manufacturer (in Norway) can lead to identification of who put the product together in the first place. It may be just relabelled or put together in a mountain retreat by elves --- and once you get the phone number of the person who *really* built it, you will have your answer! P.S. Based on my 3 decades of involvement with biomedical graduate education, I'd suspect you are getting a funny deal from whoever holds this data. It would help your career if you got into a project with *real* *usable* data and a sound scientific hypothesis. But, then again, I've been wrong more than once ... ! Rob Lake BP Research rbl@BP.COM |>In case it makes any difference, the Instrument is a DANTEC electromyography |>instrument, out of Norway, I think. |> |>Thanks for ay and all suggestions. |> |> |>----------------------------------------------------------------------------- |>john f andrews SYSOP The Biomedical Engineering BBS |> 24 hrs 300/1200/2400 (201) 596-5679 |>----------------------------------------------------------------------------- |>INTERNET jfa0522@hertz.njit.edu LabRat@faraday.njit.edu CIS 73710,2600 |>----------------------------------------------------------------------------- |> |> |> |> |> |> |>