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Re: [Discuss-gnuradio] Spectrum sensing using gnuradio + hackrf one


From: CEL
Subject: Re: [Discuss-gnuradio] Spectrum sensing using gnuradio + hackrf one
Date: Wed, 13 Mar 2019 08:05:33 +0000

You'd need to write your own block that can handle these formats.

A word of warning: When doing SDR, you deal with MEGASAMPLES per
second.

A 32 bit floating point number has circa 9 significant digits.
That makes 10 characters when you include the decimal dot.
Then you also need to write down the exponent, that's another 4
characters, and the sign (on average, half a character, you could omit
"+"). 
That makes on average 14.5 Bytes to represent a 4 Byte number.

You need one real and one imaginary part per sample, that's on average
29 Bytes.

Add one byte for the "," between these parts, and one byte for the
newline character.

You've just made 1 worth of samples at 1 MS/s take 31 MB on disk, where
it really only contains 4 MB of actual data, and still introduced
rounding errors.

Excell is not better. At least the modern excel format applies zip
afterwards.

And: no one will *ever* scroll through 1 Million samples in Excel.

Whatever the problem is, exporting millions of numbers to CSV or Excel
is not the solution; excel is really a tool primarily for accounting,
not for data analysis.

Best regards,
Marcus

On Tue, 2019-03-12 at 19:31 +0400, faisal wrote:
> hello everyone........
> can anyone help me i want to save data which comes from average block
> and threshold block.
> how can we save a date in text file or in an excel file?
> i attched the grc.file please have a look at it.
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

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