<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Fourth factor - data compression?<div class=""><br class=""></div><div class="">Phil M1GWZ</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 30 May 2017, at 18:19, Joe palsa via Tacos <<a href="mailto:tacos@amrad.org" class="">tacos@amrad.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class="">Food for thought-------
<p class="qtext_para" style="WHITE-SPACE: normal; WORD-SPACING: 0px; TEXT-TRANSFORM: none; COLOR: rgb(51,51,51); PADDING-BOTTOM: 0px; PADDING-TOP: 0px; FONT: 14px/21px q_serif, Georgia, Times, 'Times New Roman', serif; PADDING-LEFT: 0px; MARGIN: 0px 0px 1em; WIDOWS: 1; DISPLAY: block; LETTER-SPACING: normal; PADDING-RIGHT: 0px; TEXT-INDENT: 0px; -webkit-text-stroke-width: 0px">The
size of an audio file is determined by three factors: sampling rate, bit
resolution and channel count.</p><p class="qtext_para" style="WHITE-SPACE: normal; WORD-SPACING: 0px; TEXT-TRANSFORM: none; COLOR: rgb(51,51,51); PADDING-BOTTOM: 0px; PADDING-TOP: 0px; FONT: 14px/21px q_serif, Georgia, Times, 'Times New Roman', serif; PADDING-LEFT: 0px; MARGIN: 0px 0px 1em; WIDOWS: 1; DISPLAY: block; LETTER-SPACING: normal; PADDING-RIGHT: 0px; TEXT-INDENT: 0px; -webkit-text-stroke-width: 0px">Let's
take an example audio file which was recorded at 44.1kHz, mono, and 16 bit
resolution. The bit rate for this file is calculated as: 44100 x 1 x 16 =
705,600 bits per second. Divide that 705,600 by 8 and you've got 88,200 bytes
per second. Divide that 88,200 by 1024 and you end up with 86 kilobytes per
second. Multiple that by 60 and you get 5167 kilobytes per MINUTE. Or 5.047 MB
per minute.</p><p class="qtext_para" style="WHITE-SPACE: normal; WORD-SPACING: 0px; TEXT-TRANSFORM: none; COLOR: rgb(51,51,51); PADDING-BOTTOM: 0px; PADDING-TOP: 0px; FONT: 14px/21px q_serif, Georgia, Times, 'Times New Roman', serif; PADDING-LEFT: 0px; MARGIN: 0px 0px 1em; WIDOWS: 1; DISPLAY: block; LETTER-SPACING: normal; PADDING-RIGHT: 0px; TEXT-INDENT: 0px; -webkit-text-stroke-width: 0px"><font size="2" face="Arial" class="">The audio with more activity I would expect to require more
MB.</font></p></div>
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<div class="">73's<br class="">Dr Joseph Palsa k3wry<br class="">ARRL-Virginia Section Manager<br class="">Virginia
State Government Liaison<br class=""><a href="mailto:K3WRY@ARRL.ORG" class="">K3WRY@ARRL.ORG</a><br class="">804-350-2665<b class=""><br class=""><br class="">NOTICE: The
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E-mail. </b><br class=""><br class="">No trees were destroyed in the sending of this message,
however, a significant number of electrons were terribly inconvenienced "You are
what you do, When it counts"<br class=""><br class="">"When the disaster is at its worst,
communications should be at its best"</div>
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<div class="">
<div class="">In a message dated 5/30/2017 12:54:22 P.M. Eastern Daylight Time,
<a href="mailto:beatnic@comcast.net" class="">beatnic@comcast.net</a> writes:</div>
<blockquote style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid" class=""><font style="BACKGROUND-COLOR: transparent" size="2" face="Arial" class=""><font size="+1" face="Comic Sans MS" class="">I was thinking this morn, probably the
coffee. <br class="">So if you record to disk I would think that if you captured
a portion of the spectrum with many stations that the file size would be
greater than a less busy part of the spectrum. Is that true? Then I
thought if you recorded a part of the spectrum with noise at a certain level
and then recorded another part of the spectrum with a higher noise level, then
would the 2 files sizes be the same or different? I'm ignoring OS
overhead.<br class="">I'm sure there is a mathematical explanation for this and if need
be I WILL drink more coffee...<br class=""><br class="">Terry Fox wrote on 5/29/2017 8:46 PM:
<blockquote type="cite" class="">I have recently purchased three new SDRs for testing
and playing with. Up front: I have NO RELATIONSHIP with any of
these companies, other than being a customer, who paid full-price for
everything. <br class=""><br class="">1/2: BooyaSDR <br class="">The first two are BooyaSDR
units. These are different than almost all other SDRs available to RF
enthusiasts at the moment, in that they sample the RF input directly, then
send ALL those samples to the host computer. No FPGA or other device
to reduce the amount of samples. The host computer then does all the
computations to show the FULL bandwidth of their respective input. The
software shows this spectrum display in a series of waterfalls stacked on
top of each other. I purchased one of the 100MHz full SDR &
antenna, and then a 16MHz digitizer set, less antenna. I also have a
64MHz oscillator that I can put in place of the socketed 100MHz oscillator,
so I can test the boards at that lower rate.
<br class=""><br class=""></blockquote>----------------------snip--------------</font><font size="+1" face="Comic Sans MS" class=""> </font><pre class="moz-signature" cols="72"><font size="+1" face="Comic Sans MS" class="">--
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~~~******************* Alex Fraser *******************~~~
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</font></pre><font size="+1" face="Comic Sans MS" class=""></font><br class=""><br class="">_______________________________________________<br class="">Tacos
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