IRA/ira_waterfall.html at master · patchvonbraun/IRA · GitHub

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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	<META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=utf-8">
	<TITLE></TITLE>
	<META NAME="GENERATOR" CONTENT="OpenOffice.org 2.3  (Linux)">
	<META NAME="AUTHOR" CONTENT="Marcus Leech">
	<META NAME="CREATED" CONTENT="20090317;19333200">
	<META NAME="CHANGEDBY" CONTENT="Marcus Leech">
	<META NAME="CHANGED" CONTENT="20090317;20192700">
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<BODY LANG="en-US" DIR="LTR">
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>IRA
Waterfall Window</FONT></FONT></P>
<P>The IRA Waterfall windows shows a high-resolution spectrum using a
technique known as a “waterfall” display. Each line of pixels in
the display shows one seconds worth of spectrum, with relative powers
shown as colors, using a color gradient.</P>
<P><IMG SRC="ira_waterfall.png" NAME="graphics1" ALIGN=LEFT WIDTH=1032 HEIGHT=536 BORDER=0><BR CLEAR=LEFT><BR><BR>
</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>The
Waterfall Segment Control</I></FONT></FONT></P>
<P STYLE="font-style: normal">This control allows you to choose which
segment of the SETI spectrum you wish to display—the SETI spectrum
has as many bins as the selected bandwidth, so it would be impossible
to display it all at once. Move the slider to select a coarse
segment, then use the <I>Fine Segment Control </I>to fine-tune the
display.</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>The
Dynamic Range Indicators</I></FONT></FONT></P>
<P>Immediately above the <I>Fine Segment Control</I> slider, there
are 3 text areas that show the minimum and maximum data values in the
displayed waterfall segment, as well as the ratio between these two
numbers, in dB.</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>The
Frequency Indicators</I></FONT></FONT></P>
<P STYLE="font-style: normal">Above the waterfall display, there are
3 frequency indicators that indicate the frequency range shown in the
waterfall display, with the lowest on the left, the highest on the
right, and the middle value, in the middle.</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>Mark
RFI Control</I></FONT></FONT></P>
<P STYLE="font-style: normal">The Mark RFI control allows you to
visually determine those sets of waterfall bins that the SETI
analyser has determined constitute RFI. This is done by marking those
bins with alternating lines of red and dark blue.</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>Brightness
Control</I></FONT></FONT></P>
<P STYLE="font-style: normal">The Brightness control determines the
color gradient used to represent relative power values in the
waterfall display. Available choices are 100, 75, 66, and 50 percent
brightness. It is often useful to reduce the brightness for waterfall
segments that have a low dynamic range, otherwise, they appear to be
misleadingly bright.</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>The
Color Gradient Display</I></FONT></FONT></P>
<P STYLE="font-style: normal">This display shows the color gradient
currently in use, with the corresponding relative power levels, in
dB, shown at each end of the gradient display.</P>
<P STYLE="margin-top: 0.17in; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4><I>The
Export Waterfall control</I></FONT></FONT></P>
<P STYLE="font-style: normal">This control allows you to export the
current waterfall display as an X Pixmap (XPM) file. It will pop-up a
file browser, allowing you to specify the filename and directory for
the export XPM file.</P>
<P><I>DISMISS</I></P>
<P STYLE="font-style: normal">This control causes the Waterfall
window to close, but waterfall data will continue to be updated.</P>
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