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ben-wpan/usrp/sps/viz
Werner Almesberger fd27bdc442 usrp/sps/: spectrum scan utilities (work in progress)
- collect: set up a test transmission at each available frequency, then
  then record the signal seen by the USRP2
- norm: extract parameters necessary for normalization
- viz: visualize the spectrum with gnuplot
- row: generate rows of spectra with "viz"
2011-03-03 23:26:31 -03:00

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#!/bin/sh
usage()
{
echo "usage: $0 [-f font] prefix frequency" 1>&2
exit 1
}
font=
term=
output=
while true; do
case "$1" in
-f) [ "$2" ] || usage
shift
font=$1
shift;;
-p) [ "$2" ] || usage
shift
term="set term png"
output="set output \"$1\""
shift;;
*)
break;;
esac
done
[ "$2" ] || usage
[ "$3" ] && usage
prefix=$1
f=$2
../fft -s 100 -d -w hamming 100 <./$prefix-$f >_tmp
set `./norm _tmp`
xm=$1.0 # sample number of y peak
ym=$2 # magnitude of y peak
n=$3 # total number of samples
span=6.25 # ADC sample rate in MHz / decimation (100 MHz/16)
gnuplot -persist <<EOF
$term
$output
set label "$prefix" at graph 0.03, graph 0.93 font "$font,22"
set label sprintf("+%.1f dB", $ym) at graph 0.03, graph 0.82 font "$font,18"
set label sprintf("%.1f MHz", $f-0.5) \
at graph 0.97, graph 0.93 right font "$font,22"
set label sprintf("+%.1f ppm", (($xm/$n-0.5)*$span+0.5)/($f-0.5)*1000000) \
at graph 0.97, graph 0.82 right font "$font,18"
set xrange [-2.5:2.5]
set yrange [-70:0]
set mxtics 10
set mytics 2
set grid
set xlabel "MHz from nominal frequency of test wave"
set style fill solid 1
plot "_tmp" using ((\$0/$n-0.5)*$span+0.5):(\$1-$ym) with lines notitle, \
"<echo -0.9 -$ym 0.2" with boxes notitle
EOF
rm -f _tmp