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.. | ||
README.md | ||
dft_detect.c | ||
plot_fft_pow.py | ||
plot_fft_simple.py | ||
reset_usb.c | ||
rs_detect.c | ||
rtlsdr_scan.pl | ||
scan_fft_pow.c | ||
scan_fft_simple.c | ||
scan_multi.sh | ||
scan_multi_rs.pl |
README.md
detect radiosonde type
Files
dft_detect.c
Compile
gcc dft_detect.c -lm -o dft_detect
Usage
./dft_detect [options] <file>
options:
--IQ <fq>
: IQ data input, where <fq>
is the relative frequency in -0.5..0.5
-v
: sample count
-c
: continuous output
-t <sec>
: time limit
(input <file>
can be stdin
)
FM data:
./dft_detect <fm_audio.wav>
IQ data:
./dft_detect --IQ <fq> <iq_data.wav>
For IQ data (i.e. 2 channels) it is possible to read raw data (without wav header):
./dft_detect --IQ <fq> - <sr> <bs> <iq_data.raw>
where
<sr>
: sample rate
<bs>=8,16,32
: bits per (real) sample (u8, s16 or f32)
dft_detect
stops, if a (potential) radiosonde signal is detected, or if a time limit is set with option -t
.
With option -c
detection is continued, but a time limit can be set with -t
.
Output is of the form <TYPE>: <score>
where the correlation score is a normalized value in -1..+1
.
Examples
Ex.1
$ ./dft_detect fm_audio.wav
sample_rate: 48000
bits : 8
channels : 1
RS41: 0.9885
Ex.2
$ ./dft_detect -c fm_audio.wav 2>/dev/null
RS41: 0.9885
RS41: 0.9851
RS41: 0.9784
RS41: 0.9869
RS41: 0.9845
RS41: 0.9828
RS41: 0.9814
RS41: 0.9821
RS41: 0.9823
RS41: 0.9882
[...]
Ex.3
$ ./dft_detect -c -t 4 fm_audio.wav 2>/dev/null
RS41: 0.9885
RS41: 0.9851
RS41: 0.9784
RS41: 0.9869
RS41: 0.9845
Ex.4
$ ./dft_detect -v -c -t 2 fm_audio.wav 2>/dev/null
sample: 39801
RS41: 0.9885
sample: 87824
RS41: 0.9851
sample: 135831
RS41: 0.9784
Ex.5
Some radiosonde types have similar signals, false detection is possible.
$ ./dft_detect -c -t 4 fm_meisei.wav 2>/dev/null
MEISEI: 0.9802
MRZ: -0.9720
MEISEI: 0.9829
Here a Meisei radiosonde seems to be more likely.
Ex.6
Confirmed detection (two hits):
$ ./dft_detect -d2 -t 4 fm_meisei.wav 2>/dev/null
MEISEI: 0.9829