GNU Radio Companion 3.7.10
gnuradio-companion elf_vlf.grc
Generating a file with pulse spacing in hertz as example, 8 Hz, 8 Hz, 10 Hz, 10 Hz
printf "\x08\x08\x10\x10" > byte.bin
or in double format as example, 9.8 Hz, 10 Hz, 7.83 Hz
python3 -c 'from struct import pack; f=open("double.bin", "wb"); f.write(pack("d", 9.80) + pack("d", 10) + pack("d", 7.83))'
Encode data into wav file, where f - carrier frequency, s - sample rate, c - number of pulsations at the carrier frequency, r - read format
./interval_coding.py double.bin -f 501 -s 80000 -c 32 -t 1 -r double
./interval_coding.py byte.bin -f 501 -s 80000 -c 4 -t 1 -r byte
Using frequencies from keyboard input
./interval_coding.py "7.83 10 7.83 10" -f 501 -s 80000 -c 23 -t 1