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71 lines
3.2 KiB
Plaintext
Executable File
71 lines
3.2 KiB
Plaintext
Executable File
wsprd is a decoder for K1JT's Weak Signal Propagation Reporter (WSPR) mode.
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The program is written in C and is a command-line program that reads from a
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.c2 file or .wav file and writes output to the console. It is used by WSJT-X
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for wspr-mode decoding.
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USAGE:
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wsprd [options...] infile
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OPTIONS:
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-a <path> path to writeable data files, default="."
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-B disable block demodulation - use single-symbol noncoherent demod
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-c write .c2 file at the end of the first pass
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-C maximum number of decoder cycles per bit, default 10000
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-d deeper search. Slower, a few more decodes
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-e x (x is transceiver dial frequency error in Hz)
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-f x (x is transceiver dial frequency in MHz)
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-H do not use (or update) the hash table
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-J use the stack decoder instead of Fano decoder
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-m decode wspr-15 .wav file
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-o n (0<=n<=5), decoding depth for OSD, default is disabled
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-q quick mode - doesn't dig deep for weak signals
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-s single pass mode, no subtraction (same as original wsprd)
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-v verbose mode (shows dupes)
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-w wideband mode - decode signals within +/- 150 Hz of center
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-z x (x is fano metric table bias, default is 0.45)
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infile can be either .wav or .c2
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e.g.
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./wsprd -wf 14.0956 140709_2258.wav
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Note that for .c2 files, the frequency within the file overrides the command
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line value.
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FEATURES:
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By default, wsprd reports signals that are within +/- 110 Hz of the
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subband center frequency. The wideband option (-w) extends this to +/- 150 Hz.
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wsprd maintains a hashtable and will decode all three types of wspr
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messages. An option (-H) is available to turn off use of the hashtable.
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Decoding is attempted using soft symbols derived using single-symbol
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noncoherent detection. If decoding fails, then soft symbols derived using
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block demodulation over 2- and 3-symbol blocks are used in subsequent
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decoding attempts. For slower computers, block demodulation can be
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disabled with the -B command line option.
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The symbols are decoded using Phil Karn's sequential decoder routine,
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fano.c. The -J option replaces the Fano algorithm with the Jelinek
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"stack-bucket" algorithm. If the -o command line option is enabled, then
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an ordered-statistics decoder (OSD) is invoked if the Fano (or Jelinek) algorithm
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fails. The OSD is a complete decoder, meaning that it always returns a codeword.
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A returned codeword is considered valid only if the unpacked decode contains
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a callsign that is already in the hashtable.
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NOTES:
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This program attempts to maximize the number of successful decodes per transmit
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interval by trying to decode virtually every peak in the averaged spectrum.
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The program also implements two-pass decoding, whereby signals that are successfully
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decoded are subtracted one-by-one during the first decoding pass. Then, the
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decoder is run again. In many cases the subtraction process will uncover signals
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that can then be successfully decoded on the second pass.
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There will be occasional duplicate decodes when two closely spaced
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peaks come from the same signal. The program removes dupes based on callsign
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and frequency. Two decodes that have the same callsign and estimated frequencies
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that are within 1 Hz will be treated as decodes of the same signal. This
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dupechecking is turned off with the -v flag.
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