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r8020 | k9an | 2017-08-10 03:51:25 +0100 (Thu, 10 Aug 2017) | 1 line

Correct misspelling. Thanks Seb, W4AS.
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r8021 | bsomervi | 2017-08-10 19:07:53 +0100 (Thu, 10 Aug 2017) | 1 line

Fix FT8 encoding description
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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx-1.8@8025 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Bill Somerville 2017-08-13 23:37:16 +00:00
parent 02134c61e0
commit 0415103f16
2 changed files with 9 additions and 9 deletions
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2
Configuration.ui
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@ -1820,7 +1820,7 @@ for assessing propagation and system performance.</string>
<item>
<widget class="QGroupBox" name="groupBox_3">
<property name="toolTip">
<string>See WSPR documentattion Appendix C for details of how to determine these factors for your radio.</string>
<string>See WSPR documentation Appendix C for details of how to determine these factors for your radio.</string>
</property>
<property name="title">
<string>Frequency Calibration</string>

16
doc/user_guide/en/protocols.adoc
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@ -61,15 +61,15 @@ _WSJT-X_ modes have continuous phase and constant envelope.
[[FT8PRO]]
==== FT8
Forward error correction (FEC) in FT8 uses a low-density
parity check (LDPC) code with 75 information bits, a 12-bit cyclic
redundancy check (CRC), and 174 channel symbols. It is thus called an
LDPC (174,87) code. Synchronization uses 7×7 Costas arrays at the
beginning, middle, and end of each transmission. Modulation is 8-tone
frequency-shift keying (8-FSK) at 12000/1920 = 6.25 baud. Each
Forward error correction (FEC) in FT8 uses a low-density parity check
(LDPC) code with 75 information bits, a 12-bit cyclic redundancy check
(CRC), and 87 parity bits making a 174-bit codeword. It is thus
called an LDPC (174,87) code. Synchronization uses 7×7 Costas arrays
at the beginning, middle, and end of each transmission. Modulation is
8-tone frequency-shift keying (8-FSK) at 12000/1920 = 6.25 baud. Each
transmitted symbol carries three bits, so the total number of channel
symbols is 174/3 + 21 = 79. The total occupied bandwidth is
8 × 6.25 = 50 Hz.
symbols is 174/3 + 21 = 79. The total occupied bandwidth is 8 × 6.25
= 50 Hz.
[[JT4PRO]]
==== JT4