Updates to User Guide.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8049 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
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Joe Taylor 2017-08-30 17:06:49 +00:00
parent c6c0c33be0
commit 244d2291eb

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@ -9,33 +9,25 @@ When an operator decides to answer a CQ, he already knows his own
callsign and that of his potential QSO partner. He therefore knows
what to expect for at least 56 of the 72 message bits in a
standard-format response to his call. The _WSJT-X_ decoders for QRA64
and FT8 can use these AP bits to decode messages containing them with
higher sensitivity than otherwise possible.
and FT8 can use these and similar AP bits to decode messages
containing them with higher sensitivity than otherwise possible.
We have implemented AP decoding in slightly different ways in QRA64
and FT8. To provide some explicit examples for users, we provide here
a brief description of the FT8 behavior.
The FT8 decoder always tries first to decode a signal without using
any AP information. If this attempt fails, and if *Enable AP* is
checked on the *Decode* menu, a second attempt hypothesizes that the
message contains callsigns MyCall and DxCall. If the QSO has
progressed to the point where signal reports have been exchanged, a
third attempt hypothesizes that the message contains the known
callsigns followed by RRR, RR73, or 73.
AP decoding attempts effectively set the AP bits to the hypothesized
values, as if they had been received perfectly. The decoder then
values, as if they had been received correctly. The decoder then
proceeds to determine whether the remaining message and parity bits
are consistent with the hypothesized AP bits. If a codeword is found
that the decoder judges to have high (but not overwhelmingly high)
probability of being correct, a ? character is appended when the
decoded message is displayed. Decodes thus marked are not sent to
{pskreporter} to avoid occasional misleading spots of false decodes.
decoded message is displayed. To avoid misleading spots of occasional
false decodes, messages so marked are not forwarded to {pskreporter}.
Successful AP decodes are always labeled with an end-of-line indicator
of the form aP, where P is one of the single-digit AP decoding types
listed in Table 1. For example, an a2 designator says that the
listed in Table 1. For example, an `a2` designator says that the
successful decode used MyCall as hypothetically known information.
[[AP_INFO_TABLE]]
@ -51,6 +43,23 @@ successful decode used MyCall as hypothetically known information.
|6 | MyCall DxCall RR73
|===============================================
Table 2 lists the six possible QSO states that are tracked by the
WSJT-X auto-sequencer, along with the type of AP decoding that would
be attempted in each state.
[[AP decoding types for each QSO state]]
[width="35%",cols="h10,<m20",frame=topbot,options="header"]
|===========================================
|State |AP type
|CALLING | 1, 2
|REPLYING | 2, 3
|REPORT | 2, 3
|ROGER_REPORT | 3, 4, 5, 6
|ROGERS | 3, 4, 5, 6
|SIGNOFF | 3, 1, 2
|===========================================
=== Decoded Lines
Displayed information accompanying decoded messages generally includes UTC,