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				| @ -22,7 +22,6 @@ set (UG_SRCS | ||||
|   controls-functions-status-bar.adoc | ||||
|   controls-functions-wide-graph.adoc | ||||
|   cooperating-programs.adoc | ||||
|   decoded_lines.adoc | ||||
|   faq.adoc | ||||
|   font-sizes.adoc | ||||
|   install-from-source.adoc | ||||
| @ -34,6 +33,7 @@ set (UG_SRCS | ||||
|   logging.adoc | ||||
|   make-qso.adoc | ||||
|   new_features.adoc | ||||
|   odds_and_ends.adoc | ||||
|   platform-dependencies.adoc | ||||
|   protocols.adoc | ||||
|   settings-advanced.adoc | ||||
|  | ||||
| @ -1,3 +1,5 @@ | ||||
| === Decoded Lines | ||||
| 
 | ||||
| Displayed information accompanying decoded messages generally includes UTC, | ||||
| signal-to-noise ratio in dB, time offset DT in seconds, and | ||||
| audio frequency in Hz.  Some modes include additional information such | ||||
| @ -33,4 +35,4 @@ End of line information:: | ||||
|  `R` - QRA64 _a priori_ return code + | ||||
|  `T` - Length of analyzed region (s) | ||||
| 
 | ||||
| 
 | ||||
| === Reference Spectrum | ||||
| @ -3,22 +3,50 @@ | ||||
| 
 | ||||
| All QSO modes except ISCAT use structured messages that compress | ||||
| user-readable information into fixed-length packets of exactly 72 | ||||
| bits.  Each message consists of two 28-bit fields for callsigns and a | ||||
| 15-bit field for a grid locator, report, acknowledgment, or a "`73`" | ||||
| sign-off indicator.  A 72^nd^ bit flags a message containing arbitrary | ||||
| alphanumeric text, up to 13 characters.  Special cases allow other | ||||
| information such as add-on callsign prefixes (e.g., ZA/K1ABC) or | ||||
| suffixes (e.g., K1ABC/4) to be encoded. The basic aim is to compress | ||||
| bits.  Each message consists of two 28-bit fields normally used for | ||||
| callsigns and a 15-bit field for a grid locator, report, | ||||
| acknowledgment, or 73.  An additional bit flags a message containing | ||||
| arbitrary alphanumeric text, up to 13 characters.  Special cases allow | ||||
| other information such as add-on callsign prefixes (e.g., ZA/K1ABC) or | ||||
| suffixes (e.g., K1ABC/P) to be encoded. The basic aim is to compress | ||||
| the most common messages used for minimally valid QSOs into a fixed | ||||
| 72-bit length.  To be useful on channels with low signal-to-noise | ||||
| ratio, this kind of lossless compression requires use of a strong | ||||
| forward error correcting (FEC) code.  Different codes are used for | ||||
| each mode.  Accurate synchronization of time and frequency is required | ||||
| between transmitting and receiving stations.  As an aid to the | ||||
| decoders, each protocol includes a "`sync vector`" of known symbols | ||||
| interspersed with the information-carrying symbols.  Generated | ||||
| waveforms for all of the _WSJT-X_ modes have continuous phase and  | ||||
| constant envelope. | ||||
| 72-bit length. | ||||
| 
 | ||||
| A standard amateur callsign consists of a one- or two-character | ||||
| prefix, at least one of which must be a letter, followed by a digit | ||||
| and a suffix of one to three letters. Within these rules, the number | ||||
| of possible callsigns is equal to 37×36×10×27×27×27, or somewhat over | ||||
| 262 million. (The numbers 27 and 37 arise because in the first and | ||||
| last three positions a character may be absent, or a letter, or | ||||
| perhaps a digit.) Since 2^28^ is more than 268 million, 28 bits are | ||||
| enough to encode any standard callsign uniquely. Similarly, the number | ||||
| of 4-digit Maidenhead grid locators on earth is 180×180 = 32,400, | ||||
| which is less than 2^15^ = 32,768; so a grid locator requires 15 bits. | ||||
| 
 | ||||
| Some 6 million of the possible 28-bit values are not needed for | ||||
| callsigns.  A few of these slots have been assigned to special message | ||||
| components such as CQ, CQ DX, DE, and QRZ. CQ may be followed by three | ||||
| digits to indicate a desired callback frequency. (If K1ABC transmits | ||||
| on a standard calling frequency, say 50.280, and sends "`CQ 290 K1ABC | ||||
| FN42`", it means that s/he will listen on 50.290 and respond there to | ||||
| any replies.) A numerical signal report of the form "`–NN`" or | ||||
| "`R–NN`" can be sent in place of a grid locator.  (As originally | ||||
| defined, numerical signal reports were required to fall between -01 | ||||
| and -30 dB.  Recent program versions accommodate reports between | ||||
| -50 and +49 dB.) A country prefix or portable suffix may be | ||||
| attached to one of the callsigns.  When this feature is used the | ||||
| additional information is sent in place of the grid locator or by | ||||
| encoding additional information into some of the 6 million available | ||||
| slots mentioned above.   | ||||
| 
 | ||||
| To be useful on channels with low signal-to-noise ratio, this kind of | ||||
| lossless message compression requires use of a strong forward error | ||||
| correcting (FEC) code.  Different codes are used for each mode. | ||||
| Accurate synchronization of time and frequency is required between | ||||
| transmitting and receiving stations.  As an aid to the decoders, each | ||||
| protocol includes a "`sync vector`" of known symbols interspersed with | ||||
| the information-carrying symbols.  Generated waveforms for all of the | ||||
| _WSJT-X_ modes have continuous phase and constant envelope. | ||||
| 
 | ||||
| [[SLOW_MODES]] | ||||
| === Slow Modes | ||||
|  | ||||
| @ -145,10 +145,6 @@ include::vhf-features.adoc[] | ||||
| == WSPR Mode | ||||
| include::wspr.adoc[] | ||||
| 
 | ||||
| [[DECODED_LINES]] | ||||
| == Decoded Lines | ||||
| include::decoded_lines.adoc[] | ||||
| 
 | ||||
| [[COMMAND_REF]] | ||||
| == On-Screen Controls | ||||
| 
 | ||||
| @ -184,6 +180,10 @@ include::controls-functions-wide-graph.adoc[] | ||||
| == Logging | ||||
| include::logging.adoc[] | ||||
| 
 | ||||
| [[ODDS_AND_ENDS]] | ||||
| == Odds and Ends | ||||
| include::odds_and_ends.adoc[] | ||||
| 
 | ||||
| [[COOP_PGMS]] | ||||
| == Cooperating Programs | ||||
| include::cooperating-programs.adoc[] | ||||
|  | ||||
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