Merged master 8748
This commit is contained in:
Jordan Sherer
@@ -1,12 +0,0 @@
|
||||
#!/bin/sh
|
||||
|
||||
# Run all the examples, and check the output against the corresponding -out
|
||||
# file. Note that slight differences are possible when the examples are
|
||||
# run on different machines, due to slightly different round-off errors.
|
||||
|
||||
for e in `ls ex-* | grep -v "\\." | grep -v .-out`
|
||||
do
|
||||
echo Running $e:
|
||||
$e 2>&1 | diff ${e}-out -
|
||||
echo " "
|
||||
done
|
||||
@@ -1,153 +0,0 @@
|
||||
/*
|
||||
#Sov Mil Order of Malta: 15: 28: EU: 41.90: -12.43: -1.0: 1A:
|
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#1A;
|
||||
#Spratly Islands: 26: 50: AS: 9.88: -114.23: -8.0: 1S:
|
||||
#1S,9M0,BV9S;
|
||||
#Monaco: 14: 27: EU: 43.73: -7.40: -1.0: 3A:
|
||||
#3A;
|
||||
#Heard Island: 39: 68: AF: -53.08: -73.50: -5.0: VK0H:
|
||||
#=VK0IR;
|
||||
#Macquarie Island: 30: 60: OC: -54.60: -158.88: -10.0: VK0M:
|
||||
#=VK0KEV;
|
||||
#Cocos-Keeling: 29: 54: OC: -12.15: -96.82: -6.5: VK9C:
|
||||
#AX9C,AX9Y,VH9C,VH9Y,VI9C,VI9Y,VJ9C,VJ9Y,VK9C,VK9Y,VL9C,VL9Y,VM9C,VM9Y,
|
||||
#VN9C,VN9Y,VZ9C,VZ9Y,=VK9AA;
|
||||
*/
|
||||
|
||||
|
||||
#include "countrydat.h"
|
||||
#include <QFile>
|
||||
#include <QTextStream>
|
||||
|
||||
|
||||
void CountryDat::init(const QString filename)
|
||||
{
|
||||
_filename = filename;
|
||||
_data.clear();
|
||||
}
|
||||
|
||||
QString CountryDat::_extractName(const QString line) const
|
||||
{
|
||||
int s1 = line.indexOf(':');
|
||||
if (s1>=0)
|
||||
{
|
||||
QString name = line.mid(0,s1);
|
||||
return name;
|
||||
}
|
||||
return "";
|
||||
}
|
||||
|
||||
void CountryDat::_removeBrackets(QString &line, const QString a, const QString b) const
|
||||
{
|
||||
int s1 = line.indexOf(a);
|
||||
while (s1 >= 0)
|
||||
{
|
||||
int s2 = line.indexOf(b);
|
||||
line = line.mid(0,s1) + line.mid(s2+1,-1);
|
||||
s1 = line.indexOf(a);
|
||||
}
|
||||
}
|
||||
|
||||
QStringList CountryDat::_extractPrefix(QString &line, bool &more) const
|
||||
{
|
||||
line = line.remove(" \n");
|
||||
line = line.replace(" ","");
|
||||
|
||||
_removeBrackets(line,"(",")");
|
||||
_removeBrackets(line,"[","]");
|
||||
_removeBrackets(line,"<",">");
|
||||
_removeBrackets(line,"~","~");
|
||||
|
||||
int s1 = line.indexOf(';');
|
||||
more = true;
|
||||
if (s1 >= 0)
|
||||
{
|
||||
line = line.mid(0,s1);
|
||||
more = false;
|
||||
}
|
||||
|
||||
QStringList r = line.split(',');
|
||||
|
||||
return r;
|
||||
}
|
||||
|
||||
|
||||
void CountryDat::load()
|
||||
{
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||||
_data.clear();
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||||
_countryNames.clear(); //used by countriesWorked
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|
||||
QFile inputFile(_filename);
|
||||
if (inputFile.open(QIODevice::ReadOnly))
|
||||
{
|
||||
QTextStream in(&inputFile);
|
||||
while ( !in.atEnd() )
|
||||
{
|
||||
QString line1 = in.readLine();
|
||||
if ( !in.atEnd() )
|
||||
{
|
||||
QString line2 = in.readLine();
|
||||
|
||||
QString name = _extractName(line1);
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if (name.length()>0)
|
||||
{
|
||||
_countryNames << name;
|
||||
bool more = true;
|
||||
QStringList prefixs;
|
||||
while (more)
|
||||
{
|
||||
QStringList p = _extractPrefix(line2,more);
|
||||
prefixs += p;
|
||||
if (more)
|
||||
line2 = in.readLine();
|
||||
}
|
||||
|
||||
QString p;
|
||||
foreach(p,prefixs)
|
||||
{
|
||||
if (p.length() > 0)
|
||||
_data.insert(p,name);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
inputFile.close();
|
||||
}
|
||||
}
|
||||
|
||||
// return country name else ""
|
||||
QString CountryDat::find(QString call) const
|
||||
{
|
||||
call = call.toUpper ();
|
||||
|
||||
// check for exact match first
|
||||
if (_data.contains ("=" + call))
|
||||
{
|
||||
return fixup (_data.value ("=" + call), call);
|
||||
}
|
||||
|
||||
auto prefix = call;
|
||||
while (prefix.size () >= 1)
|
||||
{
|
||||
if (_data.contains (prefix))
|
||||
{
|
||||
return fixup (_data.value (prefix), call);
|
||||
}
|
||||
prefix = prefix.left (prefix.size () - 1);
|
||||
}
|
||||
return QString {};
|
||||
}
|
||||
|
||||
QString CountryDat::fixup (QString country, QString const& call) const
|
||||
{
|
||||
//
|
||||
// deal with special rules that cty.dat does not cope with
|
||||
//
|
||||
|
||||
// KG4 2x1 and 2x3 calls that map to Gitmo are mainland US not Gitmo
|
||||
if (call.startsWith ("KG4") && call.size () != 5)
|
||||
{
|
||||
country.replace ("Guantanamo Bay", "United States");
|
||||
}
|
||||
return country;
|
||||
}
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||||
File diff suppressed because it is too large
Load Diff
@@ -0,0 +1,384 @@
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||||
[[PROTOCOL_OVERVIEW]]
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||||
=== Overview
|
||||
|
||||
All QSO modes except ISCAT use structured messages that compress
|
||||
user-readable information into fixed-length packets of 72 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. The
|
||||
information payload in FT8 includes 3 additional bits (75 bits total).
|
||||
One of the added bits is used to flag special messages used by the
|
||||
DXpedition station in FT8 DXpedition Mode. Uses for the remaining two
|
||||
bits are yet to be defined.
|
||||
|
||||
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`, `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 `nn` 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.
|
||||
|
||||
As a convenience for sending directed CQ messages, the compression
|
||||
algorithm supports messages starting with `CQ AA` through `CQ ZZ`.
|
||||
These message fragments are encoded internally as if they were the
|
||||
callsigns `E9AA` through `E9ZZ`. Upon reception they are converted
|
||||
back to the form `CQ AA` through `CQ ZZ`, for display to the user.
|
||||
|
||||
The FT8 and MSK144 modes support a special feature allowing convenient
|
||||
transmission and acknowledgment of four-character grid locators, the
|
||||
required exchanges in most North American VHF contests. With this
|
||||
Contest Mode enabled, _WSJT-X_ supports messages of the form `W9XYZ
|
||||
K1ABC R FN42` by converting the grid locator to that of its
|
||||
diametrically opposite point on Earth. The receiving program
|
||||
recognizes a locator implying a distance greater than 10,000 km, does
|
||||
the reverse transformation, and inserts the implied "`R`". Obviously,
|
||||
this mode should not be used on the HF bands or under other
|
||||
circumstances where world-wide propagation is possible.
|
||||
|
||||
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
|
||||
|
||||
[[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 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.
|
||||
|
||||
[[JT4PRO]]
|
||||
==== JT4
|
||||
|
||||
FEC in JT4 uses a strong convolutional code with constraint length
|
||||
K=32, rate r=1/2, and a zero tail. This choice leads to an encoded
|
||||
message length of (72+31) x 2 = 206 information-carrying bits.
|
||||
Modulation is 4-tone frequency-shift keying (4-FSK) at 11025 / 2520 =
|
||||
4.375 baud. Each symbol carries one information bit (the most
|
||||
significant bit) and one synchronizing bit. The two 32-bit
|
||||
polynomials used for convolutional encoding have hexadecimal values
|
||||
0xf2d05351 and 0xe4613c47, and the ordering of encoded bits is
|
||||
scrambled by an interleaver. The pseudo-random sync vector is the
|
||||
following sequence (60 bits per line):
|
||||
|
||||
000011000110110010100000001100000000000010110110101111101000
|
||||
100100111110001010001111011001000110101010101111101010110101
|
||||
011100101101111000011011000111011101110010001101100100011111
|
||||
10011000011000101101111010
|
||||
|
||||
|
||||
[[JT9PRO]]
|
||||
==== JT9
|
||||
|
||||
FEC in JT9 uses the same strong convolutional code as JT4: constraint
|
||||
length K=32, rate r=1/2, and a zero tail, leading to an encoded
|
||||
message length of (72+31) × 2 = 206 information-carrying
|
||||
bits. Modulation is nine-tone frequency-shift keying, 9-FSK at
|
||||
12000.0/6912 = 1.736 baud. Eight tones are used for data, one for
|
||||
synchronization. Eight data tones means that three data bits are
|
||||
conveyed by each transmitted information symbol. Sixteen symbol
|
||||
intervals are devoted to synchronization, so a transmission requires a
|
||||
total of 206 / 3 + 16 = 85 (rounded up) channel symbols. The sync
|
||||
symbols are those numbered 1, 2, 5, 10, 16, 23, 33, 35, 51, 52, 55,
|
||||
60, 66, 73, 83, and 85 in the transmitted sequence. Tone spacing of
|
||||
the 9-FSK modulation for JT9A is equal to the keying rate, 1.736 Hz.
|
||||
The total occupied bandwidth is 9 × 1.736 = 15.6 Hz.
|
||||
|
||||
[[JT65PRO]]
|
||||
==== JT65
|
||||
|
||||
A detailed description of the JT65 protocol was published in
|
||||
{jt65protocol} for September-October, 2005. A Reed Solomon (63,12)
|
||||
error-control code converts 72-bit user messages into sequences of 63
|
||||
six-bit information-carrying symbols. These are interleaved with
|
||||
another 63 symbols of synchronizing information according to the
|
||||
following pseudo-random sequence:
|
||||
|
||||
100110001111110101000101100100011100111101101111000110101011001
|
||||
101010100100000011000000011010010110101010011001001000011111111
|
||||
|
||||
|
||||
The synchronizing tone is normally sent in each interval having a
|
||||
"`1`" in the sequence. Modulation is 65-FSK at 11025/4096 = 2.692
|
||||
baud. Frequency spacing between tones is equal to the keying rate for
|
||||
JT65A, and 2 and 4 times larger for JT65B and JT65C. For EME QSOs the
|
||||
signal report OOO is sometimes used instead of numerical signal
|
||||
reports. It is conveyed by reversing sync and data positions in the
|
||||
transmitted sequence. Shorthand messages for RO, RRR, and 73 dispense
|
||||
with the sync vector entirely and use time intervals of 16384/11025 =
|
||||
1.486 s for pairs of alternating tones. The lower frequency is the
|
||||
same as that of the sync tone used in long messages, and the frequency
|
||||
separation is 110250/4096 = 26.92 Hz multiplied by n for JT65A, with n
|
||||
= 2, 3, 4 used to convey the messages RO, RRR, and 73.
|
||||
|
||||
[[QRA64_PROTOCOL]]
|
||||
==== QRA64
|
||||
|
||||
QRA64 is intended for EME and other extreme weak-signal applications.
|
||||
Its internal code was designed by IV3NWV. The protocol uses a (63,12)
|
||||
**Q**-ary **R**epeat **A**ccumulate code that is inherently better
|
||||
than the Reed Solomon (63,12) code used in JT65, yielding a 1.3 dB
|
||||
advantage. A new synchronizing scheme is based on three 7 x 7 Costas
|
||||
arrays. This change yields another 1.9 dB advantage.
|
||||
|
||||
In most respects the current implementation of QRA64 is operationally
|
||||
similar to JT65. QRA64 does not use two-tone shorthand messages, and
|
||||
it makes no use of a callsign database. Rather, additional
|
||||
sensitivity is gained by making use of already known information as a
|
||||
QSO progresses -- for example, when reports are being exchanged and
|
||||
you have already decoded both callsigns in a previous transmission.
|
||||
QRA64 presently offers no message averaging capability, though that
|
||||
feature may be added. In early tests, many EME QSOs were made using
|
||||
submodes QRA64A-E on bands from 144 MHz to 24 GHz.
|
||||
|
||||
[[WSPR_PROTOCOL]]
|
||||
==== WSPR
|
||||
|
||||
WSPR is designed for probing potential radio propagation paths using
|
||||
low power beacon-like transmissions. WSPR signals convey a callsign,
|
||||
Maidenhead grid locator, and power level using a compressed data
|
||||
format with strong forward error correction and narrow-band 4-FSK
|
||||
modulation. The protocol is effective at signal-to-noise ratios as low
|
||||
as –31 dB in a 2500 Hz bandwidth.
|
||||
|
||||
WSPR messages can have one of three possible formats illustrated by
|
||||
the following examples:
|
||||
|
||||
- Type 1: K1ABC FN42 37
|
||||
- Type 2: PJ4/K1ABC 37
|
||||
- Type 3: <PJ4/K1ABC> FK52UD 37
|
||||
|
||||
Type 1 messages contain a standard callsign, a 4-character Maidenhead
|
||||
grid locator, and power level in dBm. Type 2 messages omit the grid
|
||||
locator but include a compound callsign, while type 3 messages replace
|
||||
the callsign with a 15-bit hash code and include a 6-character locator
|
||||
as well as the power level. Lossless compression techniques squeeze
|
||||
all three message types into exactly 50 bits of user
|
||||
information. Standard callsigns require 28 bits and 4-character grid
|
||||
locators 15 bits. In Type 1 messages, the remaining 7 bits convey the
|
||||
power level. In message types 2 and 3 these 7 bits convey power level
|
||||
along with an extension or re-definition of fields normally used for
|
||||
callsign and locator. Together, these compression techniques amount to
|
||||
“source encoding” the user message into the smallest possible number
|
||||
of bits.
|
||||
|
||||
WSPR uses a convolutional code with constraint length K=32 and rate
|
||||
r=1/2. Convolution extends the 50 user bits into a total of (50 + K –
|
||||
1) × 2 = 162 one-bit symbols. Interleaving is applied to scramble the
|
||||
order of these symbols, thereby minimizing the effect of short bursts
|
||||
of errors in reception that might be caused by fading or interference.
|
||||
The data symbols are combined with an equal number of synchronizing
|
||||
symbols, a pseudo-random pattern of 0’s and 1’s. The 2-bit
|
||||
combination for each symbol is the quantity that determines which of
|
||||
four possible tones to transmit in any particular symbol
|
||||
interval. Data information is taken as the most significant bit, sync
|
||||
information the least significant. Thus, on a 0 – 3 scale, the tone
|
||||
for a given symbol is twice the value (0 or 1) of the data bit, plus
|
||||
the sync bit.
|
||||
|
||||
[[SLOW_SUMMARY]]
|
||||
==== Summary
|
||||
|
||||
Table 2 provides a brief summary parameters for the slow modes in
|
||||
_WSJT-X_. Parameters K and r specify the constraint length and rate
|
||||
of the convolutional codes; n and k specify the sizes of the
|
||||
(equivalent) block codes; Q is the alphabet size for the
|
||||
information-carrying channel symbols; Sync Energy is the fraction of
|
||||
transmitted energy devoted to synchronizing symbols; and S/N Threshold
|
||||
is the signal-to-noise ratio (in a 2500 Hz reference bandwidth) above
|
||||
which the probability of decoding is 50% or higher.
|
||||
|
||||
[[SLOW_TAB]]
|
||||
.Parameters of Slow Modes
|
||||
[width="90%",cols="3h,^3,^2,^1,^2,^2,^2,^2,^2,^2",frame=topbot,options="header"]
|
||||
|===============================================================================
|
||||
|Mode |FEC Type |(n,k) | Q|Modulation type|Keying rate (Baud)|Bandwidth (Hz)
|
||||
|Sync Energy|Tx Duration (s)|S/N Threshold (dB)
|
||||
|FT8 |LDPC, r=1/2|(174,87)| 8| 8-FSK| 6.25 | 50.0 | 0.27| 12.6 | -21
|
||||
|JT4A |K=32, r=1/2|(206,72)| 2| 4-FSK| 4.375| 17.5 | 0.50| 47.1 | -23
|
||||
|JT9A |K=32, r=1/2|(206,72)| 8| 9-FSK| 1.736| 15.6 | 0.19| 49.0 | -27
|
||||
|JT65A |Reed Solomon|(63,12) |64|65-FSK| 2.692| 177.6 | 0.50| 46.8 | -25
|
||||
|QRA64A|Q-ary Repeat Accumulate|(63,12) |64|64-FSK|1.736|111.1|0.25|48.4| -26
|
||||
| WSPR |K=32, r=1/2|(162,50)| 2| 4-FSK| 1.465| 5.9 | 0.50|110.6 | -31
|
||||
|===============================================================================
|
||||
|
||||
Submodes of JT4, JT9, JT65, and QRA64 offer wider tone spacings for
|
||||
circumstances that may require them, such significant Doppler spread.
|
||||
Table 3 summarizes the tone spacings, bandwidths, and approximate
|
||||
threshold sensitivities of the various submodes when spreading is
|
||||
comparable to tone spacing.
|
||||
|
||||
[[SLOW_SUBMODES]]
|
||||
.Parameters of Slow Submodes
|
||||
[width="50%",cols="h,3*^",frame=topbot,options="header"]
|
||||
|=====================================
|
||||
|Mode |Tone Spacing |BW (Hz)|S/N (dB)
|
||||
|FT8 |6.25 | 50.0 |-21
|
||||
|JT4A |4.375| 17.5 |-23
|
||||
|JT4B |8.75 | 30.6 |-22
|
||||
|JT4C |17.5 | 56.9 |-21
|
||||
|JT4D |39.375| 122.5 |-20
|
||||
|JT4E |78.75| 240.6 |-19
|
||||
|JT4F |157.5| 476.9 |-18
|
||||
|JT4G |315.0| 949.4 |-17
|
||||
|JT9A |1.736| 15.6 |-27
|
||||
|JT9B |3.472| 29.5 |-26
|
||||
|JT9C |6.944| 57.3 |-25
|
||||
|JT9D |13.889| 112.8 |-24
|
||||
|JT9E |27.778| 224.0 |-23
|
||||
|JT9F |55.556| 446.2 |-22
|
||||
|JT9G |111.111|890.6 |-21
|
||||
|JT9H |222.222|1779.5|-20
|
||||
|JT65A |2.692| 177.6 |-25
|
||||
|JT65B |5.383| 352.6 |-25
|
||||
|JT65C |10.767| 702.5 |-25
|
||||
|QRA64A|1.736| 111.1 |-26
|
||||
|QRA64B|3.472| 220.5 |-25
|
||||
|QRA64C|6.944| 439.2 |-24
|
||||
|QRA64D|13.889| 876.7 |-23
|
||||
|QRA64E|27.778|1751.7 |-22
|
||||
|=====================================
|
||||
|
||||
[[FAST_MODES]]
|
||||
=== Fast Modes
|
||||
|
||||
==== ISCAT
|
||||
|
||||
ISCAT messages are free-form, up to 28 characters in length.
|
||||
Modulation is 42-tone frequency-shift keying at 11025 / 512 = 21.533
|
||||
baud (ISCAT-A), or 11025 / 256 = 43.066 baud (ISCAT-B). Tone
|
||||
frequencies are spaced by an amount in Hz equal to the baud rate. The
|
||||
available character set is:
|
||||
|
||||
----
|
||||
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ /.?@-
|
||||
----
|
||||
|
||||
Transmissions consist of sequences of 24 symbols: a synchronizing
|
||||
pattern of four symbols at tone numbers 0, 1, 3, and 2, followed by
|
||||
two symbols with tone number corresponding to (message length) and
|
||||
(message length + 5), and finally 18 symbols conveying the user's
|
||||
message, sent repeatedly character by character. The message always
|
||||
starts with `@`, the beginning-of-message symbol, which is not
|
||||
displayed to the user. The sync pattern and message-length indicator
|
||||
have a fixed repetition period, recurring every 24 symbols. Message
|
||||
information occurs periodically within the 18 symbol positions set
|
||||
aside for its use, repeating at its own natural length.
|
||||
|
||||
For example, consider the user message `CQ WA9XYZ`. Including the
|
||||
beginning-of-message symbol `@`, the message is 10 characters long.
|
||||
Using the character sequence displayed above to indicate tone numbers,
|
||||
the transmitted message will therefore start out as shown in the first
|
||||
line below:
|
||||
|
||||
----
|
||||
0132AF@CQ WA9XYZ@CQ WA9X0132AFYZ@CQ WA9XYZ@CQ W0132AFA9X ...
|
||||
sync## sync## sync##
|
||||
----
|
||||
|
||||
Note that the first six symbols (four for sync, two for message
|
||||
length) repeat every 24 symbols. Within the 18 information-carrying
|
||||
symbols in each 24, the user message `@CQ WA9XYZ` repeats at its own
|
||||
natural length, 10 characters. The resulting sequence is extended as
|
||||
many times as will fit into a Tx sequence.
|
||||
|
||||
==== JT9
|
||||
|
||||
The JT9 slow modes all use keying rate 12000/6912 = 1.736 baud. By contrast, with
|
||||
the *Fast* setting submodes JT9E-H adjust the keying rate to match the
|
||||
increased tone spacings. Message durations are therefore much
|
||||
shorter, and they are sent repeatedly throughout each Tx sequence.
|
||||
For details see Table 4, below.
|
||||
|
||||
==== MSK144
|
||||
|
||||
Standard MSK144 messages are structured in the same way as those in
|
||||
the slow modes, with 72 bits of user information. Forward error
|
||||
correction is implemented by first augmenting the 72 message bits with
|
||||
an 8-bit cyclic redundancy check (CRC) calculated from the message
|
||||
bits. The CRC is used to detect and eliminate most false decodes at
|
||||
the receiver. The resulting 80-bit augmented message is mapped to a
|
||||
128-bit codeword using a (128,80) binary low-density-parity-check
|
||||
(LDPC) code designed by K9AN specifically for this purpose. Two 8-bit
|
||||
synchronizing sequences are added to make a message frame 144 bits
|
||||
long. Modulation is Offset Quadrature Phase-Shift Keying (OQPSK) at
|
||||
2000 baud. Even-numbered bits are conveyed over the in-phase channel,
|
||||
odd-numbered bits on the quadrature channel. Individual symbols are
|
||||
shaped with half-sine profiles, thereby ensuring a generated waveform
|
||||
with constant envelope, equivalent to a Minimum Shift Keying (MSK)
|
||||
waveform. Frame duration is 72 ms, so the effective character
|
||||
transmission rate for standard messages is up to 250 cps.
|
||||
|
||||
MSK144 also supports short-form messages that can be used after QSO
|
||||
partners have exchanged both callsigns. Short messages consist of 4
|
||||
bits encoding R+report, RRR, or 73, together with a 12-bit hash code
|
||||
based on the ordered pair of "`to`" and "`from`" callsigns. Another
|
||||
specially designed LDPC (32,16) code provides error correction, and an
|
||||
8-bit synchronizing vector is appended to make up a 40-bit frame.
|
||||
Short-message duration is thus 20 ms, and short messages can be
|
||||
decoded from very short meteor pings.
|
||||
|
||||
The 72 ms or 20 ms frames of MSK144 messages are repeated without gaps
|
||||
for the full duration of a transmission cycle. For most purposes, a
|
||||
cycle duration of 15 s is suitable and recommended for MSK144.
|
||||
|
||||
The modulated MSK144 signal occupies the full bandwidth of a SSB
|
||||
transmitter, so transmissions are always centered at audio frequency
|
||||
1500 Hz. For best results, transmitter and receiver filters should be
|
||||
adjusted to provide the flattest possible response over the range
|
||||
300Hz to 2700Hz. The maximum permissible frequency offset between you
|
||||
and your QSO partner ± 200 Hz.
|
||||
|
||||
==== Summary
|
||||
|
||||
.Parameters of Fast Modes
|
||||
[width="90%",cols="3h,^3,^2,^1,^2,^2,^2,^2,^2",frame="topbot",options="header"]
|
||||
|=====================================================================
|
||||
|Mode |FEC Type |(n,k) | Q|Modulation Type|Keying rate (Baud)
|
||||
|Bandwidth (Hz)|Sync Energy|Tx Duration (s)
|
||||
|ISCAT-A | - | - |42|42-FSK| 21.5 | 905 | 0.17| 1.176
|
||||
|ISCAT-B | - | - |42|42-FSK| 43.1 | 1809 | 0.17| 0.588
|
||||
|JT9E |K=32, r=1/2|(206,72)| 8| 9-FSK| 25.0 | 225 | 0.19| 3.400
|
||||
|JT9F |K=32, r=1/2|(206,72)| 8| 9-FSK| 50.0 | 450 | 0.19| 1.700
|
||||
|JT9G |K=32, r=1/2|(206,72)| 8| 9-FSK|100.0 | 900 | 0.19| 0.850
|
||||
|JT9H |K=32, r=1/2|(206,72)| 8| 9-FSK|200.0 | 1800 | 0.19| 0.425
|
||||
|MSK144 |LDPC |(128,80)| 2| OQPSK| 2000 | 2400 | 0.11| 0.072
|
||||
|MSK144 Sh|LDPC |(32,16) | 2| OQPSK| 2000 | 2400 | 0.20| 0.020
|
||||
|=====================================================================
|
||||
@@ -1,51 +0,0 @@
|
||||
use, intrinsic :: iso_c_binding, only: c_int, c_short, c_float, c_char, c_bool
|
||||
|
||||
include 'constants.f90'
|
||||
|
||||
!
|
||||
! these structures must be kept in sync with ../commons.h
|
||||
!
|
||||
type, bind(C) :: params_block
|
||||
integer(c_int) :: nutc
|
||||
logical(c_bool) :: ndiskdat
|
||||
integer(c_int) :: ntr
|
||||
integer(c_int) :: nfqso
|
||||
logical(c_bool) :: newdat
|
||||
integer(c_int) :: npts8
|
||||
integer(c_int) :: nfa
|
||||
integer(c_int) :: nfsplit
|
||||
integer(c_int) :: nfb
|
||||
integer(c_int) :: ntol
|
||||
integer(c_int) :: kin
|
||||
integer(c_int) :: nzhsym
|
||||
integer(c_int) :: nsubmode
|
||||
logical(c_bool) :: nagain
|
||||
integer(c_int) :: ndepth
|
||||
integer(c_int) :: ntxmode
|
||||
integer(c_int) :: nmode
|
||||
integer(c_int) :: minw
|
||||
logical(c_bool) :: nclearave
|
||||
integer(c_int) :: minsync
|
||||
real(c_float) :: emedelay
|
||||
real(c_float) :: dttol
|
||||
integer(c_int) :: nlist
|
||||
integer(c_int) :: listutc(10)
|
||||
integer(c_int) :: n2pass
|
||||
integer(c_int) :: nranera
|
||||
integer(c_int) :: naggressive
|
||||
logical(c_bool) :: nrobust
|
||||
integer(c_int) :: nexp_decode
|
||||
character(kind=c_char, len=20) :: datetime
|
||||
character(kind=c_char, len=12) :: mycall
|
||||
character(kind=c_char, len=6) :: mygrid
|
||||
character(kind=c_char, len=12) :: hiscall
|
||||
character(kind=c_char, len=6) :: hisgrid
|
||||
end type params_block
|
||||
|
||||
type, bind(C) :: dec_data
|
||||
real(c_float) :: ss(184,NSMAX)
|
||||
real(c_float) :: savg(NSMAX)
|
||||
real(c_float) :: sred(5760)
|
||||
integer(c_short) :: id2(NMAX)
|
||||
type(params_block) :: params
|
||||
end type dec_data
|
||||
Reference in New Issue
Block a user