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| PACTOR-III Option
Solo per Enti Governativi |
|
Parameter |
Value |
|
System |
Half-duplex synchronous ARQ |
|
Center frequency |
In the range (−2900, 2900) [Hz];
automatic frequency control (AFC): +/−50 Hz |
|
Speed |
100.0 Baud |
|
Modulation |
DBPSK, DQPSK; 2, 6, 14, 16, or 18 tones |
|
Additional Info |
ITA-5 with block coding, CRC is displayed
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PACTOR-III is an adaptive transmission mode that
provides higher throughput and improved robustness compared to
PACTOR-I and –II, both of designed for operation within a
bandwidth of 500 Hz. To achieve the improved features,
PACTOR-III uses up to a maximum of 18 tones spaced 120 Hz, thus
occupying a maximum bandwidth of 2160 Hz. Six so-called Speed
Levels (SL) are specified, which are predefined combinations of
modulation type (DBPSK or DQPSK), channel coding and number of
tones (2, 6, 14, 16, or 18) as well as positions of tones. For
all Speed Levels, the modulation rate of each tone is 100 Baud.
B = DBPSK, Q = DQPSK) for the 6 Speed Levels
(SL). |
As propagation conditions
change, PACTOR-III is able to select the most suitable speed
level.
Each frame consists of the user data, a status byte, and two CRC
bytes. This input bit stream is then bit-interleaved and
convolutionally encoded. After that, the symbol mapping for the
different channels is done, and the resulting signals are
applied to the DxPSK modulators.
To extract the data from a
PACTOR-III signal, the signal is demodulated with the
appropriate number of DxPSK-demodulators, according to the speed
level. |
The center frequency must be adjusted to the
center between the lowest and highest tone in use. AFC (automatic
frequency control) is always enabled. After demodulation and bit
synchronization, the symbols of the channels are combined to one
bit stream, which is de-interleaved and passed through a
Viterbi-decoder. The CRC is used to check whether transmission
errors occurred. After successful synchronization, it may take
several tens of seconds before any text is output in the GUI.
In PACTOR-III, the data may be transmitted as ASCII without
compression or can be compressed with HUFFMAN or PSEUDO-MARKOV
compression (PMC). In addition, run length encoding (RLE) is
included. |
|
TN |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
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B |
|
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|
B |
|
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SL=1 |
|
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|
B |
|
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|
B |
|
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|
SL=2 |
|
|
|
B |
|
B |
|
B |
|
|
B |
|
B |
|
B |
|
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|
|
SL=3 |
|
|
B |
B |
B |
B |
B |
B |
B |
B |
B |
B |
B |
B |
B |
B |
|
|
|
SL=4 |
|
|
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
|
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|
SL=5 |
|
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
|
|
SL=6 |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
Q |
|
TF |
480 |
600 |
720 |
840 |
960 |
1080 |
1200 |
1320 |
1440 |
1560 |
1680 |
1800 |
1920 |
2040 |
2160 |
2280 |
2400 |
2520 |
|
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|
|
CLOVER-2000 Option
Solo per Enti Governativi |
|
Parameter |
Value |
|
System |
Half-duplex ARQ |
|
Center frequency |
In the range (−3000, 3000) [Hz];
automatic frequency control (AFC): +/−50 Hz |
|
Speed |
62.5 Baud |
|
Modulation |
PSK2A, PSK4A, PSK8A, PSK16A, ASK2PSK8,
ASK4PSK16, 2DPSK2A; 8 tones |
|
Additional Info |
ITA-5 |
|
|
CLOVER-2000 is an adaptive modulation system with
ARQ that uses Reed-Solomon (RS) coding to achieve a remarkable
performance even under worst HF propagation conditions. Data are
modulated onto eight tones spaced 250 Hz. The modulation rate
of each tone is 62.5 Baud. The supported modulation techniques
include binary phase-shift keying (PSK2A), quaternary PSK
(PSK4A), 8-PSK (PSK8A), 16-PSK (PSK16A), binary amplitude-shift
keying combined with 8-PSK (ASK2PSK8), quaternary ASK combined
with 16-PSK (ASK4PSK16), and two-channel diversity binary PSK
(2DPSK2A). |
RS coding is utilized to correct transmission
errors. Four coding levels (called RS Efficiency) are specified,
which allow for more or less error correction within a block.
The level of RS Efficiency is automatically
detected by the demodulator.
After successful synchronization, it may take
several tens of seconds before any text is output in the GUI. |
The percentages in the following list of coding
levels, relate the number of information symbols (user data) to
the block length, a block comprises user data and parity check
symbols:
- ROBUST: 60%
- NORMAL: 75%
- FAST: 90%
- OFF: 100% (i.e., no error correction)
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|
CLOVER-2 Option
Solo per Enti Governativi |
|
Parameter |
Value |
|
System |
Half-duplex ARQ |
|
Center frequency |
In the range( −3750, 3750) [Hz];
automatic frequency control (AFC): +/−50 Hz |
|
Speed |
31.25 Baud |
|
Modulation |
PSK2A, PSK4A, PSK8A, PSK16A, ASK2PSK8,
ASK4PSK16, 2DPSK2A; 4 tones |
|
Additional Info |
ITA-5 |
|
|
CLOVER-2 is an adaptive modulation system with
ARQ that uses Reed-Solomon (RS) coding to achieve a remarkable
performance even under the worst HF propagation conditions. Data
modulated onto four tones spaced 125 Hz. The modulation rate of
each tone is 31.25 Baud. The supported modulation techniques
include binary phase-shift keying (PSK2A), quaternary PSK
(PSK4A), 8-PSK (PSK8A), 16-PSK (PSK16A), binary amplitude-shift
keying combined with 8-PSK (ASK2PSK8), quaternary ASK combined
with 16-PSK (ASK4PSK16), and two-channel diversity binary PSK
(2DPSK2A). |
RS coding is utilized to correct transmission
errors. Four coding levels (called RS Efficiency) are specified,
which allow for more or less error correction within a block.
The level of RS Efficiency is automatically
detected by the demodulator.
After successful synchronization, it may take
several tens of seconds before any text is output in the GUI. |
The percentages in the following list of coding
levels, relate the number of information symbols (user data) to
the block length, a block comprises user data and parity check
symbols:
- ROBUST: 60%
- NORMAL: 75%
- FAST: 90%
- OFF: 100% (i.e., no error correction)
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