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 Bd. 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).
|
Parameter |
Value |
|
Frequency range |
HF |
|
Operation modes |
Half-duplex ARQ |
|
Modulation |
PSK2A, PSK4A, PSK8A,
PSK16A, ASK2PSK8, ASK4PSK16, 2DPSK2A |
|
Symbol rate |
8 x 62.5 Bd |
|
AFC |
±400 Hz, with max. single step ±15 Hz |
|
Receiver settings |
DATA, CW, LSB or USB |
|
Input format(s) |
AF, IF |
|
Additional Info |
ITA-5, Optional Mode |
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 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:
Ø ROBUST: 60%
Ø NORMAL: 75%
Ø FAST: 90%
Ø OFF: 100% (i.e., no error correction)
The level of RS Efficiency is automatically detected by the demodulator.
After successful synchronization, it may take up to a minute before any text is output in the GUI.
Using Options | CRC Table a certain CRC mask can be defined, see CRC Table.
The Options | Display Mode provides the options to display All Frames or Error free Frames, which means frames with the correct CRC check.