Chinese 30-tone OFDM modem
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|---|---|
| Frequencies | 4.557 MHz,8.25 MHz,8.31 MHz,8.563 MHz,9.144 MHz,14.433 MHz,16.5 MHz |
| Frequency Range | 4.557 MHz - 16.5 MHz |
| Mode | LSB |
| Modulation | QPSK,BPSK,OFDM |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 3 kHz |
| Location | China, Worldwide |
| Short Description | A 30-tone OFDM data mode, probably used by Chinese military or other agencies. |
| I/Q Raw Recording | — |
| Audio Sample | |
This is a 30-tone OFDMOrthogonal Frequency-Division Multiplexing data mode that is believed to be used by Chinese military or other agencies.
The signal is transmitted in bursts, apparently in LSBLower Side Band Modulation mode, and there is a pilot tone at approximately 445 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. Each burst starts with a preamble of 4 tones, spaced 600 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). apart, first at about 650 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz)., modulated in QPSKQuadrature Phase-Shift Keying (2 bits per symbol). Actual data transmission happens with 30 OFDMOrthogonal Frequency-Division Multiplexing tones, each BPSKBinary Phase-Shift Keying (1 bit per symbol) modulated. Bandwidth of the signal is approximately 3 kHzKiloHertz (kHz) 10^3 Hz.
Samples[edit]
| Short bursts | Short bursts, possibly idling |
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Frequencies[edit]
Frequency range is not well known but the following frequencies have been used:
4557 kHzKiloHertz (kHz) 10^3 Hz
8250 kHzKiloHertz (kHz) 10^3 Hz
8310 kHzKiloHertz (kHz) 10^3 Hz
8563 kHzKiloHertz (kHz) 10^3 Hz
9144 kHzKiloHertz (kHz) 10^3 Hz
14429.5 kHzKiloHertz (kHz) 10^3 Hz (14433 kHzKiloHertz (kHz) 10^3 Hz?)
Video Examples[edit]
Additional Links[edit]
Additional Images[edit]
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