FSK-2 modulation with 620 Hz shift and 100 Baud speed, in use by Polish Intel service.
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pic. 1 - baudrate and shift |
The signal exhibits clean ACF spikes at 96 bits (~960ms lenght). Looking morecloselyone can distinguish six periods of16bits, most likelythey represent a five digits code and a separator between the groups as also shown in the bitstream (pic. 3).
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pic. 2 - 96 bits ACF (6 x 16 bits digits) |
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pic. 3 |
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pic. 4 |