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AS3935

Datasheet - Detailed Descri p ti on

Figure 21. Detection Efficiencies vs. Distance for Different Setting of SREJ, if WDTH=0001

At the end of the signal verification, the AS3935 automatically returns to listening mode.

8.9.2 Energy Calculation

If the received signal is classified as lightning, the energy is calculated. The result of the energy calculation is then stored in the registers

REG0x06[4:0], REG0x05[7:0] and REG0x04[7:0]. This value is just a pure number and has no physical meaning.

8.9.3 Statistical Distance Estimation

The AS3935 generates an assessment of the estimated distance to the head of an approaching storm. This assessment is done based on

statistical calculation. The energy of the single event (lightning) provided by the Energy Calculation block is stored in an internal memory,

together with timing information, in the AS3935. The events stored in the memory are then correlated with a look-up table by the statistical

distance estimation block, which provides a final estimation of the distance to the head of the storm. The algorithm automatically deletes events,

which are older than a certain time. R7=0x01 means that the storm is right overhead, while R7=0x3F is displayed when the storm is out of range.

This algorithm is hardwired and not accessible from outside.

The estimated distance is directly represented in km in the register REG0x07[5:0] (binary encoded). The distance estimation can change also if

no new event triggers the AS3935, as older events can be purged.

Table 17. Distance Estimation

REG0x07[5:0]

Distance [km]

111111

Out of range

101000

40

100101

37

100010

34

60%

40%

20%

0.0

0

10

20

30

40

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

Radius [km]

SREJ