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# ADC
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The ADC is used as an on-board oscilloscope.
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During normal WorldFIP operation the ADC will be deactivated with the
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related power supplies turned off.
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In case of a failing segment, the macrocycle would change to a simple
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predefined one (ex. a presence variable request to nodes 1..255) and the
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ADC would be turned on and connected to the secondary side of the
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transformer. The ADC could also connect to the primary/bus side of the
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transformer; that could be risky though.
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To simplify the design of the board, the same ADC used in the FMC-ADC
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has been selected.
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Figure 1 shows a WorldFIP frame as it appears on the primary side of the
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transformer. Each signal of the differential pair is **0 +-2.3V**.
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The calculated rising time is 70 ns; through a simple rule of thumb this
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translates to a bandwidth of **5
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MHz**.
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![](/uploads/9b5ea348f440b68e48441338ee76aa62/diff_signal_primary.png)
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\> Figure 1: probing on the FieldTR primary side
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Figure 2 shows the frame on the secondary side of the transformer. Each
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signal of the differential pair is at **2.3
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+-1.5V**.
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![](/uploads/59c7fc09ec601245f1086cfbe3125189/diff_signal_secondary.png)
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\> Figure 2: probing on the FieldTR secondary side
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