Version: 16-Jan-2007
Output Response of the Comparator Board
16-Jan-07
For these measurements the Instrumentation Amp output (Probe 1) was measured as a function of the number of NTCs (on one Comparator Board) over threshold. During these measurements the Noise Source was removed.
Noise Sensitivity of Comparator Board Output Transmission
08-Jan-07
Tests done using the pre-prototype (wire-wrapped) Comparator Board (12-Jan-07 schematic) connected to ~100 m of coiled up ethernet cable connected to an instrumentation amp with low-pass filtering. A noise source (Dremel Tool) was turned on inside the coil of cable, and only ~1m away from the instrumentation amp.
In the following figures the Upper Scope Trace corresponds to Probe 2 (on one wire of the twisted pair) while the Lower Scope Trace corresponds to Probe 2 (after the instrumentation amp). Note also the different vertical scales for the two traces.
| 10 ms/div |  |
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| 50 us/div |  |
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| 10 us/div |  |
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Noise is reduced by a factor of >100 to the 10 mV level after the instrumentation amp.