BNC 1105 Universal Counter - Manual (Page 99)

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A.1 RMS Resolution
Rms (Typical) 100Hz 1KHz 10KHz 100KHz
1105 (10ms) 0.000000842 0.000003438 0.000013896 0.000067275
1105 (100ms) 0.0000001 0.000000828 0.000005093 0.000011508
1105 (1s) 0.000000001 0.000000098 0.000001212 0.000004869
Rms (Typical) 1MHz 10MHz 100MHz 1GHz
1105 (10ms) 0.000677504 0.004830870 0.042107484 0.611551072
1105 (100ms) 0.000101040 0.002272900 0.006344503 0.055991810
1105 (1s) 0.000058166 0.000469601 0.001275299 0.002602258
The graph doesn’t include the effects of trigger error. To place an upper bound on the added effect
of this error term, it’s necessary to determine the frequency error from the proper graph and add a
trigger error term as the following equation:
External source and input amplifier noise might advance or postpone the trigger points that define
the start and end of a measurement. The resulting timing uncertainty is a function of the slew rate
of the signal and the amplitude of spurious noise spikes (relative to the input hysteresis band).
The (rms) trigger error relative to a single trigger point is: