Chapter 3: Testing Performance
DC Measurement Accuracy (Single Cursor) Test
3–11
DC Measurement Accuracy (Single Cursor) Test
Specifications
Example: Single cursor measurement 70 mV input @ 20 mV/div, 0 V channel offset with no averaging:
expected measurement error < ±[(1%(160 mV)) + (1%(160 mV) + (0.4%(160 mV)/2)] = ±3.52 mV.
Equipment Required
Connections
DC Gain Accuracy ±1% of full scale at full resolution channel scale
Offset Accuracy ±(2% of channel offset + 1% of full scale)
Vertical Resolution 8 bits, ≥12 bits with averaging
DC Voltage Measurement Accuracy
Single Cursor ±[(DC gain accuracy) + (offset accuracy) + (resolution/2)]
Dual Cursor ±[(DC gain accuracy) + (resolution)]
Full scale is defined as 8 vertical divisions. Vertical divisions are defined by the major scale settings above non-major scale
settings. The major scale settings are 10 mV, 20 mV, 50 mV, 100 mV, 200 mV, 500 mV and 1 V.
Vertical resolution for 8 bits = 0.4% of full scale, for 12 bits = 0.024% of full scale
Description Critical Specifications Recommended Model/
Part Numbers
Digital Multimeter DC voltage measurement accuracy better than ±0.1% of reading Agilent 34401A or
Agilent 3458A
Cable Assembly
(2 required)
50Ω characteristic impedance, BNC (m) connectors Agilent 8120-1840
Adapter BNC Tee (m)(f)(f) Agilent 1250-0781
Adapter BNC (f) to dual banana Agilent 1251-2277
5485x Scope Under Test
Aux Out
Chan 1 IN
Chan 2 IN
Chan 3 IN
Chan 4 IN
Digital Multimeter
BNC Tee
connected directly to
scope channel input
Input