Technical data

38 4000 X-Series Oscilloscopes Service Guide
2 Testing Performance
Use a Blocking Capacitor to Reduce Noise
On the more sensitive ranges, such as 1 mV/div, 2 mV/div,
and 5 mV/div, noise may be a factor. To eliminate the noise,
add a BNC Tee, blocking capacitor, and shorting cap at the
oscilloscope channel input to shunt the noise to ground. See
Figure 4. If a BNC capacitor is not available, use an SMA
blocking capacitor, adapter, and cap. See “Blocking capacitor
and shorting cap” in the equipment list on page 24 for
details.
Figure 4 Using a Blocking Capacitor to Reduce Noise
To oscilloscope input
BNC shorting
cap
Blocking
Capacitor