FAQs from Rohde & Schwarz

Very small pulses with slow time bases - how can I make them visible?


I want to measure pulses of a width of 10 us. But the repetition rate is very slow, about 1 s. To measure the time between the pulses I need a slow time base of 200 ms/div. But with that time base the pulses are not visible any more. With old scopes that was no problem. Is there a way to get them visible with new scopes?


With the following steps it is possible to see the pulses:

  • Press the key "Acquisition" and choose the highest possible record length. In addition choose "Peak Detect" as "Acquire Mode"
  • Now you will see the pulse already, but very dimm.
  • In the menue go to "Display" and enable "Inverse Brightness". Then the pulse becomes visible much better.
FAQ very small pulses with slow time bases
This screenshot shows a pulse (width = 10 us, repetition rate 1 s) at a time base of 200 ms/div
Open Lightbox

Another hint:

Please do not use the function "High Resolution". In reality it reduces the real sampling rate. A better wording could be "low noise". It calculates the average of severals samples which reduces noise but it reduces also the sampling rate. In that case the very small pulse is not detected any more.