User's Manual

Chapter 2 Hardware Overview

Oscilloscope Mode

The ADC converts at a constant rate of 100 MS/s, but you can choose to

store only a fraction of these samples into memory at a lower rate. This

allows you to store waveforms using fewer data points and decreases the

burden of storing, analyzing, and displaying the waveforms. If you need

faster sampling rates, you can use Random Interleaved Sampling (RIS) to

effectively increase the sampling rate to 1 GS/s for repetitive waveforms.

In oscilloscope mode, all signals up to 100 MHz are passed to the ADC.

You need to ensure that your signal is band-limited to prevent aliasing.

Aliasing and other sampling terms are described more thoroughly in

Appendix B, Digitizer Basics.

Sampling Methods—Real Time and RIS

There are two sampling methods available in oscilloscope mode, Real Time

and RIS. Using real time sampling, you can acquire data at a rate of

100 MS/n where n is a number from 1 to 4.3 million. RIS sampling can be

used on repetitive signals to effectively extend the sampling rate above

100 MS/s. In RIS mode, you can sample at rates of 100 MS/s * n, where n

is a number from 2 to 10. The available sampling rates, resolutions, and

bandwidth for flexible resolution mode are shown in Table 2-2.

Flexible Resolution Mode

Table 2-2 shows the relationship between the available sampling rates and

the corresponding bandwidth for flexible resolution mode.

Table 2-2. Available Sampling Rates and Corresponding Bandwidth

in Flexible Resolution Mode

Sampling Rate Resolution Bandwidth

12.5 MS/s 12 bits 4MHz

5MS/s 14 bits 2MHz

2.5 MS/s 16 bits 800 kHz

1MS/s 18 bits 400 kHz

500 kS/s 18 bits 200 kHz

200 kS/s 19 bits 80 kHz

100 kS/s 19 bits 40 kHz

50 kS/s 20 bits 20 kHz