the screen as a result…the software forces the sweep data into one or
other of the bins even though the data may have been at one end of
the “bin” or the other.
RIS mode is not well suited to very slow input signals or signals that
have jitter. This will lead to an uncertainty in the trigger instant and
hence the sweep data will appear in the wrong “bins” and so the
displayed waveform will not “lock” on the screen over time.
Please note that in RIS mode it is not possible to observe the
probe compensation output
. This is because it is precisely phase-
locked to the ADC’s clock hence there is no way to take random
sweeps to build up the picture...every sweep comes out in the same
bin due to the phase lock. This is normal.
2.7 Trigger Modes
The USBscope50 can use two main types of triggering. These
modes are used when the “Run” button or the “Trigger Single”
button has been pressed causing the scope to enter the run state.
i.e. a spike. This is normal.
Elan Digital Systems Ltd.
22
USBscope50 USER’S GUIDE Iss8
