Oscilloscope

Sweep generator

t TIME/DIV Sweep

Trigger Fault

Trigger Sawtooth Trigger generation

Trigger Sawtooth Positive trigger level

Trigger Sawtooth Negative trigger level

Trigger Sawtooth Part of the signal: less than one period Hold-on time

Trigger Sawtooth Part of the signal: more than one period

Dual Trace oscilloscope Use a single-beam (one electron gun). Time-multiplex the inputs. – Chop mode or Alternate mode. Chopped mode: during the same sweep period, alternate between the two input signals. (better for slow sweep, i.e. high period) Alternate mode: one sweep period for each signal. ( better for fast sweep, i.e. low period)

X-Y mode X Y V y =A sin( t) V x =A sin ( t+θ)