OSCILLOSCOPE: The device which convert any electrical signal to visual.(waveform) The graph, usually called the trace, is drawn by a beam of electrons striking the phosphor coating of the screen making it emit light, usually green or blue. This is similar to the way a television picture is produced. WHY DUAL TRACE? Unlike single trace oscilloscope,dual trace oscilloscope can display two traces on the screen, allowing you to easily compare the input and output. FOREXAMPLE: input and output of an amplifier.

Amplifier inputAmplifier output

Input and output comparison on DTO

Single trace oscilloscope Which this old box cant

Difference Between DTO and Dual Beam Oscilloscope  A dual-trace oscilloscope should not be confused with a dual- beam oscilloscope.  Dual-beam oscilloscopes produce two separate electron beams on a single scope, which can be individually or jointly controlled.  Dual-trace refers to a single beam in a CRT that is shared by two channels.

DTO WORKING MODES: VERT MODETRIGGER SIGNAL SOURCE CH 1 CH 2 ALTSwitches between CH1 and CH2 input signals after each sweep CHOPSwitches between Ch1 and CH2 input signal for each sweep ADDCombined signal of CH1 and CH2

Front panel

FRONT PANEL CAL TERMINAL INTENSITY CONTROL FOCUS POSITION CONTROL VOLTS/DIV INPUT JACK CH1 CH2 ALT CHOP ADD

Dual Trace Oscilloscope Works In Following Two Modes  alternate mode  chopped mode

Alternate mode In alternate mode an electronic switch alternates between signal A & B.

 In this the electronic switch alternates between channels A and B, letting each through for one cycle of the horizontal sweep.  The display is blanked during the flyback and hold-off periods, as in a conventional oscilloscope.  The screen will show a stable display of both the waveform at channels A and B.  The alternate mode cannot be used for displaying very low frequency signals.

Chopped mode In the chopped mode the switch free runs at very high frequency.

 In this mode the electronic switch free runs at a high frequency of the order of 100 kHz to 500 kHz.  The result is that small segments from channels A and B are connected alternately to the vertical amplifier, and displayed on the screen.  If the chopping rate is much faster than the horizontal sweep rate, the display will show a continuous line for each channel.  If the sweep rate approaches the chopping rate then the individual segments will be visible, and the alternate mode should now be used.

Typical Applications  Troubleshoot electro­optical and electrical systems.  Observe a triggered event separately or relative to the trigger itself.  Use with analog light meter output to visualize intensity of a source.  Check response of a silicon, InGaAs, or avalanche photod iode.  Analyze signals produced by function generators.  Evaluate system performance.

THANK u