As we already discussed dual trace oscilloscope which is different from double beam oscilloscope.I was asked what is dual or double beam oscilloscope many times from visitors.So now here we will discuss the working of double beam oscilloscope.
Dual or Double Beam Oscilloscope Working Principle:
The double or dual trace oscilloscope cannot capture two fast transient events, as it cannot switch quickly enough between traces.The dual or double beam oscilloscope has two separate electron beams, and therefore two completely separate vertical channels, as in the figure waveforms of dual or double trace oscilloscope operating in alternate mode.
The two channels may have a common time base system, as in the figure double or dual trace oscilloscope, or they may have independent time base circuits, as shown in the below figure. An independent time base allows different sweep rates for the two but increases the size and weight of the oscilloscope.
Two methods are used for generating the two electron beams within the CRO. The first method uses a double gun tube.This allows the brightness and focus of each beam to be controlled separately but it is bulkier than a split beam tube.
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Must Read:
- Working Principle of Dual Trace Oscilloscope and Block Diagram
- Digital Storage Oscilloscope(DSO) Working Principle and its Operation
- Lissajous Patterns of CRO or Cathode ray oscilloscope
Dual or Double Beam Oscilloscope Block Diagram:
In the second method, known as a split beam, a single electron gun is used.A horizontal splitter plate is placed between the last anode and the Y deflection plates in the cro.This plate is held at the same potential as the anode and it goes along the length of the tube, between the two vertical deflection plates, It, therefore, isolates the two channels.
The split beam arrangement has half the brightness of a single beam, Which has disadvantages at high frequency operation.An alternative method of splitting the beam, which improves its brightness, is to have two apertures in the last anode, instead of one, so that two beams emerge from it.So it is named as dual or double beam oscilloscope.
The disadvantage of the split beam construction in dual or double Beam Oscilloscope is that the two display may have noticeably different brightness if operated at widely spaced sweep speeds.The brightness and focus control also affect the two traces at the same time.
Conclusion:
Now here we have discussed working principle and block diagram of double beam oscilloscope.You can download this article as pdf, ppt.In the previous article, I explained the theory on dual trace oscilloscope.
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