Digital Storage Oscilloscope Block Diagram And Dual Trace Oscilloscope Block Diagram

Digital Storage Oscilloscope 

The dig­i­tal stor­age oscil­lo­scope input wave­form is dig­i­tal­ized and stored in mem­o­ry. Then. When need­ed, it is con­vert­ed back into an ana­log sig­nal and dis­played on an oscilloscope 

The input cir­cuit and CRO probe are used in the same way as in the con­ven­tion­al oscil­lo­scope. First the input sig­nal trav­els through the atten­u­a­tor and ampli­fi­er to the ana­log to dit­i­gal converter 

Its worm is the most impor­tant fac­tor for ADC. There­fore, flash type or suc­cess­ful approx­i­ma­tion type ADC is com­mon­ly used. 

Next, we will see how the ana­log input sig­nal is dig­i­tized. Sam­pling is the divi­sion of a wave­form into small­er parts (also called pulse) 

Hold­ing means delay­ing, which means that the sam­pling singla will not be out­put imme­di­ate­ly but will be out­put short­ly. Let’s see what hold­ing is done for. ADC may take some time to con­vert the ana­log sig­nal to digital 

If the next sam­pling pulse is giv­en to the ADC while the con­ver­sion is in progress it will not take. This can lead to infor­ma­tion loss In return we will not be able to recon­struct the orig­i­nal sig­nal. The sig­nal thus con­vert­ed to dig­i­tal is stored in memory 

ADC con­verts data in mem­o­ry into ana­log sig­nal before dis­play­ing sig­nal on CRT The ana­log sig­nal from the ADC is ampli­fied before being fed to the ver­ti­cal deflec­tion plate

The con­trol log­ic cir­cuit trans­mits the sweep sig­nal to the hor­i­zon­tal deflec­tion plate. It also con­trols and inte­grates the func­tions of all the cir­cuits in the oscilloscope 

Digital Storage Oscilloscope Advantages 

1. Dig­i­tal Stor­age Oscil­lo­scope is eas­i­er to oper­ate and has more capability 
2. Stor­age time is infinite 
3. The dis­play flex­i­bil­i­ty is avail­able. The num­ber of traces that can be stored and recalled depends on the size of the memory 
4. The cur­sor mea­sure­ment is possible 
5. The char­ac­ters can be dis­played on screen along with the wave­form infor­ma­tion such as min­i­mum and max­i­mum fre­quen­cy amplitude 
6. The X‑Y plots, B‑H curve, P‑V dia­grams can be displayed 
7. The pre trig­ger view­ing fea­tures allows to dis­play the wave­form before trig­ger pulse 
8. Keep­ing the records is pos­si­ble which includes trans­lat­ing the raw data into fin­ished infor­ma­tion exam­ple: com­put­ing para­me­ters of a cap­tured sig­nal like RMS val­ue, ener­gy stored etc. 

Applications of Digital Storage Oscilloscope 

1. It is used to give the visu­al rep­re­sen­ta­tion for a tar­get of radar such as aero­plane, ship etc. 
2. It is used to check the faulty com­po­nents in var­i­ous circuits 
3. It can be used in med­ical field 
4. It can be used to mea­sure AC as well as DC volt­ages and currents 
5. It is used to observe the radi­a­tion pat­tern gen­er­at­ed by the trans­mit­ting anten­na oscilloscope 
6. It can be used to mea­sure induc­tance and capacitance 
7. It can be used to mea­sure fre­quen­cy time period,time inter­val between signals 
8. It can be used to observe the VI char­ac­ter­is­tics of diodes and transistors 
9. Audio and video record­ing equipments 
10. Test­ing of sig­nals volt­age in radio broad­cast­ing equipment 
11. Used for test­ing sig­nal volt­ages in cir­cuit debugging 

Dual Trace CRO 

Dual beam CRO and dual trace CRO are used to com­pare one sig­nal with anoth­er Two elec­tron guns are used in the dual beam CRO. There is only one elec­tron gun in the Dual Trace CRO. But the two ver­ti­cal deflec­tion plates alter­nate­ly dis­play faster

Thus, they are con­tin­u­ous to the eyes and both sig­nals appear simul­ta­ne­ous­ly The block dia­gram of the dual trace CRO is shown in the fig­ure. It has two chan­nels A and B. Each chan­nel has its own atten­u­a­tor and pre-ampli­fi­er stage. 

So we can con­trol the ampli­tude of the two inputs sep­a­rate­ly The pre-ampli­fi­er out­put of the two chan­nels meets at the elec­tron­ic switch. 

The elec­tron­ic switch trans­mits only one chan­nel at a time to the ver­ti­cal ampli­fi­er via the delay line. The dual trace oscil­lo­scope is oper­at­ed by an elec­tron­ic switch in two modes 

They are Alter­nate mode and Chopped mode 

Alternate Mode

In this mode the elec­tron­ic switch con­nects chan­nel A and B alter­nate­ly or alter­nate­ly to the ver­ti­cal ampli­fi­er First, the elec­tron­ic switch con­nects chan­nel A to the ver­ti­cal ampli­fi­er for one cycle of the hor­i­zon­tal sweep Dis­con­nect Chan­nel A for the next cycle and con­nect chan­nel B to the ver­ti­cal amplifier 

The dis­play is blank dur­ing fly back and hold off When dis­play­ing high fre­quen­cy sig­nals the speed of the sweep sig­nal is greater than the decay time of the CRT phos­pho­er so the input sig­nals of chan­nel A and B can be seen con­stant­ly on the screen alter­nate mode to dis­play the low fre­quen­cy sig­nals can not be used 

Chopper Mode

In this mode the elec­tron­ic switch oper­ates at a fre­quen­cy of 100 to 500 KHz. From chan­nel A and B are giv­en as small seg­ments to the ver­ti­cal amplifier.

First the elec­tron­ic switch con­nects a small seg­ment from chan­nel A to the ver­ti­cal ampli­fi­er. Then dis­con­nect chan­nel A and con­nect a small seg­ment from chan­nel B to the ver­ti­cal ampli­fi­er. Chopped mode is used to dis­play low fre­quen­cy signals 

Also Read: Dig­i­tal Ener­gy Meter Block Diagram