dso is use for measurement ac as well as dc voltage and current. and also use for faulty components in various circuit .it stored wave form in digital memory.it easy to operate. cursor measurement is possible.

1. Gujarat power engineeringGujarat power engineering
and research instituteand research institute
Sub-electrical measurement and measuring
instrument
Topic-digital storage oscilloscope
Guided by
Prof.sanjay patel
Created by
Kajal patel (161040109018)
Him patel (161040109016)

2. Why DSO is require?Why DSO is require?
►The storage tube can preserve a stored aThe storage tube can preserve a stored a
waveform for a finite amount of timewaveform for a finite amount of time
eventually , waveform is lost . the power toeventually , waveform is lost . the power to
storage a tube must be present as long asstorage a tube must be present as long as
image is so to be stored .image is so to be stored .
►Storage cathode ray tube is concededlyStorage cathode ray tube is concededly
more expensive then conventional tube andmore expensive then conventional tube and
require additional power.require additional power.

3. What is DSO?What is DSO?
►The digital storage oscilloscope is a methodThe digital storage oscilloscope is a method
of trace storage. in this technique theof trace storage. in this technique the
waveform to be stored is digitized, stored inwaveform to be stored is digitized, stored in
digital memory ,and retrived for display ondigital memory ,and retrived for display on
the storage ocilloscope.the stored displaythe storage ocilloscope.the stored display
display can be displayed can be displayeddisplay can be displayed can be displayed
indefinitely as long as power os applied toindefinitely as long as power os applied to
memory,which can be supplied with smallmemory,which can be supplied with small
battery.battery.

4. Block diagramBlock diagram

5. Block diagram of DSOBlock diagram of DSO
►The input is amplified and attenuated withThe input is amplified and attenuated with
input amplifier.input amplifier.
►The dso uses the same type of inputThe dso uses the same type of input
circuitry and oscilloscope probes as acircuitry and oscilloscope probes as a
conventional mode, bypassing the digitizingconventional mode, bypassing the digitizing
and storing feature.and storing feature.
►The output of input signal amplifiers feedThe output of input signal amplifiers feed
Ad converter. the main requirement of AdAd converter. the main requirement of Ad
converter is its speed, while accuracy andconverter is its speed, while accuracy and
resolution are of secondary impedance.resolution are of secondary impedance.

6. ►The digitized output in binary form BCDThe digitized output in binary form BCD
form. generally successive approximationform. generally successive approximation
type of ADC is used in digital storagetype of ADC is used in digital storage
oscilloscope .if a 12 bit converter is usedoscilloscope .if a 12 bit converter is used
then accuracy of about 0.1% and resolutionthen accuracy of about 0.1% and resolution
of about 0.025%is obtained, while if a 10 bitof about 0.025%is obtained, while if a 10 bit
ADC is used then resolution of about 0.1%ADC is used then resolution of about 0.1%
is obtained.is obtained.
►Digitizing the analogy signal means to takeDigitizing the analogy signal means to take
sample of the input signal at periodicsample of the input signal at periodic

7. ►Digitizing the antilog signal means to takeDigitizing the antilog signal means to take
sample of the input signal at periodicsample of the input signal at periodic
intervals of times sampling rate should beintervals of times sampling rate should be
greater than twice the highest frequency ofgreater than twice the highest frequency of
information present in the input signal, soinformation present in the input signal, so
that the sampling theory is satisfied. Thisthat the sampling theory is satisfied. This
ensures that aliasing effect will occur andensures that aliasing effect will occur and
there is no loss. The sampling rate may bethere is no loss. The sampling rate may be
as high as 100,000 samples per second.as high as 100,000 samples per second.
For such high sampling rates, a fastFor such high sampling rates, a fast
conversion A/D converter is required. Flashconversion A/D converter is required. Flash
A/D converter are used at the cost ofA/D converter are used at the cost of
decrease the resolution with increasing indecrease the resolution with increasing in
sampling rate.sampling rate.

8. ►The size of memory reacted to amount ofThe size of memory reacted to amount of
horizontally segment of the trace that behorizontally segment of the trace that be
divided into one sweep of the time base.egdivided into one sweep of the time base.eg
if the memory site is 1Kthen the trace willif the memory site is 1Kthen the trace will
divided into 1000 horizontal segments. If 10divided into 1000 horizontal segments. If 10
ADC is use then frequcy response of 25ADC is use then frequcy response of 25
KHz is obtained; the total memory storageKHz is obtained; the total memory storage
capacity is 4096 for a single channel ,2048capacity is 4096 for a single channel ,2048
for a two channel 1024 for a 4 channelsfor a two channel 1024 for a 4 channels
each.each.

9. ►The selection of the sampling rate andThe selection of the sampling rate and
memory size is depend on the type ofmemory size is depend on the type of
waveform being record's an along signal iswaveform being record's an along signal is
sampled at suitable rates, the data point aresampled at suitable rates, the data point are
read able on to the memory once the singleread able on to the memory once the single
is stroge, the required manipulations can beis stroge, the required manipulations can be
done.done.
► A continues storage oscilloscope consistsA continues storage oscilloscope consists
of the feature called pre-retrigger view. Thisof the feature called pre-retrigger view. This
indicated that events that occurred beforeindicated that events that occurred before

10. ►the trigger input single was applied arethe trigger input single was applied are
displayed the selection is percentagedisplayed the selection is percentage
selection .selection .
►This mode is useful when failure occurs.This mode is useful when failure occurs.
►Single shot events are some time transientSingle shot events are some time transient
in a nature and hence they quickly lostin a nature and hence they quickly lost
unless the waveform is storage theunless the waveform is storage the
observer cannot see such event such eventobserver cannot see such event such event
are stroge in the memory of the dso andare stroge in the memory of the dso and
memory can be rapidly read and on thememory can be rapidly read and on the

11. ►Screen continues wave form can beScreen continues wave form can be
displayed.displayed.
►The DSO following mode of operationsThe DSO following mode of operations
1.1. Roll mode : this is used observe the fastRoll mode : this is used observe the fast
varying singlevarying single
2.2. Store mode : it is called as “Refresh” modeStore mode : it is called as “Refresh” mode
and is most commonly used.and is most commonly used.
3.3. Hold and save mode: this mode is used toHold and save mode: this mode is used to
lock to previously saved single.lock to previously saved single.

12. AdvantagesAdvantages
►Infinite storage time.Infinite storage time.
►Easy to operateEasy to operate
►Single processing is possibleSingle processing is possible
►Cursor measurement is possibleCursor measurement is possible
►It is a capable of displaying X-Y plots and P-It is a capable of displaying X-Y plots and P-
V diagram and B-H curveV diagram and B-H curve
► Pretriggering feature allows display ofPretriggering feature allows display of
waveform, before the trigger pulse.waveform, before the trigger pulse.

13. ApplicationsApplications
► It can be used to measurementIt can be used to measurement
► A.C as will as D.C voltages and currents.A.C as will as D.C voltages and currents.
► Frequency time period time intervalFrequency time period time interval
between two signals etc.between two signals etc.
► inductance and capacitanceinductance and capacitance
► Used to check faulty components inUsed to check faulty components in
various circuitsvarious circuits
► Used to determine the various modulationUsed to determine the various modulation