Digital storage ocilloscope

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 engineering Gujarat 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 a The storage tube can preserve a stored a
waveform for a finite amount of time waveform for a finite amount of time
eventually , waveform is lost . the power to eventually , waveform is lost . the power to
storage a tube must be present as long as storage 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 concededly Storage cathode ray tube is concededly
more expensive then conventional tube and more expensive then conventional tube and
require additional power.require additional power.

3. What is DSO?What is DSO?
►The digital storage oscilloscope is a method The digital storage oscilloscope is a method
of trace storage. in this technique the of trace storage. in this technique the
waveform to be stored is digitized, stored in waveform to be stored is digitized, stored in
digital memory ,and retrived for display on digital memory ,and retrived for display on
the storage ocilloscope.the stored display the storage ocilloscope.the stored display
display can be displayed can be displayed display can be displayed can be displayed
indefinitely as long as power os applied to indefinitely as long as power os applied to
memory,which can be supplied with small memory,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 with The input is amplified and attenuated with
input amplifier.input amplifier.
►The dso uses the same type of input The dso uses the same type of input
circuitry and oscilloscope probes as a circuitry and oscilloscope probes as a
conventional mode, bypassing the digitizing conventional mode, bypassing the digitizing
and storing feature.and storing feature.
►The output of input signal amplifiers feed The output of input signal amplifiers feed
A\d converter. the main requirement of A\d A\d converter. the main requirement of A\d
converter is its speed, while accuracy and converter is its speed, while accuracy and
resolution are of secondary impedance.resolution are of secondary impedance.

6. ►The digitized output in binary form BCD The digitized output in binary form BCD
form. generally successive approximation form. generally successive approximation
type of ADC is used in digital storage type of ADC is used in digital storage
oscilloscope .if a 12 bit converter is used oscilloscope .if a 12 bit converter is used
then accuracy of about 0.1% and resolution then accuracy of about 0.1% and resolution
of about 0.025%is obtained, while if a 10 bit of 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 take Digitizing the analogy signal means to take
sample of the input signal at periodic sample of the input signal at periodic
intervals of times sampling rate should be intervals of times sampling rate should be
greater than twice the highest frequency of greater than twice the highest frequency of
information present in the input signal, so information present in the input signal, so
that the sampling theory is satisfied. This that the sampling theory is satisfied. This
ensures that aliasing effect will occur and ensures that aliasing effect will occur and
there is no loss. The sampling rate may be there 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 fast For such high sampling rates, a fast
conversion A/D converter is required. Flash conversion A/D converter is required. Flash
A/D converter A/D converter

7. ►Digitizing the antilog signal means to take Digitizing the antilog signal means to take
sample of the input signal at periodic sample of the input signal at periodic
intervals of times sampling rate should be intervals of times sampling rate should be
greater than twice the highest frequency of greater than twice the highest frequency of
information present in the input signal, so information present in the input signal, so
that the sampling theory is satisfied. This that the sampling theory is satisfied. This
ensures that aliasing effect will occur and ensures that aliasing effect will occur and
there is no loss. The sampling rate may be there 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 fast For such high sampling rates, a fast
conversion A/D converter is required. Flash conversion A/D converter is required. Flash
A/D converter are used at the cost of A/D converter are used at the cost of
decrease the resolution with increasing in decrease the resolution with increasing in
sampling rate.sampling rate.

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

9. ►The selection of the sampling rate and The selection of the sampling rate and
memory size is depend on the type of memory size is depend on the type of
waveform being record's an along signal is waveform being record's an along signal is
sampled at suitable rates, the data point are sampled at suitable rates, the data point are
read able on to the memory once the single read able on to the memory once the single
is stroge, the required manipulations can be is stroge, the required manipulations can be
done. done.
► A continues storage oscilloscope consists A continues storage oscilloscope consists
of the feature called pre-retrigger view. This of 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 are the trigger input single was applied are
displayed the selection is percentage displayed 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 transient Single shot events are some time transient
in a nature and hence they quickly lost in a nature and hence they quickly lost
unless the waveform is storage the unless the waveform is storage the
observer cannot see such event such event observer cannot see such event such event
are stroge in the memory of the dso and are stroge in the memory of the dso and
memory can be rapidly read and on the memory can be rapidly read and on the

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

12. Advantages Advantages
►Infinite storage time.Infinite storage time.
►Easy to operate Easy to operate
►Single processing is possible Single processing is possible
►Cursor measurement is possible Cursor 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 curve V diagram and B-H curve
► Pretriggering feature allows display of Pretriggering 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 interval Frequency time period time interval
between two signals etc.between two signals etc.
► inductance and capacitanceinductance and capacitance
►Used to check faulty components in Used to check faulty components in
various circuitsvarious circuits
►Used to determine the various modulationUsed to determine the various modulation