Short Notes: Digital Storage Oscilloscope | Electrical and Electronic Measurements - Electrical Engineering (EE) PDF Download

 Page 1


 
 
Definition: The digital storage oscilloscope is defined as the 
oscilloscope which stores and analysis the signal digitally, i.e. in 
the form of 1 or 0 preferably storing them as analogue signals. The 
digital oscilloscope takes an input signal, store them and then display it 
on the screen. The digital oscilloscope has advanced features of 
storage, triggering and measurement. Also, it displays the 
signal visually as well as numerically. 
 
 
Working Principle of Digital Storage Oscilloscope 
The digital oscilloscope digitises and stores the input signal. This can 
be done by the use of CR y a R e d o h t a C ( T  ) e b u T and digital memory. 
The block diagram of the basic digital oscilloscope is shown in the 
figure below. The digitisation can be done by taking the sample input 
signals at periodic waveforms. 
 
The maximum frequency of the signal which is measured by the digital 
oscilloscope depends on the two factors. Theses factors are the 
1. Sampling rate 
2. Nature of converter. 
Page 2


 
 
Definition: The digital storage oscilloscope is defined as the 
oscilloscope which stores and analysis the signal digitally, i.e. in 
the form of 1 or 0 preferably storing them as analogue signals. The 
digital oscilloscope takes an input signal, store them and then display it 
on the screen. The digital oscilloscope has advanced features of 
storage, triggering and measurement. Also, it displays the 
signal visually as well as numerically. 
 
 
Working Principle of Digital Storage Oscilloscope 
The digital oscilloscope digitises and stores the input signal. This can 
be done by the use of CR y a R e d o h t a C ( T  ) e b u T and digital memory. 
The block diagram of the basic digital oscilloscope is shown in the 
figure below. The digitisation can be done by taking the sample input 
signals at periodic waveforms. 
 
The maximum frequency of the signal which is measured by the digital 
oscilloscope depends on the two factors. Theses factors are the 
1. Sampling rate 
2. Nature of converter. 
Sampling Rate – For safe analysis of input signal the sampling theory 
is used. The sampling theory states that the sampling rate of the signal 
must be twice as fast as the highest frequency of the input signal. The 
sampling rate means analogue to digital converter has a high fast 
conversion rate. 
Converter – The converter uses the expensive flash whose resolution 
decreases with the increases of a sampling rate. Because of the 
sampling rate, the bandwidth and resolution of the oscilloscope are 
limited. 
The need of the analogue to digital signal converters can also be 
overcome by using the shift register. The input signal is sampled and 
stored in the shift register. From the shift register, the signal is slowly 
read out and stored in the digital form. This method reduces the cost 
of the converter and operates up to 100 megasample per second. 
The only disadvantage of the digital oscilloscope is that it does not 
accept the data during digitisation, so it had a blind spot at that time. 
Waveform Reconstruction 
For visualising the final wave, the oscilloscopes use the technique of 
inter-polarization. The inter-polarization is the process of creating the 
new data points with the help of known variable data points. Linear 
interpolation and sinusoidal interpolation are the two processes of 
connecting the points together. 
Page 3


 
 
Definition: The digital storage oscilloscope is defined as the 
oscilloscope which stores and analysis the signal digitally, i.e. in 
the form of 1 or 0 preferably storing them as analogue signals. The 
digital oscilloscope takes an input signal, store them and then display it 
on the screen. The digital oscilloscope has advanced features of 
storage, triggering and measurement. Also, it displays the 
signal visually as well as numerically. 
 
 
Working Principle of Digital Storage Oscilloscope 
The digital oscilloscope digitises and stores the input signal. This can 
be done by the use of CR y a R e d o h t a C ( T  ) e b u T and digital memory. 
The block diagram of the basic digital oscilloscope is shown in the 
figure below. The digitisation can be done by taking the sample input 
signals at periodic waveforms. 
 
The maximum frequency of the signal which is measured by the digital 
oscilloscope depends on the two factors. Theses factors are the 
1. Sampling rate 
2. Nature of converter. 
Sampling Rate – For safe analysis of input signal the sampling theory 
is used. The sampling theory states that the sampling rate of the signal 
must be twice as fast as the highest frequency of the input signal. The 
sampling rate means analogue to digital converter has a high fast 
conversion rate. 
Converter – The converter uses the expensive flash whose resolution 
decreases with the increases of a sampling rate. Because of the 
sampling rate, the bandwidth and resolution of the oscilloscope are 
limited. 
The need of the analogue to digital signal converters can also be 
overcome by using the shift register. The input signal is sampled and 
stored in the shift register. From the shift register, the signal is slowly 
read out and stored in the digital form. This method reduces the cost 
of the converter and operates up to 100 megasample per second. 
The only disadvantage of the digital oscilloscope is that it does not 
accept the data during digitisation, so it had a blind spot at that time. 
Waveform Reconstruction 
For visualising the final wave, the oscilloscopes use the technique of 
inter-polarization. The inter-polarization is the process of creating the 
new data points with the help of known variable data points. Linear 
interpolation and sinusoidal interpolation are the two processes of 
connecting the points together. 
 
In interpolation, the lines are used for connecting the dot together. 
Linear interpolation is also used for creating the pulsed or square 
waveform. For sine waveform, the sinusoidal interpolation is utilised in 
the oscilloscope. 
 
Applications 
The applications of the DSO are 
• It checks faulty components in circuits 
• Used in the medical field 
• Used to measure capacitor, inductance, time interval between 
signals, frequency and time period 
• Used to observe transistors and diodes V-I characteristics 
• Used to analyze TV waveforms 
Page 4


 
 
Definition: The digital storage oscilloscope is defined as the 
oscilloscope which stores and analysis the signal digitally, i.e. in 
the form of 1 or 0 preferably storing them as analogue signals. The 
digital oscilloscope takes an input signal, store them and then display it 
on the screen. The digital oscilloscope has advanced features of 
storage, triggering and measurement. Also, it displays the 
signal visually as well as numerically. 
 
 
Working Principle of Digital Storage Oscilloscope 
The digital oscilloscope digitises and stores the input signal. This can 
be done by the use of CR y a R e d o h t a C ( T  ) e b u T and digital memory. 
The block diagram of the basic digital oscilloscope is shown in the 
figure below. The digitisation can be done by taking the sample input 
signals at periodic waveforms. 
 
The maximum frequency of the signal which is measured by the digital 
oscilloscope depends on the two factors. Theses factors are the 
1. Sampling rate 
2. Nature of converter. 
Sampling Rate – For safe analysis of input signal the sampling theory 
is used. The sampling theory states that the sampling rate of the signal 
must be twice as fast as the highest frequency of the input signal. The 
sampling rate means analogue to digital converter has a high fast 
conversion rate. 
Converter – The converter uses the expensive flash whose resolution 
decreases with the increases of a sampling rate. Because of the 
sampling rate, the bandwidth and resolution of the oscilloscope are 
limited. 
The need of the analogue to digital signal converters can also be 
overcome by using the shift register. The input signal is sampled and 
stored in the shift register. From the shift register, the signal is slowly 
read out and stored in the digital form. This method reduces the cost 
of the converter and operates up to 100 megasample per second. 
The only disadvantage of the digital oscilloscope is that it does not 
accept the data during digitisation, so it had a blind spot at that time. 
Waveform Reconstruction 
For visualising the final wave, the oscilloscopes use the technique of 
inter-polarization. The inter-polarization is the process of creating the 
new data points with the help of known variable data points. Linear 
interpolation and sinusoidal interpolation are the two processes of 
connecting the points together. 
 
In interpolation, the lines are used for connecting the dot together. 
Linear interpolation is also used for creating the pulsed or square 
waveform. For sine waveform, the sinusoidal interpolation is utilised in 
the oscilloscope. 
 
Applications 
The applications of the DSO are 
• It checks faulty components in circuits 
• Used in the medical field 
• Used to measure capacitor, inductance, time interval between 
signals, frequency and time period 
• Used to observe transistors and diodes V-I characteristics 
• Used to analyze TV waveforms 
• Used in video and audio recording equipment’s 
• Used in designing 
• Used in the research field 
• For comparison purpose, it displays 3D figure or multiple 
waveforms 
• It is widely used an oscilloscope 
 
Advantages 
The advantages of the DSO are 
• Portable 
• Have the highest bandwidth 
• The user interface is simple 
• Speed is high 
 
Disadvantages 
The disadvantages of the DSO are 
• Complex 
• High cost 
 
 
 
 
 
 
 
 
Page 5


 
 
Definition: The digital storage oscilloscope is defined as the 
oscilloscope which stores and analysis the signal digitally, i.e. in 
the form of 1 or 0 preferably storing them as analogue signals. The 
digital oscilloscope takes an input signal, store them and then display it 
on the screen. The digital oscilloscope has advanced features of 
storage, triggering and measurement. Also, it displays the 
signal visually as well as numerically. 
 
 
Working Principle of Digital Storage Oscilloscope 
The digital oscilloscope digitises and stores the input signal. This can 
be done by the use of CR y a R e d o h t a C ( T  ) e b u T and digital memory. 
The block diagram of the basic digital oscilloscope is shown in the 
figure below. The digitisation can be done by taking the sample input 
signals at periodic waveforms. 
 
The maximum frequency of the signal which is measured by the digital 
oscilloscope depends on the two factors. Theses factors are the 
1. Sampling rate 
2. Nature of converter. 
Sampling Rate – For safe analysis of input signal the sampling theory 
is used. The sampling theory states that the sampling rate of the signal 
must be twice as fast as the highest frequency of the input signal. The 
sampling rate means analogue to digital converter has a high fast 
conversion rate. 
Converter – The converter uses the expensive flash whose resolution 
decreases with the increases of a sampling rate. Because of the 
sampling rate, the bandwidth and resolution of the oscilloscope are 
limited. 
The need of the analogue to digital signal converters can also be 
overcome by using the shift register. The input signal is sampled and 
stored in the shift register. From the shift register, the signal is slowly 
read out and stored in the digital form. This method reduces the cost 
of the converter and operates up to 100 megasample per second. 
The only disadvantage of the digital oscilloscope is that it does not 
accept the data during digitisation, so it had a blind spot at that time. 
Waveform Reconstruction 
For visualising the final wave, the oscilloscopes use the technique of 
inter-polarization. The inter-polarization is the process of creating the 
new data points with the help of known variable data points. Linear 
interpolation and sinusoidal interpolation are the two processes of 
connecting the points together. 
 
In interpolation, the lines are used for connecting the dot together. 
Linear interpolation is also used for creating the pulsed or square 
waveform. For sine waveform, the sinusoidal interpolation is utilised in 
the oscilloscope. 
 
Applications 
The applications of the DSO are 
• It checks faulty components in circuits 
• Used in the medical field 
• Used to measure capacitor, inductance, time interval between 
signals, frequency and time period 
• Used to observe transistors and diodes V-I characteristics 
• Used to analyze TV waveforms 
• Used in video and audio recording equipment’s 
• Used in designing 
• Used in the research field 
• For comparison purpose, it displays 3D figure or multiple 
waveforms 
• It is widely used an oscilloscope 
 
Advantages 
The advantages of the DSO are 
• Portable 
• Have the highest bandwidth 
• The user interface is simple 
• Speed is high 
 
Disadvantages 
The disadvantages of the DSO are 
• Complex 
• High cost 
 
 
 
 
 
 
 
 
CRO Probes 
We can connect any test circuit to an oscilloscope through a probe. As 
CRO is a basic oscilloscope, the probe which is connected to it is also 
called CRO probe. 
We should select the probe in such a way that it should not create any 
loading issues with the test circuit. So that we can analyze the test circuit 
with the signals properly on CRO screen. 
CRO probes should have the following characteristics. 
• High impedance 
• High bandwidth 
The block diagram of CRO probe is shown in below figure. 
 
As shown in the figure, CRO probe mainly consists of three blocks. Those 
are probe head, co-axial cable and termination circuit. Co-axial cable 
simply connects the probe head and termination circuit. 
Types of CRO Probes 
CRO probes can be classified into the following two types. 
• Passive Probes 
• Active Probes 
Now, let us discuss about these two types of probes one by one. 
Passive Probes 
If the probe head consists of passive elements, then it is called passive 
probe. The circuit diagram of passive probe is shown in below figure.