it contain the working of CRO & DO
IT CONTAINs all the subtopics related to it. it has Block diagram, internal working and much more.
Subject; Measurement & Instrumentation
Teacher; ma'am Falak Naz Pathan
MEHRAN UET SZAB CAMPUS KHAIRPUR MIR'S
Cathode Ray Oscilloscope CRO & Digital Oscilloscope 'S WORKING
1. General Purpose CRO
Waqar Ali Bhatti (K-18ES35)
Ayaz Gul Hingorjo (k-18es21)
Abdul Qayoom Mangrio (k-18es31)
2. The Cathode-ray-Oscilloscope (CRO) is a common laboratory
instruments that provides;
1-Accurate time & amplitude
2-Measurements of voltage signals over a wide range of frequencies.
Its reliability, Stability, and ease of operation make it suitable as a
general purpose laboratory instrument. The heart of the CRO is a
cathode-ray tube shown in figure
5. The electron gun assembly of CRT consists of an indirectly heated
cathode, a control grid surrounding the cathode, a focusing anode and an
accelerating anode. The main function of the electron gun assembly
is to provide a focused electron beam which is accelerated
towards the phosphor screen.
6. Parts of Oscilloscope
A basic oscilloscope consists of three different systems
the vertical system, horizontal system, and trigger system.
Each system contributes to the oscilloscope's ability to accurately reconstruct a signal.
The front panel of an oscilloscope is divided into three sections labeled
i-Vertical ii- Horizontal iii-Trigger.
7.
8. Control of Oscilloscope
The control available on most oscilloscopes provides a wide range of operating condition and this make
the instrument specially versatile.
Many of these controls are common to most oscilloscope; a brief description below;
Power ans Scale Illumination control: Turns instrument on and controls illumination.
Focus control: Focus the spot or trace on the screen.
Intensity control: Regulates the brightness of the spot or trace.
9.
10. front-panel controls of oscilloscope are divided into four main
groups — the horizontal and vertical controls, input controls and
the triggering controls.
the horizontal controls of the oscilloscope allow users to adjust
the display’s horizontal scale. This section includes the control for the
horizontal delay (offset) as well as the control that indicates the time
per division on the x-axis.
the oscilloscope’s vertical controls are generally located in a section
specifically marked Vertical. The controls found in this section allow
users to adjust the display’s vertical aspect, and include the control
that indicates the number of volts per division on the display grid’s y-
axis.
The trigger controls of the oscilloscope allow users to choose the
vertical trigger level as well as the desired triggering capability.
Common triggering types include glitch triggering, edge triggering and
pulse-width triggering.
11. Advantages & Usage
Applications of CRO
Voltage measurement
Current measurement
Examination of waveform
Measurement of phase and frequency
Uses of CRO
In laboratory, the CRO can be used as
It can display different types of waveforms
It can measure short time interval
In voltmeter, it can measure potential difference
12. Block Diagram
The following block diagram shows the general purpose CRO
contraction. The CRO recruit the cathode ray tube and acts
as a heat of the oscilloscope. In an oscilloscope, the CRT
produces the electron beam which is accelerated to a high
velocity and brings to the focal point on a fluorescent
screen. Thus, the screen produces a visible spot where the
electron beam strikes with it. By detecting the beam above
the screen in reply to the electrical signal, the electrons can
act as an electrical pencil of light which produces a light
where it strikes.
13. Digital Storage Oscilloscope
A digital storage oscilloscope (often abbreviated DSO) is
an oscilloscope which stores and analyses the signal digitally
rather than using analog techniques. The input analogue signal is
sampled and then converted into a digital record of the
amplitude of the signal at each sample time.
The basis of the DSO is its input circuitry that has to carry out the
conversion of the input analog signal into a digital signal, using an
analog to digital (A/D) converter.
14. Working Principle of Digital Storage Oscilloscope
The digital oscilloscope digitizes and stores the input signal
This can be done by the use of CRT (Cathode ray tube) and digital memory.
The digitization 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.
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.
: The converter uses the expensive flash whose resolution decreases
with the increases of a sampling rate.