Hajee Mohammad Danesh Science and Technology University (HSTU)
Course Name – Industrial Tour
Submitted By – Nishat Sheema
ID -2002128
Level 2 Semester – II
B.Sc. (Engg) in ECE
Submitted To – Md. Abubakar Siddik
Assistant Professor, Dept. Of Electronics & Communication Engineering
Date of submission -30 -08-2023
Industrial tour
In 2023, a trip of an industrial facility is planned by the Department of Electronics
and Communication Engineering (ECE) Level 2. Our tour was guided by lecturer
Md. Selim Hossain, lecturer Md. Kamal Hossain, and assistant professor Md.
Abubakar Siddik.Our esteemed teacher gave us a lot of assistance in making the
special arrangements needed to make the tour successful.
Timeline :
Date :21 August ,2023.
Place : Thakurgaon.
First Visit : BTV Sub-station , Thakurgaon.
Second Visit : Bangladesh Beter, Thakurgaon.
Start Time : 9:40 AM.
End Time : 6:30 PM.
Total Student : 66.
RADIO STATION
Introduction :
In Industrial tour we are visited two industrial area - BTV Sub-station , Thakurgaon
, Bangladesh Beter, Thakurgaon . And learn about many industrial things.
Voltage Stabilizer:
It is an electrical appliance that, despite fluctuations in the input or incoming supply
voltage, is made to produce a constant voltage to a load at its output terminals. It
guards against voltage surges, overvoltage’s, and undervoltage for the machinery or
equipment.
The automated voltage regulator (AVR) is another name for it. To shield expensive
and priceless electrical equipment from dangerous low/high voltage swings, voltage
stabilizers are preferred. Air conditioners, offset printing machines, laboratory
equipment, industrial machinery, and medical equipment are a few of these items.
Radio Station:
A broadcasting chain is maintained by radio stations. IRD (Integrated Receiver
Decode) was utilized by the radio station to receive the signal. IRDs are electronic
devices that are used to capture radio frequency signals and transform the digital
information they carry. station of radio Send a speech signal first using a
microphone. Signal from the microphone is sent to the input console. The signal is
then sent to the computer by the console. The signal is then computer-encoded and
transmitted via the transmitter on the tower.
For radio transmission, a radio station has two studios. Top studio and music studio
are such.On-air system for the music studio.
Sometimes the signal does not enter the transmitter immediately. It creates a path
from transmitter through the patch.
CIRCUIT BREAKER:
Circuit breakers are the tools used to create and interrupt electrical circuits based on
predetermined conditions. A circuit breaker serves the following purposes:
1. It must turn on quickly and sustain extended currents at full load.
2. It must automatically open to disconnect the load in the event of an overload under
predetermined circumstances.
3. It must swiftly stop the large current, which could flow in any area of the system
in the event of a short circuit.
4. The circuit breaker must be able to withstand the heat conditions and the impact
of arcing at its contact.
Radio station power supply:
The equipment used to start and stop a radio station contains a 1100-volt power
source and a large emergency generator. Two days' worth of backup power is
provided by the generator. The transmitter then makes use of the same tower that the
BTV's substation utilized.
AM Signal Transmission:
Communication systems employ the modulation technique known as amplitude
modulation (AM) to convey information by modulating the amplitude of a carrier
signal.
Message signal:
The signal that contains the actual information to be communicated is referred to as
the information signal, also known as the modulating signal. Typically, this signal is
an audio signal with a lower frequency.
Carrier Signal:
The information is sent using a high-frequency sinusoidal waveform known as the
carrier signal. Usually, it operates at a frequency that is significantly higher than the
frequency of the information signal.
Modulating signal :
In the AM method, the carrier signal's amplitude is modulated to match the
information signal's amplitude changes. The carrier amplitude increases when the
information signal amplitude is high, and it decreases when the information signal
amplitude is low.
Transmission:
The AM modulated signal is then broadcast via antennas over the air. The carrier
frequency and two sidebands on either side of the carrier, which represent the
positive and negative frequency variations brought on by the modulation process,
make up the frequency spectrum that the modulated signal .
Fm Signal Transmission:
By changing the frequency of a carrier signal in accordance with changes in the
amplitude of the information signal, frequency modulation, also known as FM, is a
modulation technique used in communication systems to transfer information. Radio
broadcasting and other communication applications frequently use FM transmission.
Message Signal :
The signal that carries the actual information to be communicated is known as the
information signal, sometimes known as the modulating signal. In FM,
modifications in the information signal's amplitude result in adjustments in the
carrier signal's frequency.
Carrier Signal :
The carrier signal in FM is likewise a high-frequency sinusoidal waveform. The
frequency of the information signal is selected to be significantly lower than that of
the carrier.
Modulation:
In contrast to AM, which modifies the carrier signal's amplitude, FM modifies the
carrier signal's frequency. When the information signal's amplitude rises, the carrier
frequency rises as well, and when its amplitude falls, the carrier frequency falls. The
FM modulated signal is the end product of FM modulation. Based on changes in the
amplitude of the information stream, the carrier frequency of this signal oscillates
above and below its core frequency.
Bandpass filter :
A bandpass filter is an electrical circuit or device that attenuates frequencies outside
of a specific frequency range while allowing frequencies within that range to pass
through. It is frequently utilized in many different applications, including audio
equipment, communication systems, signal processing, and more. A bandpass filter's
operation requires the selective transmission of a certain frequency range.
A bandpass filter only allows high frequency signals to pass. The bandpass filter
filters the signal after it has been broadcast.
Dummy Load:
Sometimes they send the signal to the dummy load first, then disseminate it. It has a
10 kilowatt output and is used for testing. When a device produces 10 kw of output
after receiving signals as input, the signal can be considered completely prepared for
transmission via a feeder cable.
The feeding cable is connected to a dehydrator. if the feeder cable has any wind or
moisture. The feeder cable is made moisture-free by the de-hydrator, which also
cleans them.
Radio Antenna :
A radio station converts the radio frequency it produces into electromagnetic waves
using an antenna in order to send its broadcast over great distances. It is possible to
transmit and receive electromagnetic radio waves using a radio antenna, which is a
specialized equipment that enables information to be transmitted over the airways.
In many communication systems, such as radio broadcasting, wireless
communication, and television transmission, antennas are essential.
Antenna size = λ/4
The approximate length of antenna is 76 meter. The antenna coverage range is 50
kilometer and radiates 999 KHz radio frequency. When transmitting, an electrical
signal containing information, such as audio or data, is applied to the antenna. This
signal is typically generated by a transmitter. The radiated electromagnetic waves
travel through space as radio waves. Their frequency is determined by the frequency
of the electrical signal applied to the antenna.
BTV
BTV sub-station:-
We arrived at Bangladesh Television, Thakurgaon, commonly known as BTV sub-
station, at 11:25 a.m. after a one and a half hour bus ride.
Our initial stop was at the BTV substation. The authorities of the BTV were very
helpful. We were shown to the machinery by one of their technical engineers.
First, he says this about BTV: "Bangladesh Television, often abbreviated BTV, is
the country of Bangladesh's state-owned television network. In its early years, the
network served as the East Pakistan division of PTV. It is the oldest Bengali-
language television network in the world, and is the sister of the radio broadcaster
Bangladesh Betar, which, along with BTV, are both owned and run by the
government.
The only television network in the nation is Bangladesh Television, which on a
terrestrial TV. The majority of its funding comes from television licensing fees.
Although it has created a number of award-winning programs, it has frequently been
criticized for serving as the government's mouthpiece and their lack of high-quality
content. Bangladesh Television's corporate office and administrative building are
both situated in Rampura, Dhaka.
A Parabolic dish antenna was then visible in front of the BTV building. Our
instructor briefly discussed the parabolic dish antenna as a receiver.
Parabolic Dish Antenna :-
A directional antenna commonly used for sending and receiving radio signals, such
as those for communication, satellite communication, radar, and radio astronomy, is
a parabolic dish antenna, also known as a parabolic antenna or dish. Its unique
characteristic is its parabolic form, which enables it to concentrate incoming or
outgoing electromagnetic waves into a single point, or focal point.
A parabolic dish antenna's basic design comprises of several essential elements:
Parabolic Reflector:
The parabolic reflector is the antenna's most noticeable component. It is a concave,
curving surface with a parabola-like shape. Incoming parallel electromagnetic waves
are intended to be focused into a single focal point by this shape. To achieve effective
reflection, the reflective surface is often constructed of metal, such as aluminum, and
is highly polished.
Feed Antenna:
The feed antenna, a tiny antenna component at the center of the parabolic reflector,
is in charge of sending and receiving signals. It is positioned carefully to make sure
that the reflector will properly direct the electromagnetic waves onto it. The feed
antenna might be of several types, such a horn or a dipole.
Support Structure:
A mounting support holds the parabolic reflector in place and ensures that it is
correctly positioned. This framework may consist of an arrangement of arms, struts,
and a mount that enables the dish to be adjusted or oriented in a specific direction
for the best signal reception.
Feed System:
This system includes the components responsible for connecting the feed antenna to
the receiver or transmitter. It might involve waveguides, coaxial cables, and other
transmission line elements to ensure a proper connection and minimal signal loss.
Functioning: When electromagnetic waves, such as radio or microwaves, hit the
parabolic reflector, they are reflected off the curved surface and focused onto the
feed antenna placed at the focal point. This focusing effect enhances the antenna's
gain, making it highly directional. As a result, the dish antenna is able to transmit or
receive signals with greater power and
sensitivity in a specific direction, compared to omnidirectional antennas.
The parabolic dish antenna's configuration enables it to have high gain, narrow
beamwidth, and low side lobes, making it ideal for long-distance communication,
point-to-point links, and precise radar applications. The dish's ability to concentrate
signals allows for improved signal strength.
In summary, a parabolic dish antenna's key features include its parabolic reflector,
feed antenna, support structure, and feed system. This configuration gives it the
ability to focus and direct electromagnetic waves for effective long-range
communication, radar, and other applications.
BTV Control Room: BTV has four channels .
1 . BTV .
2 . BTV world.
3 .BTV Chittagong.
4 . Sangsad TV
These four channels receive signal from satellite. The Bangabandhu satellite has 40
transponders. In which 14 transponders are used for C band and C band is usually
used for large disk.
On the other hand, next of the 26 bands are for Q band. But in Q band there can be
occurred some small delay.
When receiver receive the signal from the disk antenna. It send them to the patch
panel . In patch panel the signal gets decode and further process the signal. In a
patch panel there is 2 transmission channel such as AM and FM . The signal process
in a way that those signals can be transmitted either AM or FM.
Then the signal will be send into transmitter. In transmitter a carrier signal is added
to the original signal . Then there are 4 amplifiers for amplified the signal. Then
encoded the signal .The signal is ready to be sent in transmission antenna . The
transmission frequency range is 209 MHz to 216 MHz
Transmitter: A television transmitter is a device used to broadcast television signals
over the airwaves to be received by television sets and antennas. It converts video
and audio signals into electromagnetic waves that can travel through the air to be
picked up by antennas on television receivers. Here's a brief overview of how
television transmitters work:
1. Signal Encoding: Television content, including video and audio, is encoded
into electronic signals. These signals represent the visual and auditory
information of the television program.
2. Modulation: The encoded signals are then modulated onto a carrier
frequency. Modulation is the process of varying the properties of a carrier
wave (usually a radio frequency) in accordance with the input signal.
Common modulation techniques include amplitude modulation (AM) and
frequency modulation (FM).
3. Amplification: The modulated carrier signal is amplified to increase its
power. This amplification is necessary to ensure that the signal can cover a
wide area and overcome obstacles like buildings and terrain.
4. Antenna Transmission: The amplified signal is then fed into an antenna. The
antenna radiates the electromagnetic waves carrying the television signal into
the surrounding space. These waves propagate outward in all directions.
5. Reception: Television sets or antennas in the coverage area of the transmitter
receive these electromagnetic waves. The television receiver demodulates the
received signal, extracting the original video and audio signals.
6. Decoding and Display:The demodulated video and audio signals are decoded
and processed by the television set. The video signals are displayed on the
screen, while the audio signals are played through the speakers.Television
transmitters play a crucial role in broadcasting television content to homes
and other locations. They are an integral part of the infrastructure that enables
the distribution of television programs to a wide audience.It's worth noting
that with the advent of digital television (DTV), many countries have
transitioned from analog to digital broadcasting. Digital TV transmitters
encode signals using digital modulation techniques and offer several benefits,
including higher picture and sound quality, more efficient use of spectrum,
and additional features like electronic program guides and interactive content.
Dummy Load:
Sometimes they send the signal to the dummy load first, then disseminate it. It has a
10 kilowatt output and is used for testing. When a device produces 10 kw of output
after receiving signals as input, the signal can be considered completely prepared for
transmission via a feeder cable.
The feeding cable is connected to a dehydrator. if the feeder cable has any wind or
moisture. The feeder cable is made moisture-free by the de-hydrator, which also
cleans them.
Conclusion:
We had the opportunity to use a communication system in real life. We gained
knowledge of how various broadcast system components, such as the transmitter,
antenna, and modulator, operate. We discovered what a fantastic terrestrial channel
BTV is. In the music station, live music was being recorded.
We made the decision to visit Kantajew Temple after the instructional tours.So on
our way home, we stopped at Temple. We stayed there for almost 50 minutes before
leaving to go back to our institution. We were greatly assisted by our esteemed
supervisors in successfully completing the industrial tour.
