বৃহস্পতিবার, ২৮ জুন, ২০১৮
বুধবার, ১০ জানুয়ারী, ২০১৮
TV Engineering Tour Report Updated
Electronics & Communication Engineering Discipline
Course No: ECE 3202
Course Title: Television Engineering Sessional.
Study tour report on Khulna BTV Substation.
|
Submitted To:
Md. Shamsul Alam Submitted By:
Associate Professor Kangkan Bhakta
ECE Discipline ID:130910
Khulna University. 3rd Year,1st Term
ECE Discipline
Abdullah Al- Mamun Bulbul Khulna University.
Lecturer
ECE Discipline
Khulna University.
Study Tour Report on Khulna BTV Substation.
Objectives:
1. To know the different types of television transmitter
2. T0 Know about TV signals transmission that holds the information of capturing and visualizing the TV programs.
3. To attain some practical knowledge about the working principle of a TV station.
4. To see the composite video signal and 625 lines of the composite signal separately.
5. To gather knowledge about the other necessary used machines for receiving and transmitting and their working procedure.
6. To know how a TV transmitter transmits and radiates signal for general viewers through television receiver
Introduction:
As the student of Khulna University in Electronics and Communication Engineering Discipline, we have the course titled “Television Engineering” in 3rd year. Therefore, for the purposes of practical observation of the course titled “Television Engineering Sessional”, we get the opportunity to visit the Television station. The main TV station of our country is situated in Dhaka, Bangladesh. Therefore, we have visited the TELEVISION substation, Khulna on 17th November 2016, which situated in Khalishpur, Khulna 10 km away from Khulna University with all of our classmates and our honorable course teachers S.M. Shamsul Alam (Associate Professor) and Abdullah Al Mamun Bulbul (Lecturer) of Electronics and Communication Engineering Discipline. It is to be noted here that this Television Center has been playing a vital role in Broadcasting throughout the country.
Basic Structure and Operating Principles of Khulna TELEVISION Substation:
1. Signal reception & transmission
2. Modulation modules
3. Amplifier Section
4. Mixing Technique
5. Transmission System
6. Power System
Transmitter :
Khulna BTV Substation has 2 transmitters.
1. One analog transmitter Model No : TAV2 10KOA DDB3( THALES)
2. One digital Transmitter Model No : AXERA Solid State Transmitter.
Signal Reception & Transmission:
For the signal transmission, the coverage area of the substation is about 100 km (radius of the circle) as the capacity in Khulna zone. Both sound signals & picture signals are received clearly by the Television within 80 Km range.
The Transmitting power for coverage area is about 10 KW and has the effective radiated power of 96 KW. The supporting tower for the signal reception in Khulna TELEVISION substation earlier was BTCL (Bangladesh Telecommunications Company Limited), Khulna with the height of 500 ft and the height of the antenna is 15 ft, which has a gain of 9.6 dB but recently has launched the new dish and fully depend on Satellite Link. The Satellite Link used mostly for the better Reception & Transmission of signals. Some information about those links are given below:
Satellite Link:
There are three orbital deviations in the whole world for the satellites which are Leo (used for lower communication), Meo(used for mobile communication)and Geo(used in TELEVISION signals Transmission and reception).TheGeo has 3 (three) regions in the world which are Indian ocean zone, Pacific ocean zone, and Atlantic ocean zone. Our TELEVISION station named BTV (BangladeshTelevision) uses Indian Ocean zone. The name of BTV’s satellite is ASIASAT 3S. Its orbital location is 105.5 degrees east which is orbiting the world 36000km away from the ground.
Microwave Link:
Khulna TV substation mainly receives the signal 216 MHz to 223MHz from Jessoresubstation. This substation receives two types of signal, one is AM signal of about 222.75 MHz, which used for video information in TV and the other is FM signal of about 217.25 MHz, which is used for audio information in TV. Both signals are mixing by a multiplexer and then radiate the signal on air by the antenna. Khulna TV Substation doesn’t receive the original signal sent from Rampura Television Centre. In the following figure, I just tried to sketch a connection link between Rampura to Khulna via different substations
Rampura (Mother station)>>Romna>>Manikgonj>>Magura>>Jessore>> Khulna Substation
Modulation:
Two types of modulation occur in the substation.Those are audio modulation and video modulation. Several electrical and mechanical instruments are responsible for both types of modulations. An electrical machine named ‘THELES’ mainly controls the transmission section of modulation unit in Khulna TV Substation.It installed in Khulna substation in the year, 2005. It uses Band-3 Transmission with the Transmission power of 10KW.Two types of modulation in Khulna TV station discussed on the following –
Video Modulation:
In AM transmitters where efficiency is the prime requirement, amplitude modulation is effected by making the output current of a class C amplifier proportional to the modulating voltage. On the other hand, in an AM transmitter, amplitude modulation can be generated at any point after the crystal oscillator. From the transmitter section of Khulna TV substation, the output signal goes to “power amplification section” where rectification of amplitude modulating the signal at 557 MHz happens in many stages. The stage for the video signal is about 38.4 MHz.
Audio Modulation:
We know that at the transmitter, the audio signal isFrequency Modulated and it transferred to assigned channel sound carrier frequency by the use multiplies.In the Khulna TV substation, the IF stage for the audio signal is 34.4 MHz. Though the ‘THELES’ performs both analog system & digital modulation in TV system, there are also two more electrical machines as the transmission section of Khulna TV substation. One is NEC and the other is AXCERA. The NEC is the product of Nippon Electronics of Japan, which used in Khulna Television Substation before the year of 2005. It is tube type transmitter and needs a 400KW power supply to operate.But it is not more efficient than previous TV transmitter THELES. The other one named AXCERA, made by America is the new one, which installed in the substation in 2009. It supports the digital transmission. Now, it is developing its activity for the new Govt. channel ‘Sangsod Bangladesh’ in Bangladesh through Khulna TV substation.
Mixing:
The audio and video signals are both multiplexing through the machinery in a constructive way. The machine is called the De-multiplexer. It has two input section and one output section.The output section sections is joined to the transmission line
Transmission:
After mixing the AM and FM signals by the de-multiplexer machine path from the machine is constructed to transmit the mixed signal.The antenna through the transmission line transmits the mixed signal. That transmission equipment placed outside of the TV substation. Some practical information of antenna and transmission line.
Antenna:
The main antenna of the substation called Dipole antenna, which is Omnidirectional. Its general height is 15ft, which placed on the top of a 500ft high tower on the ground. The antenna power is about 10kw for visual sync peak output. The gain of the antenna is about 9.6 dB. For the better receiving of signals by the TV set, there must have a Yagi-Uda antenna on the roof or open place of the building that is called directional antenna.
Composite video signal
|
The composite video signal as seen from the substation is given here. We were not allowed to use any camera, otherwise, genuine photos could be attached to this report. As seen from the figure, there is a pair of signals for two frames taken per steel picture.
Transmission Line
Wave-guided lines or Coaxial cables mainly develop the Transmission Line.The ground coil of the transmission line is 500ft.Within it, only 3ft is used for the ground level to save Arial from thundering. The special setup Austin transformer needed to light the neon light up above the aerial. It transmits the signal that can receive fairly from 90 miles so far, have also the radiation effect around the aerial.
Conclusion
The overall system of the Khulna TV substation corresponds to our theoretical knowledge. But some additional system and their working procedure I have learned through this tour. So this tour has helped me so much to understand the basic operation of the transmitting and receiving procedure of TV signals.So we are thankful to our course teachers for arranging such a tour and also the instructors form the Television Center. It will help us surely in the long run when we will want to work in this particular field.
Television Engineering Sessional Tour Report 2016
Report on Study Tour Of Khulna Television Substation
Course Title: Television Engineering Sessional.
Course No: ECE-3202.
Date of the Tour: 12th November 2016.
Date of Report Submission: 20th November 2016.
Submitted To
S.M. Shamsul Alam
(Associate Professor)
ECE Discipline
Khulna University, Khulna.
&
Md. Abdullah-Al-Mamun Bulbul
ECE Discipline
Khulna University, Khulna.
Submitted By:
Kangkan Bhakta
ID: 130910
3rd Year, 2nd Term
ECE Discipline
Khulna University, Khulna.
Title: Study Tour in Khulna Television Substation.
Introduction
As the student of Khulna University in Electronics and Communication
Engineering Discipline, we have the course titled “Television Engineering” in 3rd year.Therefore, for the purposes of practical part of the course titled “Television Engineering Sessional”, we get the opportunity to visit the Television station. Television station means where the basic television signals are transmitting and receiving through various equipment and machinery. The main TV station of our country is situated in Dhaka, Bangladesh. Therefore, we have visited the TV substation, which situated in Khulna located at khalishpur 10 km away from Khulna University with all of our classmates and our honorable course teachers.
Objectives
The main objectives of our tour include the practical knowledge on TV signal
transmitting that holds the information of capturing and visualizing the TV programs.
Our tour also includes the technique of LIVE telecasting on TV by receiving the signals from the main station (Dhaka). We can call the Khulna TV Substation as “TV
Transmitting Centre” which has both the entire transmitter and receiver systems.
Though the transmitter and receiver systems have no modern technical equipment but
they are working without any trouble with good performances.
Basic Structure and Operating Principles of Khulna TV Substation
Signal Reception & Transmission
Modulation Modules
Amplifier Section
Mixing Technique
Power system
Transmission System
Signal Reception & Transmission
For the signal transmission, the coverage area of the substation is about 100 km (radius of the circle) as the capacity in Khulna zone. Both sound signals & picture signals are received clearly by the TV set within 80 Km range. Full range of the signal transmission power is not normally used. The Transmitting power for coverage area is about 10 KW and has the effective radiated power of 96 KW. The supporting tower for the signal reception in Khulna TV substation is BTCL (Bangladesh Telephone Company Limited), Khulna with the height of 500 ft and the height of the antenna is 15 ft, which has a gain of 9.6 dB. There are two ways or links for the signal reception & transmission in Khulna TV substation.Those are Satellite Link & Microwave Link. The Satellite Link used mostly for the better Reception & Transmission of signals. Some information about those links are given below -
Satellite Link
There are three orbital deviations in the whole world for the satellites which are Leo (used for lower communication), Meo (used for mobile communication)and Geo(used in TV signals Transmission and reception).The Geo has 3 (three) regions in the world which are Indian ocean zone, Pacific ocean zone, and Atlantic ocean zone. Our TV station named BTV (Bangladesh Television) uses Indian Ocean zone. The name of BTV’s satellite is ASIASAT 3S.Its orbital location is 105.5 degrees East which is orbiting the world 36000km away from the ground.
Microwave Link
The Khulna TV substation mainly receives the signal 216 MHz to 223 MHz which means 7 MHz Bandwidth signal from the Jessore substation.Its channel number is 11 (eleven). The substation receives two types of signal, one is AM signal of about 222.75 MHz that used for video information in TV, and another one is FM signal of about 217.25 MHz, which used for audio information in TV. The both received signals are mixing through a demultiplexer machine and then transmit that mixed signal on air by the antenna.
We know that Khulna substation does not get the direct signal from the origin, Dhaka TV station that situated in Rampura. The basic paths for transmitted signals from Dhaka TV station to the Khulna TV substation can be represented by the following block diagram –
From the block diagram, we see that the signal first generated from Dhaka (Rampura)
TV station.Then it firstly received and then transmitted by some substations. Those
substations are Manikganj substation, Faridpur substation, Magura substation, Jhinaidah substation & Jessore substation. At last, the transmitted signal from Jessore substation received by Khulna substation. Those signals transmitted to Sathkira substation. The Sathkhira TV substation and Khulna TV substation uses the same signals. It’s known that the signal transmission and reception depend on the law of “eyesight”.
Modulation
Two types of modulation occur in the substation.Those are audio modulation and video modulation. Several electrical and mechanical instruments are responsible for both types of modulations. An electrical machine named ‘THELES’ mainly controls the transmission section of modulation unit in Khulna TV Substation. It is an air-cooled solid state DD (double drive) device. It installed in Khulna substation in
the year, 2005. It uses Band-3 Transmission with the Transmission power of 10KW.
The exiting section of the transmitter is 2 (two) types such as A-exciter and B-exciter. Every type exciter has 5 (five) modules. Two types of modulation in Khulna TV station discussed on the following -
DHAKA
(RAMPURA)
Station
MANIKGANJ
Substation
KHULNA
Substation
JESSORE
Substation
JHINAIDAH
Substation
MAGURA
Substation
FARIDPUR
Substation
SATHKIRA
Substation
Video Modulation
In AM transmitters where efficiency is the prime the requirement, amplitude modulation is effected by making the output current of a class C amplifier proportional to the modulating voltage. On the other hand, in an AM transmitter, amplitude modulation can be generated at any point after the crystal oscillator. From the transmitter section of Khulna TV substation, the output signal goes to “power amplification section” where rectification of amplitude modulating the signal at 557 MHz happens at any stage. The IF stage for video signal is about 38.4 MHz
Audio Modulation
We know that at the transmitter, the audio signal is Frequency Modulated and it transferred to assigned channel sound carrier frequency by the use of multipliers. It later amplified through several stages of power amplifiers to raise the power output to the desired level. Audio monitors are provided at various points to keep a check on the sound quality. In the Khulna TV substation, the IF stage for audio signal is 34.4 MHz
Though the ‘THELES’ performs both analog system & digital modulation in TV system,
there are also two more electrical machines as the transmission section of Khulna TV
substation. One is NEC and the other is AXCERA. The NEC is the product of Nippon
Electronics of Japan, which used in Khulna Television Substation before the year of 2005.
It is tube type transmitter and needs a 400KW power supply to operate.But it is not more efficient than previous TV transmitter THELES. The other one named AXCERA, made by America is the new one, which installed in the substation some months ago. It supports the digital transmission. Now, it is developing its activity for the new Govt. channel ‘Sangsod Bangladesh’ that will be launched soon in Bangladesh through Khulna TV substation.
Amplifier
In the TV substation, the name of the transmitter is THELES (model number: TAV210K0ADDB3) which is made in France. This transmitter follows the heterodyne action. It has 10 amplifiers. The 1st and 10th amplifier used for audio amplification.
They need the power of 1KW for audio transmission. The 2nd to 9th amplifiers used for video amplification. Those amplifiers need 1.25KW for visual transmission. In case of trouble, number four amplifier is missing in the transmitter without creating any problem in the total transmission system.
Mixing
We have discussed previously this section in the signal reception and
transmission section. In this section, the audio and video signals are both multiplexing
through the machinery in a constructive way. The machine is called the Demultiplexer. It has two input section and one output section.The output section sections are joined to the transmission line. The valuable cooling system is needed for the machine to work properly always to continue the signal transmission on the air through the transmission links.
Transmission
After mixing the AM and FM signals by the de-multiplexer machine a path from the machine is constructed to transmit the mixed signal. The path is made of high-quality steel to close the occurrences of errors in line. The antenna through the transmission line transmits the mixed signal. Those transmission equipment placed outside of the TV substation. Some practical information of antenna and transmission line given below –
Antenna
The main antenna of the substation called Dipole antenna, which is Omnidirectional. Its general height is 15ft, which placed on the top of a 500ft high tower on the ground. The antenna power is about 10kw for visual sync peak output. The gain of the antenna is about 9.6 dB. For the better receiving of signals by the TV set, there must have a Yagi-Uda antenna on the roof or open place of the building that is called directional antenna.
Transmission Line
Wave-guided lines or Coaxial cables mainly develop the Transmission Line. They have 28000 volts for proper transmission. The ground coil of the transmission line is 500ft.Within it, only 3ft is used for the ground level to save Arial from thundering. The special setup Austin transformer needed to light the neon light up above the aerial. It transmits the signal that can receive fairly from 90 miles so far, have also the radiation effect around the aerial.
To absorb all types of vibration in the line some materials such as raw cooler and
pretext type cover used surrounding all the walls at studios, booths, and the control room.
Power system of TV substation
Two powers suppliers one is National Grid maintains the main power system of the Khulna TV substation and other is Commercial Grid.The national grid controlled by Power Development Board (PDB).It supplies 11KV continuously to the station. If it fails suddenly then the substation has other option to maintain all transmission works simultaneously and that is the Generator of same power 11KV. The generator placed on the ground floor of the substation building. Here, the following block diagram shows the whole power system of the Khulna TV substation.
Observation
We will say in our observation that it is a great achievement for us to visit a TV substation lively. Mainly, it helps us to know about the practical and actual background of the Television broadcasting in an area of a country. With this successful TV tour, we achieve great experiences so that in future it will encourage us most to know more about the modern and advanced TV broadcasting systems. It is real that in our country the modern and advanced technologies are not available in all substations as like Khulna TV substation. However, we have seen that a new digital transmission machine in there which is not properly installed. We get the information that it will be joined with other transmission machines soon for the channel ‘Sangsod Bangladesh’. Then the people of Khulna will enjoy the digital TV system at home.
Conclusion
At last, it’s really a pleasure for us to get an opportunity to make such an amazing educational tour and complete all the works of it successfully.In this stage, we
will give thanks to our honorable course teachers. In addition, especially thanks to the
authority of Khulna TV substation to give us that good opportunity to complete the tour. The assistant engineer of the substation who gives us all the pieces of information and data that we should need to know for the tour. We will give thanks to the police super of Khulna Thana to give them permission to visit the substation.
National grid
11 KV
Step down
transformer
400V
Power factor
Improvement plant
Regulated power supply input
of Thales
রবিবার, ৭ জানুয়ারী, ২০১৮
শুক্রবার, ৫ জানুয়ারী, ২০১৮
Biomed my presentation
Biomedical Engineering
Electro Cardiogram
1 ECE Discipline 1/5/2018
ECG Signal Generation and Heart Bit
Calculation:
Submitted To:
Engr. Dr. Md. Maniruzzan Submitted By:
Professor Kangkan Bhakta
ECE Discipline ID: 13 09 10
Khulna University 4th Year, Tarm:II
ECE Discipline
Khulna University.
2 ECE Discipline 1/5/2018
Outlines:
What is ECG signal?
Why we need ECG signal?
Heart rate calculations.
How it works?
MATLAB code of ECG signal.
3 ECE Discipline 1/5/2018
What is ECG signal?
Electrocardiography (ECG or EKG) is the process of
recording the electrical activity of the heart over a period of
time using electrodes placed on the skin. These electrodes
detect the tiny electrical changes on the skin that arise from
the heart muscle's electro physiologic pattern
of depolarizing and repolarizing during each heartbeat. It is a
very commonly performed cardiology test.
4 ECE Discipline 1/5/2018
Why we need ECG signal?
Suspected myocardial infarction (heart attack) or new chest
pain
Suspected pulmonary embolism or new shortness of breath
A third heart sound, fourth heart sound, a cardiac murmur or
other findings to suggest structural heart disease
Perceived cardiac dysrhythmias either by pulse or palpitations
Monitoring of known cardiac dysrhythmias
Fainting or collapse.
Seizures
Monitoring the effects of a heart medication (e.g. drug-
induced QT prolongation).
5 ECE Discipline 1/5/2018
Heart Bit Calculations:
To determine heart bit we will use Karvonen method:
Calculate your maximum heart rate (Hrmax):
Multiply your age by 0.7 , then subtract the result from 207.
Example: If your age is 39 then , 207 – 39*0.7 = 180 bpm
Checking your resting heart rate ( RHR):
Watch a clock with a second hand and count the number of heart
beats in 30 seconds, starting with "zero" on the first heartbeat.[5]
Multiply the count by 2 to get your resting heart rate in
beats per minute.
6 ECE Discipline 1/5/2018
Heart Bit Calculation:
For greater accuracy, find the average from three different
mornings. For example, if you measure 62, 65, and
63 bpm, the average is (62 + 65 + 63) / 3, or about 63 bpm
RHR.
Calculate your Heart Rate Reserve (HRR):
To get your HRR, HRMax - RHR = HRR
180 – 63 = 117 bpm
Calculate your Target Minimum Heart Rate (Target HRMin).
Multiply your HRR by 0.5
117*0.5 = 58.5 bpm.
7 ECE Discipline 1/5/2018
How it works?
Introduction to ECG measurement system
The ECG system is shown on Figure 1. The ECG system
comprises four stages, each stage is as following:
(1) The first stage is a transducer—AgCl electrode, which convert
ECG into electrical voltage. The voltage is in the range of 1 mV ~
5 mV.
(2) The second stage is an instrumentation amplifier (Analog
Device, AD624), which has a very high CMRR (90dB) and high
gain (1000), with power supply +9V and -9V.
(3) We use an opto-coupler (NEC PS2506) to isolate the In-Amp
and output.
(4) After the opto-coupler is a bandpass filter of 0.04 Hz to 150
Hz filter. It’s implemented by cascading a low-pass filter and a
high pass filter.
8 ECE Discipline 1/5/2018
How it works?
9 ECE Discipline 1/5/2018
How it works?
ECG Signal
The basic structure of the heart is shown on Figure 2.
Measuring at different region of the heart will retrieve
different bio potential.
10 ECE Discipline 1/5/2018
The cardiac mechanism of ECG is shown on Figure 4. In
the top figure, the electrocardiogram (ECG) initiates the
cardiac cycle. The cardiac sounds are also shown. The
bottom figure shows that ejection occurs when the pressure
in the left ventricle exceeds that in the arteries.
Once the electrodes convert the ECG into electrical voltage,
these voltage can be fed into an instrumentation amplifier,
and then be processed.
11 ECE Discipline 1/5/2018
Figure 4 The ECG cardiac cycle.
We measure the ECG by connecting two electrodes on the right
and left chest respectively, as shown on Figure 5. The body should
be connected to ground of the circuits, so that we connect the leg
to the ground. If the body is not grounded, no signal would be
obtained.
12 ECE Discipline 1/5/2018
How it works?
13 ECE Discipline 1/5/2018
MATLAB Code Implementation:
Now we will investigate the ECG signal through MATLAB
code, Let’s see!
14 ECE Discipline 1/5/2018
Video tutorials for ECG measurement
15 ECE Discipline 1/5/2018
ECG Animation
16 ECE Discipline 1/5/2018
17 ECE Discipline 1/5/2018
Electro Cardiogram
1 ECE Discipline 1/5/2018
ECG Signal Generation and Heart Bit
Calculation:
Submitted To:
Engr. Dr. Md. Maniruzzan Submitted By:
Professor Kangkan Bhakta
ECE Discipline ID: 13 09 10
Khulna University 4th Year, Tarm:II
ECE Discipline
Khulna University.
2 ECE Discipline 1/5/2018
Outlines:
What is ECG signal?
Why we need ECG signal?
Heart rate calculations.
How it works?
MATLAB code of ECG signal.
3 ECE Discipline 1/5/2018
What is ECG signal?
Electrocardiography (ECG or EKG) is the process of
recording the electrical activity of the heart over a period of
time using electrodes placed on the skin. These electrodes
detect the tiny electrical changes on the skin that arise from
the heart muscle's electro physiologic pattern
of depolarizing and repolarizing during each heartbeat. It is a
very commonly performed cardiology test.
4 ECE Discipline 1/5/2018
Why we need ECG signal?
Suspected myocardial infarction (heart attack) or new chest
pain
Suspected pulmonary embolism or new shortness of breath
A third heart sound, fourth heart sound, a cardiac murmur or
other findings to suggest structural heart disease
Perceived cardiac dysrhythmias either by pulse or palpitations
Monitoring of known cardiac dysrhythmias
Fainting or collapse.
Seizures
Monitoring the effects of a heart medication (e.g. drug-
induced QT prolongation).
5 ECE Discipline 1/5/2018
Heart Bit Calculations:
To determine heart bit we will use Karvonen method:
Calculate your maximum heart rate (Hrmax):
Multiply your age by 0.7 , then subtract the result from 207.
Example: If your age is 39 then , 207 – 39*0.7 = 180 bpm
Checking your resting heart rate ( RHR):
Watch a clock with a second hand and count the number of heart
beats in 30 seconds, starting with "zero" on the first heartbeat.[5]
Multiply the count by 2 to get your resting heart rate in
beats per minute.
6 ECE Discipline 1/5/2018
Heart Bit Calculation:
For greater accuracy, find the average from three different
mornings. For example, if you measure 62, 65, and
63 bpm, the average is (62 + 65 + 63) / 3, or about 63 bpm
RHR.
Calculate your Heart Rate Reserve (HRR):
To get your HRR, HRMax - RHR = HRR
180 – 63 = 117 bpm
Calculate your Target Minimum Heart Rate (Target HRMin).
Multiply your HRR by 0.5
117*0.5 = 58.5 bpm.
7 ECE Discipline 1/5/2018
How it works?
Introduction to ECG measurement system
The ECG system is shown on Figure 1. The ECG system
comprises four stages, each stage is as following:
(1) The first stage is a transducer—AgCl electrode, which convert
ECG into electrical voltage. The voltage is in the range of 1 mV ~
5 mV.
(2) The second stage is an instrumentation amplifier (Analog
Device, AD624), which has a very high CMRR (90dB) and high
gain (1000), with power supply +9V and -9V.
(3) We use an opto-coupler (NEC PS2506) to isolate the In-Amp
and output.
(4) After the opto-coupler is a bandpass filter of 0.04 Hz to 150
Hz filter. It’s implemented by cascading a low-pass filter and a
high pass filter.
8 ECE Discipline 1/5/2018
How it works?
9 ECE Discipline 1/5/2018
How it works?
ECG Signal
The basic structure of the heart is shown on Figure 2.
Measuring at different region of the heart will retrieve
different bio potential.
10 ECE Discipline 1/5/2018
The cardiac mechanism of ECG is shown on Figure 4. In
the top figure, the electrocardiogram (ECG) initiates the
cardiac cycle. The cardiac sounds are also shown. The
bottom figure shows that ejection occurs when the pressure
in the left ventricle exceeds that in the arteries.
Once the electrodes convert the ECG into electrical voltage,
these voltage can be fed into an instrumentation amplifier,
and then be processed.
11 ECE Discipline 1/5/2018
Figure 4 The ECG cardiac cycle.
We measure the ECG by connecting two electrodes on the right
and left chest respectively, as shown on Figure 5. The body should
be connected to ground of the circuits, so that we connect the leg
to the ground. If the body is not grounded, no signal would be
obtained.
12 ECE Discipline 1/5/2018
How it works?
13 ECE Discipline 1/5/2018
MATLAB Code Implementation:
Now we will investigate the ECG signal through MATLAB
code, Let’s see!
14 ECE Discipline 1/5/2018
Video tutorials for ECG measurement
15 ECE Discipline 1/5/2018
ECG Animation
16 ECE Discipline 1/5/2018
17 ECE Discipline 1/5/2018
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