VIDEO CAMERA

VIDEO CAMERA

Base Theory
A video camera is a camera used for electronic motion picture acquisition, initially developed by the television industry but now common in other applications as well. The earliest video cameras were those of John Logie Baird, based on the electromechanical Nipkow disk and used by the BBC in experimental broadcasts through the 1930s. All-electronic designs based on the cathode ray tube, such as Vladimir Zworykin's Iconoscope and Philo T. Farnsworth's Image dissector, supplanted the Baird system by the 1940s and remained in wide use until the 1980s, when cameras based on solid-state image sensors such as CCDs (and later CMOS active pixel sensors) eliminated common problems with tube technologies such as burn-in and made digital video workflow practical.



Video cameras are used primarily in two modes. The first, characteristic of much early television, is what might be called a live broadcast, where the camera feeds real time images directly to a screen for immediate observation. A few cameras still serve live television production, but most live connections are for security, military/tactical, and industrial operations where surreptitious or remote viewing is required. The second is to have the images recorded to a storage device for archiving or further processing; for many years, videotape was the primary format used for this purpose, but optical disc media, hard disk, and flash memory are all increasingly used. Recorded video is used in television and film production, and more often surveillance and monitoring tasks where unattended recording of a situation is required for later analysis.
Modern video cameras have numerous designs and uses, not all of which resemble the early television cameras.
Professional video cameras, such as those used in television and sometimes film production; these may be studio-based or mobile. Such cameras generally offer extremely fine-grained manual control for the camera operator, often to the exclusion of automated operation.
Camcorders, which combine a camera and a VCR or other recording device in one unit; these are mobile, and are widely used for television production, home movies, electronic news gathering (including citizen journalism), and similar applications. Some digital ones are
Pocket video cameras.
Closed-circuit television (CCTV) cameras, generally used for security, surveillance, and/or monitoring purposes. Such cameras are designed to be small, easily hidden, and able to operate unattended; those used in industrial or scientific settings are often meant for use in environments that are normally inaccessible or uncomfortable for humans, and are therefore hardened for such hostile environments (e.g. radiation, high heat, or toxic chemical exposure).
Webcams are video cameras which stream a live video feed to a computer. Larger video cameras (especially camcorders and CCTV cameras) can be similarly used, though they may need an analog-to-digital converter in order to store the output on a computer or digital video recorder or send it to a wider network.
Digital cameras which convert the signal directly to a digital output; such cameras are often small, even smaller than CCTV security cameras, and are often used as webcams or optimized for still-camera use. The majority are incorporated directly into computer or communications hardware, particularly mobile phones.
Special systems, like those used for scientific research, e.g. on board a satellite or a spaceprobe, or in artificial intelligence and robotics research. Such cameras are often tuned for non-visible radiation for Infrared photography (for night vision and heat sensing) or X-ray (for medical and video astronomy use).


Objectives:

1.1 Getting to know the video camera.
1.2 Measuring the composite video on a video camera.
1.3 Determining the parameters of composite video.


Equipment Used:

1 Video Camera
1 Oscilloscope 40 MHz and passive probe
An RCA cable connector - BNC (75 )


Circuit diagram:

Introduction:

A comprehensive idea of a TV camera function is depicted in Figure 3-2 and 3-3. In Figure 3-2 the camera is aimed at scene / view so that the optical image (optical image) can be focused on the target plate tube makers (pick-up tube). If you can look inside, you'll see the shadow-optical. The resulting video signal is shown by the oscilloscope waveform in the bottom left of the picture. Above is a monitor oscilloscope, which shows a reproduced image.

Figure 3-3. Block diagram that shows how to channel television camera output signal
Video komposit.Disini not shown reflection and focusing the camera tube.


Details of the video signal waveform which is more fully shown by the block diagram in Figure 3-3. At first, blanking pulses added to signal the camera. They cause the signal amplitude to the black levels so pengulangjejakan (retrace) the MRV will not be visible. Further alignment pulses (sync) is inserted. Alignment (synchronization) is required to set the time & MRV horizontal and vertical.
Camera signal with blanking and synchronization (sync) is called a composite video signal (composite video signal). Sometimes the term is not a composite video signal (noncompoxite video signal) is used to identify the signal with blanking camera but without alignment. Standard output level of the composite video signal from the camera is 1Vpuncak-to-peak (pp = peak to peak) with the alignment pulses in the down position for negative polarity.

Experimental Procedure

1. Set-up devices such as a picture he bag, connect the video camera out with input CRO.
2. ON the instrument.
3. Set the appropriate CRO to be easily observed (MODE on the TV-H position and / or TV-V).
When seeing a wave of horizontal synchronization MODE switch put on the TV-H position, while to see a wave of vertical synchronization MODE switch is placed vertically on the TV-V position.

4. Specify the synchronization pulses, blanking pulses, front and rear porch, and image information.

5. Image of the wave form and specify voltage.


Practical Results

1. Horizontal Image Mode (TV-H)



Fig. Composite Video to object Fig. Composite video for dark objects (black)
General

Fig. Sinc and enlarged color bearer

2. TV mode Picture-Vertical (TV-V)

Picture Mode TV-V

Picture Mode enlarged TV-V

Image Analysis

Conclusion

From the experimental results can be concluded that the composite signal comprises an analog video signal so that the formation of a variety of image information. The signal is the vertical synchronization signals and horizontal synchronization signals, balanking, front porch and rear, and the information signal itself.

PATTERN GENERATOR

PATTERN GENERATOR

Base Theory
General Description
A pattern generator is a very useful instrument for the correct alignment of the timing
circuits of a television set. The circuit we propose you to build, is a «bar generator» that
will produce horizontal and vertical stripes (bars) on the TV screen, that will help you align
the vertical and horizontal scanning synchronisation circuits of the receiver.




Technical Specifications - Characteristics 
Working voltage: ................... 9 VDC
Current drawn: ...................... 2 mA
Operating Frequency: ........... 170 - 250 MHz (VHF)
Horizontal scan frequency: ... 16525 Hz
Vertical scan frequency: ....... 50 Hz
Output impedance: ............... 75 ohm


How it Works
The circuit can be divided  in five different stages. Four astable multivibrators and the
output stage which is built around the VHF oscillator.
The first astable consists of two NOR gates in U2 and the components R9, R15, D4, C8,
and C10. The two NOR gates are used as inverters and  together they form an astable
multivibrator which oscillates at a frequency of 16525 Hz, which is the horizontal scan
frequency of the TV, and can be fine-tuned by means of R15. The capacitor C10 is there
to provide the necessary feedback to maintain the oscillations. The signal from the output
of the oscillator is taken through C8 and R6 to the output stage and modulates it.
The other multivibrator built around the other two NOR gates in U2, together with R12,
R14, D6 and C12 produces the necessary pulses for the vertical scanning frequency which
is 50 Hz. This frequency is fed to the input of one of the AND gates in U1 (pin 1).
The multivibrator built around two of the NOR gates in U3 and the components R13, R17,
C9 and D7 produces the pauses between pulses, which after being fed to the AND gates
in U1 (pins 8, 9 and 10) which are connected as inverters are then also used to modulate
the oscillator and appear on the TV screen as vertical stripes (bars).
Finally the last multivibrator which consists of the remaining two NOR gates in U3 together
with the components R1, R11, R16, C7 and D5 produces the pulses which appear on the
screen as horizontal lines.
All four multivibrators are based on the same operating principle. They are elementary
oscillators using NOR gates and a feed back element which is either a capacitor or a
resistor (depending on the operating frequency) and all of them incorporate a trimmer to
permit slight adjustments to their operating frequency.
The output signals from the three inverters in U1 are taken through D3, R7 and D2 to the
VHF oscillator. This is a common base circuit which has a low input resistance and relatively high voltage amplification. The output frequency of the oscillator is determined by the coil which is formed by the copper track on the PCB and the variable capacitor L1. This frequency is between 170 and 250 MHz and can be adjusted by the trimmer L1.
The resistors R1 and R2 form a potential divider which controls the modulation level of the
output oscillator and the trimmer R3 controls the contrast of the pattern against the back
ground.
Finally the transistor Q2 and its associated circuit (R2 and D1) form a voltage stabiliser for
the circuit. The trimmers R14, and R15 control the vertical and horizontal scan frequencies
respectively so that the image becomes steady and the squares on the screen appear
perfect. The trimmers R16 and R17 set the number of the horizontal and vertical bars
respectively.

Construction
First of all let us consider a few basics in building electronic circuits on a printed circuit
board. The board is made of a thin insulating material clad with a thin layer of conductive
copper that is shaped in such a way as to form the necessary conductors between the
various components of the circuit. The use of a properly designed printed circuit board is
very desirable as it speeds construction up considerably and reduces the possibility of
making errors. QUASAR Kit boards also come pre-drilled and with the outline of the
components and their identification printed on the component side to make construction
easier. To protect the board during storage from oxidation and assure it gets to you in
perfect condition the copper is tinned during manufacturing and covered with a special
varnish that protects it from getting oxidised and also makes soldering easier.
Soldering the components to the board is the only way to build your circuit and from the
way you do it depends greatly your success or failure. This work is not very difficult and if
you stick to a few rules you should have no problems. The soldering iron that you use
must be light and its power should not exceed the 25 Watts. The tip should be fine and
must be kept clean at all times. For this purpose come very handy specially made sponges
that are kept wet and from time to time you can wipe the hot tip on them to remove all the
residues that tend to accumulate on it. DO NOT file or sandpaper a dirty or worn out tip. If
the tip cannot be cleaned, replace it. There are many different types of solder in the market
and you should choose a good quality one that contains the necessary flux in its core, to
assure a perfect joint every time. DO NOT use soldering flux apart from that which is
already included in your solder. Too much flux can cause many problems and is one of the
main causes of circuit malfunction. If nevertheless you have to use extra flux, as it is the
case when you have to tin copper wires, clean it very thoroughly after you finish your work.
In order to solder a component correctly you should do the following:
- Clean the component leads with a small piece of emery paper.
- Bend them at the correct distance from the component’s body and insert the component
in its place on the board.
- You may find sometimes a component with heavier gauge leads than usual, that are too
thick to enter in the holes of the P.C. board. In this case use a mini drill to enlarge the
holes slightly. Do not make the holes too large as this is going to make soldering difficult afterwards.
- Take the hot iron and place its tip on the component lead while holding the end of the
solder wire at the point where the lead emerges from the board. The iron tip must touch
the lead slightly above the p.c. board.
- When the solder starts to melt and flow, wait till it covers evenly the area around the hole
and the flux boils and gets out from underneath the solder. The whole operation should not take more than 5 seconds. Remove the iron and leave the solder to cool naturally without
blowing on it or moving the component. If everything was done properly the surface of the
joint must have a bright metallic finish and its edges should be smoothly ended on the
component lead and the board track. If the solder looks dull, cracked, or has the shape of
a blob then you have made a dry joint and you should remove the solder (with a pump, or
a solder wick) and redo it.
- Take care not to overheat the tracks as it is very easy to lift them from the board and
break them.
- When you are soldering a sensitive component it is good practice to hold the lead  from
the component side of the board with a pair of long-nose pliers to divert any heat that
could possibly damage the component.
- Make sure that you do not use more solder than it is necessary as you are running the
risk of short-circuiting adjacent tracks on the board, especially if they are very close
together.
- When you finish your work, cut off the excess of the component leads and clean the
board thoroughly with a suitable solvent to remove all flux residues that may still remain on
it.

To build the pattern generator solder first of all the IC sockets on the P.C. board taking
care to insert them correctly and then make the jumper connections and solder the pins for
the external connections. Continue with the resistors and the capacitors, again making
sure that the electrolytic are inserted the right way round, and finally solder in place the
diodes and the transistors, taking care to avoid overheating them with the soldering iron.
Place the trimmers and the variable capacitor in their places and solder the battery clip’s
leads across the points marked (+) and (-), pins 4 and 1 respectively.
At this point make a very careful inspection of your work and if you are sure that everything
is OK take the IC’s from their aluminium wrap, which is there to protect their delicate
circuits from static discharges and insert them very carefully in their sockets. Be especially
careful in the process, to avoid touching the pins with your hands and also to avoid
bending them between the IC’s and the sockets.
To get the best performance from your generator it is highly recommended to enclose it in
a metal case which will shield all stray radiation that could possibly cause trouble in use. (If
you use a metal case the shielding of the output cable should be connected to the case by
means of a 5 or 10 pF ceramic capacitor). The generator can be connected to the TV set
under test either directly using a piece of coaxial cable connected between the points 3
(signal) and 2 (earth) of the circuit and the VHF antenna input of the receiver, or if the
receiver is sensitive enough and the instrument is not very far the connection by cable may
not be necessary because the transmitter section of the generator is quite powerful.

Adjustments 
- Connect the output of the generator by means of a coaxial cable with the input of your TV
receiver.
- Turn the receiver on and select a VHF channel (say ch. 5).
- Set R3 in the middle of its travel.
- Using a plastic tuning screwdriver adjust L1 till you get an image on the TV screen even if
it is distorted.
- Adjust R14 till the vertical stripes become more defined.
- Adjust R15 so that the horizontal stripes appear on the screen.
- By adjusting R16 and R17 select the number of horizontal and vertical stripes that will be displayed on the screen.
- Re-adjust R14 to make the horizontal stripes completely steady.
- Finally touch again R14, R15, R16, and R17 to get the best possible image definition and
set the image contrast by means of the trimmer R3.

Warning 
QUASAR kits are sold as stand alone training kits.
If they are used as part of a larger assembly and any damage is caused, our company
bears no responsibility.

While using electrical parts, handle power supply and equipment with great care, following
safety standards as described by international specs and regulations.

If it does not work 
Check your work for possible dry joints, bridges across adjacent tracks or soldering flux
residues that usually cause problems. 
Check again all the external connections to and from the circuit to see if there is a mistake
there.
- See that there are no components missing or inserted in the wrong places.  
- Make sure that all the polarised components have been soldered the right way round. -
Make sure the supply has the correct voltage and is connected the right way round to your
circuit. 
- Check your project for faulty or damaged components.

Schematic Diagram 

Objectives:

1.1 Getting to know the basic patterns in the Pattern Generator.
1.2 Measuring  standard composite video and voltage on each pattern.
1.3 Measuring modulated wave on modulator video (RF).
1.4 Measuring video IF.


Equipment that Used:

Pattern Generator TV signal, LODESTAR CPG-1367A                     1 pcs
Oscilloscope 40 MHz and passive probe                                            1 pcs
Power Supply                                                                                    1 pcs
cable connecting the BNC - BNC 75 W                                            1 pcs
BNC connector cable - RCA 75 W                                                   1 pcs

T-BNC Connector                                                                            1 pcs

Theory Platform:

The Source of image patterns ( on pattern generator) is the technique of video (television) for the purpose of setting up or finding fault. There are various kinds of image patterns with a variety of needs. Pattern of so many images that exist, there are several commonly used image patterns are not very specific uses.
Types of Image and its Use Patterns 

# spots (Dot)

To check and adjust the static convergence in the middle of the screen with a low brightness. This should be done according to the television manufacturer's instructions.

# The boxes (crosshach)

Plaid pattern with horizontal lines and vertical lines with the background color of black and white color line.
1. To check and adjust the horizontal and vertical dynamic convergence and the convergence an angle.

2. By linearity of deflection (deflection) the correct horizontal and vertical, horizontal white lines should be a rectangular equilateral.

If not, then the plane can be checked for truth response amplitudes. Vertical white line width should be 200 ns.

If this line is not sharp and visible lower intensity than the horizontal line, the amplitude response is possible recipient is not enough.

If vertical lines appear double, receiver circuit may be vibrating.

3. To pin-cushion proofreaders check the receiver. With the convergence of the right, square in the corner of the screen should be approximately equal to a square in the middle of the screen at a distance of normal vision.

# White (white)

This pattern contains a signal 100% white (no color information) with alternating burst.

1. Images for constant brightness on the entire screen (tida no hum, etc..)
2. Color picture tube for setting a good white (white-D).
3. Limitation of fire flow on the color picture tube.
4. For the video recorder is ideal pattern for the current setting of writing (recording) luminance. This pattern can also to set the FM demodulator (setting white level).

# Beam Color (color)

Blocks of colors (color bar) consists of 8 vertical color bar standard and a reference beam horizontally. Beams 8 colors are arranged in order of depreciation luminan. From left to right beams D color is white, yellow, cyan, green, magenta, red, blue, and black.
This pattern is used to set the operational control of the receiver at the correct position.
Horizontal beam (white level) on the bottom of this pattern is used as a standard when setting the amplitude signal of color differences with relationships with luminan signal in the picture tube. Signals can be used for resetting the signal amplitude of the demodulator circuit and the matrix, as the output can be compared with the reference beam. In addition to the above purposes, this pattern can be used to check the overall color appearance. So can also be used checks and settings on the receiver or VCR:
1. Lock Inspection burst.
2. AGC examination of color and which create the color.
3. Inspection circuit reactance of the subcarrier regenerator.
4. Examination of the regenerator subcarrier synchronization.
5. Checking circuit identifier (identification) PAL.

Signal Synchronization
Synchronization signal is a signal that is always given periodically and remains, serves to drive a raster scanning path in every television set so that the formation of the video signal into an image and the exact arrangement will remain the same as the original position in the field of raste
camera (picture production), therefore the synchronization signal is always supplied along with the video signal sent anywhere. For the formation of this raster scanning system will require two kinds of synchronization are:

- Namely the horizontal synchronization signal to the horizontal scanning provided at each horizontal retrace.
- Vertical sync signal is for vertical scanning provided on each vertical retrace.

Video signal which is equipped with synchronization signals called the complete video signal (Composite Video signa / CVSl), while for color video signal is called Color Composite Video Signal (CCVS). Because the video signal has been added color information signals, ie signals and signal Burst Color Sub Carrier.


Experimental Procedure:

Circuit Diagram

1. Set-up equipment such as in the picture above.
2. Connect the pattern generator with the power supply 8, 5 V, then turn ON the instrument.

3. Set the TV to Video mode.
4. Pattern generator output switches on and observe put on VIDEO waveforms for each pattern.
4. Observe and take the picture synchronizing signal and horizontal blanking, vertical blanking, front and rear porch, and image information of each pattern.
5. paint and specify voltage waveforms.
6. Pattern generator output switches on and observe put in the IF waveform for each pattern and the measuring frequency.
7. paint of the wave form and specify voltage.
8. Take pictures, the signal for one frame (still image) in composite video, determine the level and periodanya.

Experiment Results

POLA: DOTS

 

PATTERN GENERATOR VIDEO

 

PATTERN GENERATOR IF

POLA: CROSS HATCH

PATTERN GENERATOR VIDEO

PATTERN GENERATOR IF

POLA: VERT LINES

PATTERN GENERATOR VIDEO

PATTERN GENERATOR IF

POLA: HORIZ LINES

PATTERN GENERATOR VIDEO

PATTERN GENERATOR IF

POLA: RASTER

PATTERN GENERATOR VIDEO

PATTERN GENERATOR IF

POLA: COLOR

PATTERN GENERATOR VIDEO

PATERN GENERATOR IF

DATA ANALYSIS:

CALCULATING VOLTAGE:


1. On VIDEO OUTPUT SWITCHES
    Voltage (V) = Amplitude x Volts / DIV

A. DOTS:
V = A x V / div
= 2.97 x 0.1 V
= 0.297 volts / div

B. CROSS Hatch:
V = A x V / div
= 2.9 x 0.1 V
= 0.29 volts / div

C. VERTICAL LINES:
V = A x V / div
= 2.8 x 0.1 V
= 0.28 volts / div

 D. HORIZONTAL LINES:
V = A x V / div
= 2.8 x 0.1 V
= 0.28 volts / div

E. RASTER:
V = A x V / div
= 4.7 x 0.1 V
= 0.47 volts / div

F. COLOUR:
V = A x V / div
= 4.1 x 0.5 V
= 0.41 volts / div



2. On IF OUTPUT SWITCHES
Voltage (V) = Amplitude x Volts / DIV

A. DOTS:
V = A x V / div
= 3.6 x 0.1 V
= 0.36 volts / div

B. CROSS Hatch:
V = A x V / div
= 3.4 x 0.1 V
= 0.34 volts / div

C. VERTICAL LINES:
V = A x V / div
= 3.4 x 0.1 V
= 0.34 volts / div


D. HORIZONTAL LINES:
V = A x V / div
= 3.4 x 0.1 V
= 0.34 volts / div

E. RASTER:
                  V = A x V / div
= 3.4 x 0.1 V
= 0.34 volts / div

F. COLOUR:
V = A x V / div
= 3.8 x 0.1 V
= 0.38 volts / div

IF OUTPUT FREQUENCY COUNTING on
The formula Period = Time / div: waves in 1 period
Frequency = 1: Period
Description: Period (T)
           Frequency (f)
      Waves in 1 period (G)
In view osciloskop assumed 1 box = 1 wave

1. DOTS
T = Time / div: G
= 1 ms: 11 wave
                  = 90 μs
f = 1 / T = 1 / 90 μs
= 11 KHz

2. CROSS Hatch:
T = Time / div: G
= 0.2 ms: 10.5 wave
                  = 19 μs
f = 1 / T = 1 / 19 μs
= 52 KHz

3. VERTICAL LINES:
T = Time / div: G
= 0.2 ms: 10 wave
                  = 20 μs
f = 1 / T = 1 / 20 μs
= 50 KHz

4. HORIZONTAL LINES:
T = Time / div: G
= 0.5 ms: 11 wave
                  = 45 μs
f = 1 / T = 1 / 45 μs
= 22 KHz

5. RASTER :
T = Time / div: G
= 0.2 ms: 11 wave
                  = 18 μs
f = 1 / T = 1 / 18 μs
= 55 KHz

6. COLOUR:
T = Time / div: G
= 0.1 ms: 11 wave
                  = 9μs
f = 1 / T = 1 / 9μs
= 111 KHz

CONCLUSION
1. The video system have a resemble worth one another.
2. At the time of the IF mode is turned down because the amplitude of the voltage will also be down
3. IF output frequency is also almost the same because there is no significant difference in amplitude.
4. The Voltage on the composite video is lower than  any other video system

MODULATOR VIDEO

MODULATOR VIDEO

Objectives:

1. 1. Measuring the frequency spectrum of video transmission.

2. 2. Determine the carrier frequency range image and sound carrier frequency.

3. 3. Specifies the field width (bandwidth) on video transmission.

4. 4. Specify the type of modulation on the picture and sound.

Equipment Used:

1 Modulator video (VCD / VTR / video sender).

1 Spectrum Analyzer.

1 RCA cable connector - BNC.

Circuit diagram:

 

Introduction:

Amplitude modulation or AM as it is often called, is a form of modulation used for radio transmissions for broadcasting and two way radio communication applications. Although one of the earliest used forms of modulation it is still in widespread use today.

The first amplitude modulated signal was transmitted in 1901 by a Canadian engineer named Reginald Fessenden. He took a continuous spark transmission and placed a carbon microphone in the antenna lead. The sound waves impacting on the microphone varied its resistance and in turn this varied the intensity of the transmission. Although very crude, signals were audible over a distance of a few hundred metres, although there was a rasping sound caused by the spark.

With the introduction of continuous sine wave signals, transmissions improved significantly, and AM soon became the standard for voice transmissions. Nowadays, amplitude modulation, AM is used for audio broadcasting on the long medium and short wave bands, and for two way radio communication at VHF for aircraft. However as there now are more efficient and convenient methods of modulating a signal, its use is declining, although it will still be very many years before it is no longer used.

What is amplitude modulation?

In order that a radio signal can carry audio or other information for broadcasting or for two way radio communication, it must be modulated or changed in some way. Although there are a number of ways in which a radio signal may be modulated, one of the easiest, and one of the first methods to be used was to change its amplitude in line with variations of the sound.

The basic concept surrounding what is amplitude modulation, AM, is quite straightforward. The amplitude of the signal is changed in line with the instantaneous intensity of the sound. In this way the radio frequency signal has a representation of the sound wave superimposed in it. In view of the way the basic signal "carries" the sound or modulation, the radio frequency signal is often termed the "carrier".

Amplitude Modulation, AM

When a carrier is modulated in any way, further signals are created that carry the actual modulation information. It is found that when a carrier is amplitude modulated, further signals are generated above and below the main carrier. To see how this happens, take the example of a carrier on a frequency of 1 MHz which is modulated by a steady tone of 1 kHz.

The process of modulating a carrier is exactly the same as mixing two signals together, and as a result both sum and difference frequencies are produced. Therefore when a tone of 1 kHz is mixed with a carrier of 1 MHz, a "sum" frequency is produced at 1 MHz + 1 kHz, and a difference frequency is produced at 1 MHz - 1 kHz, i.e. 1 kHz above and below the carrier.

If the steady state tones are replaced with audio like that encountered with speech of music, these comprise many different frequencies and an audio spectrum with frequencies over a band of frequencies is seen. When modulated onto the carrier, these spectra are seen above and below the carrier.

It can be seen that if the top frequency that is modulated onto the carrier is 6 kHz, then the top spectra will extend to 6 kHz above and below the signal. In other words the bandwidth occupied by the AM signal is twice the maximum frequency of the signal that is used to modulated the carrier, i.e. it is twice the bandwidth of the audio signal to be carried.

How to emit (transmit) signal is amplitude modulated image similar to a radio broadcasting system that has been known. In both cases, the amplitude of a carrier wave radio frequency (RF) is made varies with the modulating voltage. Modulation is a signal of fundamental frequency (baseband). On television, this baseband signal is a composite video signal. Broadcast television is really such a radio system, but includes pictures and sound. Sound signal emitted by joining in it frequency modulation (FM) on a separate carrier wave transmitter in the same channel as the image signal.

Understanding the image signal is used here to mean a modulated carrier wave. The video signal is a signal to a picture tube. Video signal to the television audio signal corresponds to the sound system. Details are clearer than the image signal AM (amplitude modulation picture) and an FM voice signal.

Figure 1 wave amplitude modulated composite video signal.

                            a.                                                     b.

Figure 2. a). Image signal AM frequency spectrum a). Without VSB. b). With VSB

Figure 2.a shows the frequency spectrum of video transmission that produces an image signal comprising AM picture carrier frequency (center frequency) and sound carrier frequencies (frequency side of the upper and lower side frequencies) - without VSB, while Figure 2b shows the frequency spectrum in transmission generate video image signals of AM frequencies only have the upper side only (with VSB).

Experimental Procedure:

1. Calibration Spectrum Analyzer to determine the reference spectrum.
2. Set-up instruments like in the picture above.
3. ON the instrument.
4. Measure the output video modulator (RF) using the Spectrum Analyzer and observe the frequency spectrum.
5. Image of the frequency spectrum.
6. Determine how much an image carrier frequency, carrier frequency sounds, and the difference frequency picture carrier and sound carrier frequency.
7. Observe the spectrum, determine the type of modulation used in transmission, by way of changing the freq. SPAN (skala diperkecil). SPAN (reduced scale).
8. Figure spktrum frequencies multiples of the base frequency. 

Question:

• What system is used in the video modulator?
• From step 6, how to know what types of modulation?

Experimental results: 

	Ref = 105dBμ BW = 300 KHz CF = 206 MHz CP1ΔF - 29,6 MHz 10 MHz / DIV ΔV + 10.8 dB Picture Carrier Frequency: LSB = 206 MHz – 29,6 MHz= 176,4MHz USB = 206 MHz + 29,6 MHz=235,6MHz Voice carrier frequency: can not be seen because of the frequency spectrum analyzer with very small
	Ref = 105dBμ BW = 300 KHz CF = 200 MHz CP1ΔF -10,0 MHz 10 MHz / DIV ΔV + 10.8 dB Picture Carrier Frequency: LSB = 200 MHz –(-6,8MHz)=206,8MHz USB = 200 MHz +(-6,8MHz)=193,2MHz Voice carrier frequency: can not be seen because of the frequency spectrum analyzer with very small.
	Ref = 105dBμ BW = 1 MHz CF = 213 MHz CP1ΔF -148 MHz 50 MHz / DIV ΔV + 10 dB Picture Carrier Frequency: LSB = 213 MHz –(-148 MHz)= 361MHz USB = 213 MHz + (-148 MHz)= 65MHz Voice carrier frequency: can not be seen because of the frequency spectrum analyzer with very small.

 

Data Analysis:

1.    Viewed from the image spectrum that we get can we know that the value of experiment such as::
Carrier frequency: 206 MHz
CP1ΔF - 29,6 MHz
Then:
LSB = 206 MHz – 29,6 MHz= 176,4MHz
USB = 206 MHz + 29,6 MHz= 235,6 MHz

Voice carrier frequency: can not be seen because of the frequency spectrum analyzer with extremely small compared with the frequency carrier

2.    For frequencies multiples:
Frequency of multiples of  picture 1 in: 206 MHz
Frequency of multiples of  picture 2 in: 200 MHz

Frequency of multiples of  picture 3 in: 213 MHz

Answer Question:

1. Modulation system used in the video are amplitude modulation, because the signal amplitude information affect the amplitude of the carrier signal, the signal information into the cover of the carrier signal.                                                                                             Image Signal modulated 
                  A common use of signal Am is: AM radio broadcasting is widely used for broadcast AM radio wave signal, the TV picture (Video), Radio communication: aircraft, amateur radio (SSB), CB radio (Citizens Band Radio). Digital data transmission: Modems Computers (combination with QAM modulation)
   
    Figure of Amplitude Modulation  
   
   
2. Known types of modulation are amplitude modulation can be seen from the changes in amplitude and has a spectrum of AM.
   Based on the equation of the spectrum signal modulated AM. Amplitude modulation will have 3 (three frequencies):
   • Fc : carrier frequency signal
   • LSB: Lower Side Band frequency (LSB), namely the difference frequency carrier signal and the signal information.
   • USB: Upper Side Band frequency (USB) is the number of carrier signal frequency and signal information. 

Conclusion:

1. In a video modulator that is used is amplitude modulation Modulation (AM)
   
2. Amplitudo modulation is shown on a spectrum analyzer displays the three frequencies namely:

Ø  Carrier Frequency

Ø  Frequency of Lower Side Band (LSB), the difference frequency carrier signal and the signal information.

Ø  Frequency of Upper Side Band (USB), the number of carrier signal frequency and signal information.

3. The difference between USB and LSB frequencies are = 59,6 MHz
4.  Bandwidth in used in this experiment is 300 KHz bandwidth

COMPOSITE VIDEO

COMPOSITE VIDEO

PURPOSE:

1.1  Getting to know the basic composite video.

1.2  Measure voltage and standard composite video.

1.3  Determining the parameters of composite video.


EQUIPMENT USED:

1 VCD / VTR
1 Oscilloscope 40 MHz and passive probe
An RCA cable connector - BNC (75W)

Circuit diagram:

 

INTRODUCTION:

The most fundamental job of a video decoder is to separate the color from the black and white information for video composite signals. This task has been achieved many ways since the introduction of color television over 50 years ago. Many different separation methods have been used through the years. With the availability of new cost effective technologies, the consumer has been seeing a gradual improvement in picture quality and detail. Advances in display tube technology and semiconductor processes have pushed the technological envelope providing sharper, more robust video. But separating the chrominance from the luminance information is especially challenging due to the fact that the signals overlap each other in the frequency spectrum. How do you separate them, while minimizing display artifacts?

Composite Signal Construction
The composite video signal is constructed with 3 basic elements:
- Luminance Information from DC to 5.5MHz (B&W Detail)
- Chrominance Information modulated onto a carrier (at 3.58MHz or 4.43MHz)
- Synchronization Information (Horizontal and Vertical Sync)

The three analog elements of a composite video signal carry all the information necessary to display a two dimensional picture on a cathode ray tube (CRT) television.

Luminance (a B&W World)

The luminance signal carries the black and white parts of the picture. This component of the composite video signal requires the most bandwidth (typically to 5MHz), and signal integrity, to convey sharp and clear images. Edge information, brightness, and contrast of the image are entirely contained in the luminance portion of the signal. Until 1947 the broadcast video signal was only black and white. To maintain compatibility with the installed equipment of the time, color or chrominance information was added to the luminance signal

to create the color composite signal as we know it today. Figure 1 shows the specified bandwidths for NTSC and PAL.

Chrominance (an Add-On)The chrominance information is quadrature modulated onto the luminance information. The chrominance is interleaved into the video signal bandwidth between luminance spectra. The chrominance modulation scheme utilizes an I, Q (U, V for PAL) coordinate system where hue and saturation is in vector format. A camera sensor captures light in Red, Green, and Blue (RGB) format. The RGB signal is converted into Y (luminance signal) and I, Q (Color Difference signal) format along with the synchronization information. The I, Q (commonly referred to as C) color information occupies a smaller bandwidth than the Y signal. C bandwidths typically range from 0.6MHz to 1.3MHz. The chrominance signal is modulated onto a carrier. The carrier resides at 3.58MHz for NTSC signals and 4.43MHz for PAL signals. The chroma information must be separated out of the video signal to demodulate it to baseband. This is difficult because luminance information that resides from 2MHz to 5MHz cannot be differentiated from chroma information. Several techniques have been tried over the years to improve separating Y and C, each increasing in complexity and performance.

Don’t Forget the SyncThe synchronization information is also imbedded in the composite video signal and occupies precious amplitude range of the video signal. Horizontal Sync, Vertical Sync (also know as Vertical retrace) and the Color Reference Bursts are embedded in the composite waveform. Figure 2 shows a typical composite signal.

Composite Video Signal Construction

            Composite video signal containing variations of the camera signal (image information), blanking pulses (blanking), and synchronization pulses (sync).

 

Figure 1. Three sets of composite video signal is a variation of the camera signal, blanking pulses, and synchronizing pulses. (A) camera signals (image information) to a single horizontal line, (b) H blanking pulse signal is added to the camera, (c) Toll-alignment of H added to the pulse discharge.

  Figure 2 composite video signals for two horizontal lines

In figure 2, the amplitude of voltage and current are shown sequentially for MRV two horizontal lines in the shadows, as time increases Dalan horizontal direction, the amplitude is changed to white shade, gray, or black in the picture. Starting from the far left at time zero, the signal at the level of white and MRV file located on the left image (the image).

                Once the first line dipayar from left to right, found different cameras with different amplitude signal corresponding to image information is required. After penjejakkan (trace) horizontal camera produces the desired signal for one line, MRV file located on the right image (image or image). Then the discharge pulse is inserted in order to restore the video signal amplitude to the top to the black level, so that repetition of traces can be left empty.

            After emptying time long enough to cover the trail repetition, emptying the voltage is removed. Then & MRV file located on the left, ready to memayar next line. In this way each horizontal line dipayar respectively. Note that the second line shows the dark image information near the black level.

            With regard to time, the amplitude of the signal-amplitude right after emptying in Figure 2 shows the information in accordance with the left side at the start line of MRV. Just before discharge, the signal variation corresponds to the right side. Appropriate information in the middle line of MRV is half the time between discharge pulses.

Figure 3. Details of horizontal blanking and synchronizing pulses.

Details of the horizontal blanking period as figure 3. Intervals marked H is the time required to memayar a complete line including tracking and loop trail.

Pulse-Pulse Alignment in Time Decommissioning V

            Sync pulses are inserted in the composite video signal during vertical blanking pulse width shown in Figure 4. This includes pulses to equalize, pulses vertical alignment and horizontal alignment of multiple pulses. Signal-signal is shown at intervals of time at the end of the field and the next one, to describe what happens during the vertical blanking time. Both signals are shown one above the other are the same, except for half-line shift between successive fields are required for MRV intertwined odd lines.

            Starting from the left in Figure 4, the fourth-last line of MRV horizontal raster shown on the basis of joint discharge pulses and horizontal alignment is needed. Immediately after following the last visible line, the video signal is made into the black by the vertical blanking pulse in preparation for the repetition of vertical trace. Vertical blanking period begins with a group of six pulses MRV, which separate the half-line intervals. Next is the vertical alignment pulse produces real jagged vertical flyback in a series of MRV. Serration also occur at intervals of half a line. Thus, a complete vertical alignment pulse width is three lines. Following the vertical alignment is a another group of six pulse equation and a series of horizontal pulses.During the vertical blanking period as a whole, there is no information on the resulting image, because the signal level is black or blacker than black so that the repetition of vertical traces can be left empty.

Simak

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            In a signal at the summit, the first pulse is a full line of credit beyond the previous horizontal alignment; in signals below for the next field, the first pulse is as far as half a line. The difference this time and a half lines between the even fields and odd continues through all subsequent pulses, so that the pulses of the vertical alignment for successive fields MRV interwoven set time for the odd lines.

Decommissioning & MRV V and V (V Blanking and V Scanning)

            Serrated vertical sync pulses that force the vertical deflection circuit to start the flyback. However, the flyback generally will not begin with the start of vertical alignment because the alignment must build a toll-charge in a capacitor in order to trigger circuits & MRV. If we assume that the vertical flyback starts with the leading edge of the third serration, the elapsed time from one line for vertical alignment before the flyback starts. Also six pulses to equalize the same with the three lines before the vertical alignment. So 3 1 = 4 lines left blank at the bottom of the image, right before the vertical loop trail begins.

            How much time is required for the flyback circuit depends on MRV, but the repetition time of a typical vertical traces are 5 lines. Once the loop trail MRV file from the bottom to the top of raster, produced five complete horizontal lines. Repetition vertical trail can be completed with ease during vertical blanking time. With 4 lines left blank at the base before the flyback and 5 lines emptied during flyback, 12 lines remaining from a total of 21 during during vertical blanking. The 12 blank lines at the top raster in the vertical direction of the surface tracking down. In summary, 4 lines left blank at the bottom and 12 on the top line in each field. In the framework of a total of two fields, 8 lines emptied at the base and 24 lines at the top. MRV lines generated during vertical tracking, but that made black by the vertical blanking, forming black rods at the top and the bottom of the image.
High image is slightly reduced by the discharge, compared with a raster that is not emptied. However, height can be fixed easily by enlarging the amplitude of the sawtooth waveform for vertical & MRV.

EXPERIMENT PROCEDURE:

1.     Set-up equipment as shown above, connect the video out VCR / VCD with CRO input.

2.     ON the instrument.

3.    Set the appropriate CRO to be easily observed (use MODE switch on the TV-H position and / or TV-V, in accordance with the observed images.) When seeing a wave of horizontal synchronization MODE switch put on the TV-H position, while to see a wave of vertical sync put the MODE switch on the TV-V position.

4.    Observe and picture synchronization pulses and horizontal blanking, vertical blanking pulse, the front porch and rear, and image information.

5.   Image of the wave forms and determine the voltage.

QUESTION:
1. What is the frequency of horizontal sync and vertical sync?
2. What system is used in the video? 


EXPERIMENT RESULTS :

1. Without Cassette CD

TV IMAGES V   : 

  1.
                                                                     

  
2. 
 
note : T/D = 2 ms  & V/D = 0,2 V                                                                                   

2 . Cassette CD has not been in play

TV IMAGES V   : 

1.                                                                                                        

                                                                                                                                                                      

 2.

Note : T/D = 2ms & V/D = 0,2V

3. With cassette CD after the play

TV IMAGES V   :

   1. 

2.

   

Note : T/D = 1 ms & V/D = 0,2 V

Data analysis

   ANSWER QUESTIONS:

1. What is the frequency of horizontal sync and vertical sync?
          Frequency = 31.68 KHz horizontal synchronization
          Frequency = 70.71 Hz vertical synchronization
2. What system is used in the video?
          The system used is to use the system pemodulasian AM because it can be seen from the changes in amplitude and has a spectrum of AM.

CONCLUSION:

1. Comprises a composite video signal consisting of variations of image information, pulse blanking (blanking), and pulse alignment (synchronization), each based on a function of time.
2. Interval marked H is the time required to memayar a complete line including tracking and loop trail.
   front porch pulse = 0.02 H
   horizontal sync pulse H = 0.08
   back porch pulse = 0.06 H
   horizontal blanking pulse = 0.16 H