Interview Questions.

Question 1. What Are The Basic Factors With Which The Tv System Must Deal For Successful Transmission And Reception Of Picture?

Answer :

Gross shape
Image continuity
No of scanning lines
Flicker
Fine structure
Total degradation
Question 2. What Is Vertical Scanning?

Answer :

It is the motion of electron beam spot inside the vertical route.

Question 3. What Is Raster?

Answer :

Raster is the experiment pattern in which an area is scanned from aspect strains from top to backside.

Question 4. What Is Scanning?

Answer :

Scanning is the process by way of which an electron beam spots a mode to move across a rectangular region with the intention to cowl it absolutely.

Question five. What Is Horizontal Scanning?

Answer :

The movement of electron beam spot from left to proper and returned if you want to begin a brand new line in same path is termed as horizontal scanning.

Question 6. What Is Video Signal?

Answer :

The time various electrical signal voltage obtained from the TV camera tube circuit representing the unique distribution of brightness of the image is called video sign.

Question 7. What Are The Uses Of Radar?

Answer :

Detection and Search Radar: Radar is basically utilized in detection cause in navy and coastal surveillance which assist the humans in detecting the harmful objects coming toward them.

Missile steerage gadget: Nowadays, this radar has turn out to be quite popular in missile steering because it helps the humans in knowing in which to release the missile or in which to land it and so on.

Air Traffic manipulate: In overseas international locations, the traffic is being controlled through the usage of radar.

Weather Forecasting: This is quiet useful in weather forecasting because it facilitates in detecting the temperature of climate or when will the rainfall happens.

Question 8. What Is Doppler Effect?

Answer :

The sudden change in pitch of a car horn as a car passes through (source movement) or inside the pitch of a boom container at the sidewalk as you pressure by way of in your car (observer motion) was first explained in 1842 through Christian Doppler. His Doppler Effect is the shift in frequency and wavelength of waves which results from a supply moving with respect to the medium, a receiver moving with recognize to the medium, or maybe a transferring medium.

Although first found for sound waves, the Doppler impact holds authentic for all forms of waves along with mild (and different electromagnetic waves). The Doppler Effect for light waves is generally described in phrases of colours rather than frequency. A purple shift happens when the source and observer are transferring far from every other, and a blue shift happens whilst the source and observer are transferring in the direction of each different. The purple shift of mild from remote galaxies is evidence that the universe is increasing.

Question nine. What Are The Factors That Affect Radar Performance?

Answer :

The overall performance of a radar system may be judged by means of the following:

The most range at which it can see a target of a distinct length.
The accuracy of its measurement of target area in range and attitude.
Its ability to distinguish one goal from another.
Its capacity to stumble on the preferred goal echo whilst masked with the aid of massive clutter echoes, accidental interfering signals from different “pleasant” transmitters, or intentional radiation from antagonistic jamming (if a navy radar).
Its capability to understand the form of goal.
Its availability reliability, and maintainability.
Question 10. Why Flicker Is Not Removed By Progressive Scanning?

Answer :

Flicker can be removed by using doubling the velocity of modern scanning, however doubling the rate will double the band-width, which is not appropriate.

Question eleven. Why Is Retrace Blanked?

Answer :

Retrace his blanked due to the retrace is visible on the screen, it will cause distortion in the image.

Question 12. What Is Kell Factor (ok)?

Answer :

The kell factor (ok) or the decision issue offers the powerful number of horizontal scanning strains may be scanned due to sensible quandary. The value of kell issue lies between zero.65 to zero.75.

Question 13. What Is Importance Of Back Porch?

Answer :

Back porch absorbs ringing oscillations due to fly-again. In the absence of the returned porch, those oscillations might have distorted the video sign.

Question 14. Which Principles Are Used For Optical Electrical Conversion?

Answer :

Two fundamental concepts are used for optical electric conversion. They are based on photo electric effect.

The two principles are: 

Photoemission.
Photo conduction.
Question 15. List four Merits Of Digital Tv Receivers?

Answer :

Reduced ghosts. Reduced of 50 HZ flicker. High decision snap shots. Slow motion motion.

Question sixteen. Write Short Notes On Video Disc System?

Answer :

The video disc is crucial a gramophone report with photographs on it. The first video disc became the laser optical and 2nd video disc gadget is based on the capacitance precept.

Question 17. Why Do Blind Speeds Occur?

Answer :

Blind speeds arise due to the samples nature of the heart beat radar wave shape. Thus it's far sampling that is the reason of ambiguities or aliasing in the measurement of the Doppler frequency.

Question 18. What Do You Mean By Longitudinal Video Recording?

Answer :

A method wherein video indicators are recorded on at the least several tracks alongside the length of the tape.

Question 19. What Are The Two Types Of Video Disc System?

Answer :

Laser or optical disc gadget. Capacitance disc machine.

Question 20. What Is The Function Of Tv Camera Tube? What Are The Major Problem Occurring During The Conversion Of Optical To Electrical Signal In Tv Camera?

Answer :

Heart of a TV digicam is a digital camera tube.
Camera tube –converts optical facts into electric sign.
Amplitude proportional to brightness.
Optical photo is targeted by a lens assembly to a rectangular glass face –plate.
Transparent conductive coating at the inner side of the glass faces plate.
On that's laid a skinny layer of picture conductive material having a completely excessive resistance when no light falls on it.
Resistance decreases whilst the depth will increase.
Electron beam –used to pick up the picture records available on the target plate in phrases of varying resistance.
Beam is fashioned by an electron gun:

Deflection coils are fed separately from  oscillators-constantly generates saw enamel wave paperwork having one of a kind favored frequency makes use of magnetic deflection.
Deflection by first coil-horizontal movement of beams and then brings speedy to left facet to start the hint of subsequent line.
Deflection by 2d coil-Vertical movement and its short retrace again to the pinnacle to start the process allover once more.
Encounters different resistance throughout the target plate.
Result in a waft of cutting-edge which varies in magnitude during scanning.
We get the true information of the scene:

Scanning converts the in antenna formation current in area and time coordinates into time variant best –known as a video signal.
Video signal is amplified-amplitude modulated with channel photo service frequency.
The important problems at some stage in this conversion are:

Poor sensitivity.
Poor resolution.
Higher noise degree.
Improper spectral reaction.
Instability.
Poor evaluation range.
Difficulties in processing the output signal.
Question 21. Explain How The Image Orthicon Develops Video Signal When Light From Any Scene Is Focused On Its Face Plate?

Answer :

It was first produced within the yr 1945 and because of its superior overall performance it’s soon replaced all earlier tv digital camera tube like image dissector, iconoscope   and orthicon. 

It has the following traits: 

It has excessive image picture sensitivity. 
It provides a very reliable service. 
It provides an splendid reaction over a wide. 
Range of illumination degree various from brilliant sunlight to dark shadow. As a end result of this, picture orthicon remained in famous TV studio use for a long period however it's miles now being changed via plumb icon.

Principle of working:

A lens system focuses light from the scene on to a translucent picture cathode.
Electrons gate emitted from the numerous factors on photocathode surface in proportion to the illumination .
These picture electrons travel to a skinny glass target inflicting secondary emission from it.
These secondary electrons get gathered through a quality mesh positioned close to the glass target plate as shown fig.
This reasons electron deficiency distribution or superb charge distribution at the photo cathode.
This high quality charge distribution at the beginning on the the front floor of the target plate leaks via skinny plate to the back floor.
A low pace scanning beam from an electron at the opposite stop of the photograph orthicon tube scans the returned surface of the target plate following a predetermined scanning sample.
The electroned is bogged down to a non zero pace because it strategies the goal.
From a darkish detail ,the scanning electron beam is back  unaffected .However ,at mild element(positively  rate element),the scanning beam is disadvantaged of some of its electrons to netralise the advantageous charge so that the returning electrons to neutralize the high-quality rate so that the returning electron beam carries lesser electron .This various density  returning beam  is fed to an electron multiplier.

Question 22. What Is The Principle Of Operation Of Guided Wave Radar?

Answer :

Radar level dimension generation may be broken down into  unique classes; Pulsed and Frequency Modulated Continuous Wave (FMCW).
An benefit with Pulsed Technology is that it calls for less processing electricity. Therefore most -twine gauges use this era.
An advantage with FMCW is that better accuracy may be done however more processing strength is needed and therefore FMCW-radars are usually 4-twine.
In Pulsed transmitters the extent dimension is a characteristic of the time taken from the radar signal to tour to the floor and back.
In FMCW gauges the transmitter constantly emits a swept frequency and the space is calculated by means of the difference in frequency of emitted and acquired sign.
Question 23. Are Radar Gauges Safe?

Answer :

Yes. The emitted sign is much less than 3 percent of most leakage allowed from a microwave oven. Radar waves are of no greater intensity than the constant radio, cellular and different verbal exchange waves that surround us each day.

Furthermore the transmitter is usually located in a metal tank that acts as a Faraday’s cage and therefore the radar waves are isolated inside the tank.

Question 24. What Is The Difference In Frequency Between Pulsed Technology Guided Wave Radar And Non Contacting Radar?

Answer :

With Guided Wave Radar the pulsed microwave are guided down the tank through the probe, making it much less touchy to disturbances than free propagating microwaves.

Pulsed Non Contacting Radar makes use of a provider frequency, e.G. 6 Hz or 26 Hz, to carry the microwaves which might be radiated into the tank with an antenna.

Question 25. Why Should We Use Radar Technology?

Answer :

The radar signal is actually unaffected via the tank content and tank ecosystem, temperature or pressure. The dimension isn't motivated by way of changing fabric characteristics inclusive of density, dielectric houses and viscosity.

Since there are not any transferring parts the transmitters are certainly renovation unfastened. All of the traits above make radar a completely useful and rapid growing level measurement generation.

Question 26. How Does The Frequency Of The Radar Affect The Measurement?

Answer :

A higher frequency presents a extra focused slim beam which can be beneficial in packages where there are obstacles gift inside the tank consisting of many-approaches, agitators or heating coils.

The disadvantage of high frequency is that the dimension is extra tormented by vapers, dirt and product building up at the antenna, Low frequency radar which has an extended wavelength and wider beam perspective, has a tendency to manage better with steam, dirt, condensation, contamination and turbulent surfaces.

Question 27. In What Way Does The Dielectric Constant (dc) Of The Media Affect The Measurement?

Answer :

Electromagnetic energy is emitted from all radar gadgets. When the emitted signal reaches a point wherein there is a change in DC, typically the media floor, a number of the signal is contemplated returned to the transmitter.
The amount of energy that is meditated lower back to the transmitter is proportional to the DC of the media. A rule-of-thumb is that the fee of the dielectric regular represents the share of power that is contemplated.
Thus a DC of eight means that eight percentage of the emitted energy is pondered lower back to the transmitter. Fundamentally media with a higher DC offer stronger return alerts and are therefore easier to degree.
Question 28. Does Radar Work On Foam?

Answer :

The outcomes of froth on a radar dimension can be difficult to are expecting. In some applications the froth may additionally hose down out the signal absolutely while different varieties of foam can be obvious to the transmitter.
The thickness, density and the dielectric regular are factors that need to be considered while evaluating an utility with foam.
On dry foam the microwaves usually passes through and detects the liquid surface underneath. On medium type foam the signal may be absorbed or scattered and the effects are consequently hard to expect.
If the foam is moist the microwaves are often reflected from the froth floor and thereby the froth surface level is measured.
The frequency at which the radar operates also influences how foam is measured. Low frequency radar (5 GHz) in fashionable penetrates foam to a larger quantity than high frequency (20 GHz) radar.
Guided Wave Radar is in wellknown better proper to degree on packages in which foam is gift, for the reason that radar uses a decrease frequency pulse.
Question 29. Are There Any Restrictions On What Still-pipe Material Can Be Used?

Answer :

Any form of conductive fabric can be used as long as it's far well matched with the procedure media.

If the fabric is not conductive it is going to be obvious to the radar-beams and consequently it'll haven't any effect.

Question 30. Will Two Or More Radar Units In One Vessel Conflict With Each Other?

Answer :

The signals from  or greater transmitters in a single tank will now not blend and therefore the radar gadgets will now not warfare with every different.

If it worries two or greater 3300s the policies for close by items might follow to the probes as they do to other metal gadgets close by. For that purpose the probes need to be installed a sure distance away from each different.

Question 31. Will Radio Noise Or Other Interference Cause Problems?

Answer :

The transmitters use a particular slim frequency and are therefore no longer liable to disturbances from different assets.

It is very unusual with disturbances and it's far uncommon that the disturbance supply operates at precisely the identical frequency because the transmitter.

Furthermore, the transmitters are frequently mounted in metal tanks that provide a Faraday’s cage which prevents electromagnetic disturbances from the outside to enter the tank. With Guided Wave Radar, if disturbances are present in tank the coaxial probe are endorsed, because the radar signal travels interior of the pipe undisturbed by the interference resources on the outdoor.

Question 32. Are There Any Restrictions On The Nozzle Height?

Answer :

Since the nozzle, and mainly the decrease stop of the nozzle, can create interfering echoes it's far endorsed that the peak of the nozzle is kept within certain values depending on the kind of probe / antenna and form of transmitter that is used.

Question 33. Are There Any Restrictions On The Nozzle Diameter?

Answer :

In conjunction with the above announcement, the nozzle diameter additionally influences the size.

Since a diameter nozzle this is too small will create disturbance echoes.

Question 34. Are There Any Restrictions When Measuring In Stilling Pipes?

Answer :

Pipes ought to be an all-metallic fabric. Non-metal pipes or sections aren't recommended for non-contacting radar.

Plastic, Plexiglas, or other non-metal substances do now not protect the radar from outside disturbances and provide minimal, if any, utility gain.

Other requirements include:

Pipe have to have a regular internal diameter
Pipe must be smooth at the interior (smooth pipe joints are suited, however might also lessen accuracy)
Avoid deposits, rust, gaps and slots
One hole above the product surface
Minimum entire diameter is 0.25 in. (6 mm)
Whole diameter (Ø) have to not exceed 10% of the pipe diameter (D)
Minimum distance among holes is 6 in. (a hundred and fifty mm) (1)
Holes have to be drilled on one side and de-burred
Ball valve or different full valves should be completely open
Failure to comply with those requirements may additionally have an effect on the reliability of the extent size.

Question 35. What Is Purpose Of Exotic Materials?

Answer :

In some programs with excessive temperatures, or in pretty corrosive surroundings, the probes or antennas want to be made from distinguished substances that can be stand the cloth stress.

Two exclusive distinct materials as standards: Alloy four hundred C-276

Question 36. What Is Eddl & Dd’s? And How Do They Affect Configuration Tools And Host Systems?

Answer :

Basic configuration can without problems be finished both with Rosemount Radar Master, a Rosemount 375 Field Communicator, the AMS™ Suite, DeltaV® or any other DD (Device Description) like minded host machine.
For advanced configuration capabilities and great diagnostics, Radar Master, or an alternative host that supports superior EDDL (which include the AMS Device Manager) is needed.
Rosemount Radar Master is distributed with each transmitter however it's also feasible to download Radar Master or other DD’s on Rosemount.Com Radar Master is a person-pleasant, Windows primarily based software program bundle that offers clean configuration and carrier for both FOUDATION™ fieldbus and HART®.
A wizard courses the person to enter the specified parameters for a fundamental configuration. “Measure & examine” functionality is accessed through Radar grasp. It allows automated inspiration of stage threshold values, thereby making hard packages clean to configure.
Radar Master also consists of an echo curve with movie feature, off-line configuration, logging and enormous on line help. The Enhanced EDDL abilties of the Rosemount Radars additionally make it viable to view the echo curve from a discipline communicator or AMS, and to provoke the Measure-and-Learn functionality inside the transmitter.
Question 37. How Will Coating Affect The Measurement?

Answer :

If coating bureaucracy on the probe the measured signal may be weaker. If the media itself has a excessive dielectric consistent a few coating isn't always much situation but if it's miles a low DC media coating can be a problem.

If a dual probe or a coaxial probe is used the coating can reason bridging between the two leads and this may create fake echoes that can lead the transmitter to interpret a bridge as the actual degree.

Single lead is usually recommended in coating applications. Coating can motive an accuracy impact. Maximum error because of coating is 1-10% relying on probe type, dielectric regular, coating thickness and coating top above product surface.

Question 38. What Are The Special Considerations For Interface Measurement?

Answer :

For interface measurement a few standards must be fulfilled:

The dielectric of the higher product have to be recognised and need to now not vary.
Upper product dielectric < Lower product dielectric.
Difference between dielectrics depends on the upper product thickness, but a guideline is > 10(3300) > 6(5300).
Thickness of upper product > 10 cm (four in.) for coax, inflexible twin and rigid unmarried probes and 20 cm (eight in) for flexible twin probes with the intention to be detected.
The max measuring variety is constrained with the aid of the top product dielectric consistent.
Coaxial, Twin probes or inflexible unmarried may be used.
Max upper product DC is 5 for dual lead probes and 10 for coaxial probe.
Target packages consist of interfaces between oil/oil-like (DC < 3) and water/water-like liquids (DC > 20). Consult manufacturing unit concerning different interface applications and while emulsion layer!

Question 39. Can Guided Wave Radar Measure Emulsion Layers?

Answer :

Emulsion layers are in trendy hard to are expecting and there are three primary varieties of layers:

DC of pinnacle layer and emulsion layer is comparable (difference in dielectric steady < 10). In this case the interface level as reported by the transmitter will be the bottom of the emulsion layer.
DC of bottom layer and emulsion layer is similar (difference in dielectric constant between top layer and emulsion layer > 10). In this situation the interface level as suggested by way of the transmitter may be the top of the emulsion layer.
There is a linear transition in DC from the lowest to the top of the emulsion layer. In this situation it's miles hard to predict where the mentioned interface level is. If the linear transition is over an extended distance there is a hazard that no interface echo is contemplated returned to the transmitter.
Since the reflecting pulse is created when there may be a wonderful change in DC. If a linear oil water interface is very skinny (< 10 cm) the transmitter might likely deliver a terrific signal from the interface because the emulsion is so thin and the difference in dielectrics between oil and water is massive.
It is difficult to mention though where the transmitter will document the interface stage. It can report the pinnacle of, the bottom of, or someplace inside, the emulsion layer.
Question 40. Will The Guided Wave Radar See Sand In The Bottom Of A Vessel?

Answer :

No. Since the sand could be embedded in water that's a high dielectric media (DC~80) the transmitter will most effective see the water.

The identical is true for all media which might be embedded in water.

Question 41. Is There Any Inactive Part Of The Probe?

Answer :

The energetic measuring range is decreased through the higher and decrease dead zones. The top lifeless area is the minimal distance from the reference factor to the product surface.

The measuring variety is likewise reduced in the end of the probe by way of the decrease useless quarter.

How massive the top and lower dead zones are depend upon probe kind and the dielectric consistent of the measured media.

Question forty two. How Close To The Tank Wall Can The Probe Is Mounted?

Answer :

Like the nozzle the tank wall can also affect the dimension via disturbance echoes.

The minimal distance to the tank wall is similar to the gap to any stressful item that can be present in the tank.

If there are barriers present in the tank the coaxial probe is the nice probe to use. If the tank wall is metallic and smooth the probe can be hooked up toward the wall.

Question 43. What Pull Force Will Break A Flexible Single Lead Probe?

Answer :

In solid application, media may cause down-pull forces on silo roofs. The silo roof must be able to resist the probe collapse load or at the least the maximum probe tensile load.
The tensile load relies upon at the silo size, fabric density, and the friction coefficient. Forces boom with the buried period, the silo and probe diameter.
In critical instances, such as for merchandise with a chance for build-up, it's miles better to use a 0.24 in (6 mm) probe.
Depending on their position, forces on probes are typically two or ten instances extra on probes with tie-down than on probes with ballast weights.
Question 44. What Is The Principle Of Operation For Non Contacting Radar?

Answer :

FMCW technology transmitter constantly emits a swept frequency signal and the space is calculated with the aid of the difference in frequency among the emitted and obtained sign at any factor in time.
One gain with FMCW is that higher accuracy can be accomplished.
The Pulsed Radar transmitter is loose propagating radar. The level of the liquid is measured with the aid of brief radar pulses which can be transmitted from the antenna at the tank top closer to the liquid.
When a radar pulse reaches a media with a unique dielectric regular, part of the power is pondered returned to the transmitter.
The time distinction among the transmitted and the reflected pulse is proportional to the gap, from which the extent is calculated.
Question forty five. How Close To The Tank Wall Can The Non Contacting Transmitter Is Mounted?

Answer :

The minimum distance to the tank wall depends on which antenna is used. With a greater focused beam (larger antenna), the closer to the tank wall the tool can be established.

Question forty six. What Are The Special Considerations When Measuring Ammonia?

Answer :

Tanks with anhydrous ammonia have a heavy vapor above the floor that attenuates the signal from the radar transmitter. A higher strain in the tank will reason a extra attenuated sign.

A unique method is consequently used to evaluate what the most measuring range is in anhydrous ammonia as a feature of the strain in the tank.

For the 5600 the method is:

Max Measuring Range (m) = 20 / Pressure in Bar

Note that, whilst measuring anhydrous (aqueous) ammonia, this components does now not follow. Hydrous ammonia has a high dielectric steady and therefore affords proper reflection.

Question forty seven. Why Do You Use Process Seal Antennas?

Answer :

To isolate electronics from manner in tank along with vapour and corrosion. The Process Seal antenna has a PTFE window. It is an all PTFE antenna (all substances exposed to tank environment are PTFE).

Due to the smooth surface of the window and the non-sticky nature of PTFE it could be used on some hygienic programs.