Different television systems:-
HDTV:High-definition television (HDTV) is digital television broadcasting system with greater resolution than traditional television systems (NTSC, SECAM, PAL). HDTV is digitally broadcast because digital television (DTV) requires less bandwidth if sufficient video compression is used.
The most important aspect of the HDTV, and 1 which gives it its name is the increased the resolution. Standard definition NTSC broadcasts have 525 horizontal lines, and the PAL broadcasts are slightly better at the 625 lines. Both these systems the actual number of lines used to display picture, known as active lines, is lesser than that. In addition, both PAL and NTSC systems are interlaced,i.e each frame is split into 2 fields, 1 field is the odd-numbered lines and the other is even lines. Each frame is displayed alternately and our brain puts them together to create complete image of each frame. This have an adverse affect on picture quality.
Closed-circuit television (CCTV): Closed-circuit television (CCTV) is the use of video cameras to transmit a signal to the specific place, on limited set of monitors. It differs from broadcast television that the signal is not openly transmitted, though it may employ point to point (P2P), point to multipoint, or mesh wireless links.as almost all video cameras fit the definition, term is most often applied to those used in areas that may need monitoring such as the casinos, banks, airports, military installations, and convenience stores. Vidiotelephony is seldom called “CCTV” but those of video in Distance education , where it is the important tool, is often so called In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, example when environment is not suitable for the humans.
CCTV systems can operate continuously or only as required to the monitor the particular event. More advanced form of CCTV, utilizing DVRs, provides recording for possibly many of the years, with a variety of quality and performance options and extra features (such as motion-detection ). More recently, decentralized CCTV cameras based on IP, some equipped with the megapixel sensors, support recording directly to the Network attached the storage devices, or the internal flash for the completely stand-alone operation surveillance of the public using CCTV is particularly common in many of the areas around world including UK, where there are reportedly so many cameras per person than in any other country in world. There and elsewhere, its increasing use has triggered debate about security versus privacy.
Public and private CCTV schemes can be deployed for a number of reasons:
Monitoring public areas to detect incidents and to coordinate police responses. CCTV is also used as an aid for enforcing exclusion orders (where an offender is barred from an area) – see box opposite.
Recording events for use as evidence and to inform investigations. For instance, on the boundaries of the Parliamentary estate, police on patrol alert CCTV operators of incidents via radio links. CCTV operators then record incidents as they unfold.
Directed surveillance of suspected offenders.
Deterrence of criminal activity – although the evidence for this is inconclusive Coaxial cable TV (CATV) systems:
For coaxial (or twisted pair) CCTV lines, use the CCTV/B or ESP CCTV/T. Protectors are available for coaxial RF lines.Transients can also be conducted into CATV systems via the mains power supplies. Many options for mains power protectors are available.
Connect in series with coaxial cable either near where it enters or leaves each building or close to equipment being protected. This should be close to the system’s earth star point (to enable a good connection to earth).
HPCC (High-Performance Computing Cluster), also known as DAS (Data Analytics Supercomputer), is an open source Data intensive computing system platform. The HPCC platform incorporates a software architecture implemented on commodity computing clustures to provide high-performance, data-parallel processing for applications utilizing Big data. The HPCC platform includes system configurations to support both parallel batch data processing (Thor) and high-performance online query applications using indexed data files (Roxie). The HPCC platform also includes a data-centric declarative programming language for parallel data processing called ELC.
Q1: Give the Features & benefits of CATV?
Ans: Features & benefits of CATV:-
- Restricts through let voltage to below the damage levels of interface circuitry.
- Provides repeated protection in lightning intense environments.
- Low attenuation and high return loss over a wide range of frequencies ensures the protectors do not impair system performance.
- Carries AC or DC power.
- Substantial earth termination.
- Supplied ready for flat mounting.
- Strong metal housing.
Q2: What is PAL & SECAM ?
Ans: PAL & SECAM:
While the US, Canada, and Mexico adopted NTSC standards based on a 60 Hz frequency, most other countries developed color television systems based on 50 Hz. (The refresh frequencies varied as they were dependent on the operating frequency of the region’s electrical systems.) Most versions of PAL (Phase Alternating Line) and SECAM (Séquential Colour avec Mémoire) while still employing a 4:3 aspect ratio, had 625 horizontal scan lines. The 100 extra scan lines provided more picture detail, but some felt the slower, 25 Hz scan rate created a noticeable flicker.
Q3: What is MAC and how it works?
Ans: Multiplexed Analogue Components (MAC) was a satellite television transmission standard, originally proposed for use on a Europe-wide terrestrial HDTV system, although it was never used terrestrially.
MAC transmits the luminance and chrominance data separately in time rather than separately in frequency (as other analog television formats do, such as composite vidios ).
Audio and Scrambling (selective access) of MCA:-
- Audio, in format similar to NICAM was transmitted digitally rather than as an FM sub-carrier.
- MAC standard included a standard scrambling systemEuro crypt, a precursor to the standard DVB-CAS encryption system.
Q4: Write the elements to consider when designing any CCTV system?
Ans: Elements to consider when designing any CCTV system:-
- scene, environment
- transmission medium
- Video Signal Management
- Control Equipment.
Q5: What are the approaches to create 3-D content ?
Ans: There are three main approaches to creating 3-D content:
- live camera capture
- computer generated imagery
- 2D to 3D conversion.
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