Analog television

Analog television or analogue television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by rapid variations of either the amplitude, frequency or phase of the signal.

Analog signals vary over a continuous range of possible values which means that electronic noise and interference becomes reproduced by the receiver. So with analog, a moderately weak signal becomes snowy and subject to interference. In contrast, a moderately weak digital signal and a very strong digital signal transmit equal picture quality. Analog television may be wireless or can be distributed over a cable network using cable converters.

All broadcast television systems preceding digital transmission of digital television (DTV) used analog signals.

Analog television around the world has been in the process of shutting down since the late 2000s.

Development

The earliest systems were mechanical television systems which used spinning disks with patterns of holes punched into the disc to scan an image. A similar disk reconstructed the image at the receiver. Synchronization of the receiver disc rotation was handled through sync pulses broadcast with the image information. However these mechanical systems were slow, the images were dim and flickered severely, and the image resolution very low. Camera systems used similar spinning discs and required intensely bright illumination of the subject for the light detector to work.

Randomness

Randomness is the lack of pattern or predictability in events. A random sequence of events, symbols or steps has no order and does not follow an intelligible pattern or combination. Individual random events are by definition unpredictable, but in many cases the frequency of different outcomes over a large number of events (or "trials") is predictable. For example, when throwing two dice, the outcome of any particular roll is unpredictable, but a sum of 7 will occur twice as often as 4. In this view, randomness is a measure of uncertainty of an outcome, rather than haphazardness, and applies to concepts of chance, probability, and information entropy.

The fields of mathematics, probability, and statistics use formal definitions of randomness. In statistics, a random variable is an assignment of a numerical value to each possible outcome of an event space. This association facilitates the identification and the calculation of probabilities of the events. Random variables can appear in random sequences. A random process is a sequence of random variables whose outcomes do not follow a deterministic pattern, but follow an evolution described by probability distributions. These and other constructs are extremely useful in probability theory and the various applications of randomness.

Human back

The human back is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck and the shoulders. It is the surface opposite to the chest, its height being defined by the vertebral column (commonly referred to as the spine or backbone) and its breadth being supported by the ribcage and shoulders. The spinal canal runs through the spine and provides nerves to the rest of the body.

Structure

The central feature of the human back is the vertebral column, specifically the length from the top of the thoracic vertebrae to the bottom of the lumbar vertebrae, which houses the spinal cord in its spinal canal, and which generally has some curvature that gives shape to the back. The ribcage extends from the spine at the top of the back (with the top of the ribcage corresponding to the T1 vertebra), more than halfway down the length of the back, leaving an area with less protection between the bottom of the ribcage and the hips. The width of the back at the top is defined by the scapula, the broad, flat bones of the shoulders.

Disk formatting

Disk formatting is the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk or USB flash drive for initial use. In some cases, the formatting operation may also create one or more new file systems. The first part of the formatting process that performs basic medium preparation is often referred to as "low-level formatting".Partitioning is the common term for the second part of the process, making the data storage device visible to an operating system. The third part of the process, usually termed "high-level formatting" most often refers to the process of generating a new file system. In some operating systems all or parts of these three processes can be combined or repeated at different levels and the term "format" is understood to mean an operation in which a new disk medium is fully prepared to store files.

As a general rule, formatting a disk leaves most if not all existing data on the disk medium; some or most of which might be recoverable with special tools. Special tools can remove user data by a single overwrite of all files and free space.

Porch

A porch (from Old French porche, from Latin porticus "colonnade", from porta "passage") is a construction usually external to the walls of the main building proper, but may be enclosed by latticework, broad windows, screen, or other light frame walls extending from the main structure.

There are various styles of porches, all of which depend on the architectural tradition of its location. All porches will allow for sufficient space for a person to comfortably pause before entering or after exiting the building. However, they may be larger. Verandahs, for example, are usually quite large and may encompass the entire facade as well as the sides of a structure. An extreme example is the Grand Hotel on Mackinac Island, Michigan, which has the longest porch in the world at 660 feet (200 m) in length.

North America

In northeastern North America, a porch is a small area, usually unenclosed, at the main-floor height and used as a sitting area or for the removal of working clothes so as not to get the home's interior dirty, when the entrance door is accessed via the porch. In the Southwestern United States, ranch-style homes often use a covered porch to provide shade for the entrance and southern wall of the residence.