What is System?

Organized, purposeful structure regarded as a 'whole' consisting of interrelated and interdependent elements (components, entities, factors, members, parts etc.). These elements continually influence one another (directly or indirectly) to maintain their activity and the existence of the system, in order to achieve the common purpose the 'goal' of the system. All systems have (a) inputs, outputs, and feedback mechanisms, (b) maintain an internal steady-state (called homeostasis) despite a changing external environment, (c) display properties that are peculiar to the whole (called emergent properties) but are not possessed by any of the individual elements, and (d) have boundaries that are usually defined by the system observer. Systems underlie every phenomenon, and are everywhere one looks for them. They are limited only by the observer’s capacity to comprehend the complexity of the observed entity, item or phenomenon. Every system is a part of a larger system, is composed of sub-systems, and shares common properties with other systems that help in transferring understanding and solutions from one system to another. Systems obey rules which cannot be understood by breaking them into parts, and stop functioning (or malfunction) when an element is removed or altered significantly. Together, they provide a coherent and unified way of viewing and interpreting the universe as a meta-system of interlinked wholes, and of organizing our thoughts about the world. Although different types of systems (from a cell to the human body, soap bubbles to galaxies, ant colonies to nations) look so very different on the surface, they have remarkable similarities. At the most basic level, the systems are divided into two categories: (1) Closed systems: theoretical constructs which have solid boundaries and where only the components within the system are assumed to exist in a self-sufficient state. All other influences or variables from outside the system are considered to be non-existent or insignificant for the purpose of the system analysis. (2) Open systems: the 'real world' systems that have permeable boundaries through which they continually exchange energy, material, and information with their external environment the larger system in which they exist. Different systems methodologies (such as systems dynamics and systems thinking) classify systems differently.

What is Signal?

In electronics, a signal is an electric current or electromagnetic field used to convey data from one place to another. The simplest form of signal is a direct current (DC) that is switched on and off; this is the principle by which the early telegraph worked. More complex signals consist of an alternating-current (AC) or electromagnetic carrier that contains one or more data streams.

Data is superimposed on a carrier current or wave by means of a process called modulation. Signal modulation can be done in either of two main ways: analog and digital. In recent years, digital modulation has been getting more common, while analog modulation methods have been used less and less. There are still plenty of analog signals around, however, and they will probably never become totally extinct.

Except for DC signals such as telegraph and baseband, all signal carriers have a definable frequency or frequencies. Signals also have a property called wavelength, which is inversely proportional to the frequency.

2) In some information technology contexts, a signal is simply "that which is sent or received," thus including both the carrier (see 1) and the data together.

3) In telephony, a signal is special data that is used to set up or control communication.In electronics, a signal is an electric current or electromagnetic field used to convey data from one place to another. The simplest form of signal is a direct current (DC) that is switched on and off; this is the principle by which the early telegraph worked. More complex signals consist of an alternating-current (AC) or electromagnetic carrier that contains one or more data streams.

Data is superimposed on a carrier current or wave by means of a process called modulation. Signal modulation can be done in either of two main ways: analog and digital. In recent years, digital modulation has been getting more common, while analog modulation methods have been used less and less. There are still plenty of analog signals around, however, and they will probably never become totally extinct.

Except for DC signals such as telegraph and baseband, all signal carriers have a definable frequency or frequencies. Signals also have a property called wavelength, which is inversely proportional to the frequency.

2) In some information technology contexts, a signal is simply "that which is sent or received," thus including both the carrier (see 1) and the data together.

3) In telephony, a signal is special data that is used to set up or control communication.In electronics, a signal is an electric current or electromagnetic field used to convey data from one place to another. The simplest form of signal is a direct current (DC) that is switched on and off; this is the principle by which the early telegraph worked. More complex signals consist of an alternating-current (AC) or electromagnetic carrier that contains one or more data streams.

Data is superimposed on a carrier current or wave by means of a process called modulation. Signal modulation can be done in either of two main ways: analog and digital. In recent years, digital modulation has been getting more common, while analog modulation methods have been used less and less. There are still plenty of analog signals around, however, and they will probably never become totally extinct.

Except for DC signals such as telegraph and baseband, all signal carriers have a definable frequency or frequencies. Signals also have a property called wavelength, which is inversely proportional to the frequency.

2) In some information technology contexts, a signal is simply "that which is sent or received," thus including both the carrier (see 1) and the data together.

3) In telephony, a signal is special data that is used to set up or control communication.In electronics, a signal is an electric current or electromagnetic field used to convey data from one place to another. The simplest form of signal is a direct current (DC) that is switched on and off; this is the principle by which the early telegraph worked. More complex signals consist of an alternating-current (AC) or electromagnetic carrier that contains one or more data streams.

Data is superimposed on a carrier current or wave by means of a process called modulation. Signal modulation can be done in either of two main ways: analog and digital. In recent years, digital modulation has been getting more common, while analog modulation methods have been used less and less. There are still plenty of analog signals around, however, and they will probably never become totally extinct.

Except for DC signals such as telegraph and baseband, all signal carriers have a definable frequency or frequencies. Signals also have a property called wavelength, which is inversely proportional to the frequency.

2) In some information technology contexts, a signal is simply "that which is sent or received," thus including both the carrier (see 1) and the data together.

3) In telephony, a signal is special data that is used to set up or control communication.