Monday, 30 November 2020

Baseband

What is Baseband?

Baseband is a signal that has a near-zero frequency range, i.e. a spectral magnitude that is nonzero only for frequencies in the vicinity of the origin (termed f = 0) and negligible elsewhere. In telecommunications and signal processing, baseband signals are transmitted without modulation, that is, without any shift in the range of frequencies of the signal. Baseband has a low-frequency—contained within the bandwidth frequency close to 0 hertz up to a higher cut-off frequency. The baseband can be synonymous with lowpass or non-modulate, and is differentiate from passband, bandpass, carrier-modulate, intermediate frequency, or radiofrequency (RF).


Baseband Signal

Spectrum of a baseband signal, energy “E” per unit frequency as a function of frequency “f”. The total energy is the area under the curve.

Baseband Signal

A base-band signal or lowpass signal is a signal that can include frequencies that are very near zero, by comparison with its highest frequency (for example, a sound waveform can be considered as a basebands signal, whereas a radio signal or any other modulated signal is not).

A base-band bandwidth is equal to the highest frequency of a signal or system, or an upper bound on such frequencies, for example, the upper cut-off frequency of a low-pass filter. By contrast, passband bandwidth is the difference between the highest frequency and a nonzero lowest frequency.

Baseband Channel

A basebands channel or lowpass channel (or system, or network) is a communication channel that can transfer frequencies that are very near zero. Examples are serial cables and local area networks (LANs), as opposed to passband channels such as radio frequency channels and passband filtered wires of the analog telephone network. Frequency division multiplexing (FDM) allows an analog telephone wire to carry a basebands telephone call, concurrently as one or several carrier-modulated telephone calls.

Baseband Processor

A base-band processor is also known as BP or BBP is used to process the down-converted digital signal to retrieve essential data for the wireless digital system. The basebands processing block in GNSS receivers is usually responsible for providing observable data: code pseudo-ranges and carrier phase measurements, as well as navigation data.

Digital Baseband Transmission

Digital base-band transmission, also known as line coding, aims at transferring a digital bit stream over basebands channel, typically an unfiltered wire, contrary to passband transmission, also known as carrier-modulated transmission. Passband transmission makes communication possible over a bandpass filtered channel, such as the telephone network local-loop or a band-limited wireless channel.


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Back-End

What is Back-End?

In the client-server model, the server is usually considered the back end and the client is usually considered the front end, even when some presentation work is actually done on the server itself. The terms front end and back end refer to the separation of concerns between the data access layer (backend), and the presentation layer (front end) of a piece of software, or the physical infrastructure or hardware. The server-side (or "backend") code usually resides on the server, often far removed physically from the user.

In telecommunication, the front can be considered a device or service, while the back is the infrastructure that supports the provision of service. In software architecture, there may be many layers between the hardware and end-user. The front is an abstraction, simplifying the underlying component by providing a user-friendly interface, while the back usually handles data storage and business logic.

Back-end in Software

  • In content management systems, the terms backend may refer to the end-user facing views of the CMS and administrative views, respectively.
  • In speech synthesis, the backend converts the symbolic phonetic representation into actual sounds.
  • For major computer subsystems, the backend launches the programs of the operating system in response.
  • In compilers, the backend works with the intermediate representation to produce code in a computer output language. The backend usually optimizes to produce code that runs faster. The frontend/backend distinction can separate the parser section that deals with source code and the backend that generates code and optimizes. Some designs, such as GCC, offer choices between multiple front ends (parsing different source languages) or back ends (generating code for different target processors).

Back-end in Hardware

  • In processor design, backend design would be the process of mapping that behavior to physical transistors on a die.
Example of Backend as a Web Development Project
  • Scripting languages like PHP, Python, Ruby, Perl, Node.js, or Compiled languages like C#, Java, or Go
  • Automated testing frameworks for the language being used
  • Application Data Access
  • Application Business Logic
  • Database administration
  • Scalability
  • High availability
  • Security concerns, authentication, and authorization
  • Software Architecture
  • Data transformation
  • Backup methods and software

Note: The Backend positions, despite possibly working on one product, have a very distinct set of skills.


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