White facsimile transmission
Encyclopedia
In telecommunication
, the term white facsimile transmission has the following meanings:
Both of these terms became outmoded in the late 20th century except in specialist usage, as most fax machines now use the digital ITU-T
fax standards, which encode the image digital
ly over a QAM-modulated signal. See also Black facsimile transmission
.
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
, the term white facsimile transmission has the following meanings:
- In an amplitude-modulatedAmplitude modulationAmplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...
facsimileFaxFax , sometimes called telecopying, is the telephonic transmission of scanned printed material , normally to a telephone number connected to a printer or other output device...
system, transmissionTransmission (telecommunications)Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...
in which the maximum transmitted powerPower (physics)In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
corresponds to the minimum density, i.e., the white area, of the object. - In a frequency-modulated facsimile system, transmission in which the lowest transmitted frequency corresponds to the minimum density i.e., the white area, of the object.
Both of these terms became outmoded in the late 20th century except in specialist usage, as most fax machines now use the digital ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
fax standards, which encode the image digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
ly over a QAM-modulated signal. See also Black facsimile transmission
Black facsimile transmission
In telecommunication, the term black facsimile transmission has the following meanings:# In facsimile systems using amplitude modulation, that form of transmission in which the maximum transmitted power corresponds to the maximum density of the subject....
.