1. In a facsimile receiver, a device that changes the signal modulation from frequency-shift keying (FSK) to amplitude modulation (AM).
2. In a facsimile transmitter, a device that changes the signal modulation from amplitude modulation (AM) to frequency-shift keying (FSK).

At any point in a frequency-shift facsimile system, the numerical difference between the frequency that corresponds to a white signal and the frequency that corresponds to a black signal.
Note: Facsimile frequency shift is usually expressed in hertz. [From Weik '89]

In facsimile systems, the baseband signal that results from the scanning process.

In a facsimile system, the equipment that converts the facsimile picture signal into a recorded copy.

In a facsimile receiver, the device that performs the final conversion of the facsimile picture signal to an image of the object, i.e., makes the recorded copy.

In a facsimile system, the signal level at any point in the system.
Note 1: The facsimile signal level is used to establish the operating levels.
Note 2: The facsimile signal level is usually expressed in dB with respect to some standard value, such as 1 mW (milliwatt), i.e., 0 dBm.

In a facsimile system, the equipment that sends and receives facsimile signals.
Note: Full-duplex facsimile transceivers can send and receive at the same time; half-duplex facsimile transceivers cannot.

In a facsimile system, the equipment that converts the baseband picture signals, i.e., the baseband signals resulting from scanning the object, into signals suitable for transmission by a communications system.

1. In signal propagation, see fading.
2. In video, the act of dissolving a video picture to either a color, pattern, or titles.
Note: Fading a video image is often used as an artistic tool in video productions, usually seen as a fade to black.
3. In audio, a decrease in the sound level until it is no longer audible.

1. A design allowance that provides for sufficient system gain or sensitivity to accommodate expected fading, for the purpose of ensuring that the required quality of service is maintained.
2. The amount by which a received signal level may be reduced without causing system performance to fall below a specified threshold value. Synonym fading margin.