What is "modulation"

Modulation \Mod`u*la"tion\, n. [L. modulatio: cf. F. modulation.]

1. The act of modulating, or the state of being modulated; as, the modulation of the voice.

2. Sound modulated; melody. [R.]
   --Thomson.

3. (Mus.) A change of key, whether transient, or until the music becomes established in the new key; a shifting of the tonality of a piece, so that the harmonies all center upon a new keynote or tonic; the art of transition out of the original key into one nearly related, and so on, it may be, by successive changes, into a key quite remote. There are also sudden and unprepared modulations.

4. (Electronics) The alteration of hte amplitude, intensity, frequency, or phase (of the carrier wave of a radio signal) at intervals, so as to represent information to be transmitted.

late 14c., "act of singing or making music," from Old French modulation "act of making music" (14c.), or directly from Latin modulationem (nominative modulatio) "rhythmical measure, singing and playing, melody," noun of action from past participle stem of modulari "regulate, measure off properly, measure rhythmically; play, play upon," from modulus (see module). Meaning "act of regulating according to measure or proportion" is from 1530s. Musical sense of "action of process of changing key" is first recorded 1690s.

n. 1 The process of applying a signal to a carrier, modulate. 2 The variation and regulation of a population, physiological response, etc.

1. n. a musical passage moving from one key to another [syn: transition]

2. (electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase

3. rise and fall of the voice pitch [syn: intonation, pitch contour]

4. a manner of speaking in which the loudness or pitch or tone of the voice is modified [syn: inflection]

5. the act of modifying or adjusting according to due measure and proportion (as with regard to artistic effect)

In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.

In telecommunications, modulation is the process of conveying a message signal, for example a digital bit stream or an analog audio signal, inside another signal that can be physically transmitted. Modulation of a sine waveform transforms a baseband message signal into a passband signal.

A modulator is a device that performs modulation. A demodulator (sometimes detector or demod) is a device that performs demodulation, the inverse of modulation. A modem (from modulator–demodulator) can perform both operations.

The aim of analog modulation is to transfer an analog baseband (or lowpass) signal, for example an audio signal or TV signal, over an analog bandpass channel at a different frequency, for example over a limited radio frequency band or a cable TV network channel.

The aim of digital modulation is to transfer a digital bit stream over an analog bandpass channel, for example over the public switched telephone network (where a bandpass filter limits the frequency range to 300–3400 Hz) or over a limited radio frequency band.

Analog and digital modulation facilitate frequency division multiplexing (FDM), where several low pass information signals are transferred simultaneously over the same shared physical medium, using separate passband channels (several different carrier frequencies).

The aim of digital baseband modulation methods, also known as line coding, is to transfer a digital bit stream over a baseband channel, typically a non-filtered copper wire such as a serial bus or a wired local area network.

The aim of pulse modulation methods is to transfer a narrowband analog signal, for example a phone call over a wideband baseband channel or, in some of the schemes, as a bit stream over another digital transmission system.

In music synthesizers, modulation may be used to synthesise waveforms with an extensive overtone spectrum using a small number of oscillators. In this case the carrier frequency is typically in the same order or much lower than the modulating waveform (see frequency modulation synthesis or ring modulation synthesis).

In music, modulation is most commonly the act or process of changing from one key ( tonic, or tonal center) to another. This may or may not be accompanied by a change in key signature. Modulations articulate or create the structure or form of many pieces, as well as add interest. Treatment of a chord as the tonic for less than a phrase is considered tonicization.

Modulation is the process of varying one or more properties of a high-frequency periodic waveform.

Modulation, Modulations, Modulate and Modulator may also refer to:

As part of its Agenda 2000 reforms, and effective 1 January 2000, EU member-countries may reduce (or modulate) direct aid to producers (by a maximum of 20%) in cases where:

• the labour employed in a farm falls below a threshold set by national authorities;
• the overall prosperity of the holding is above a certain limit;
• and, the total payments granted under support programs exceed a limit set by national authorities.

The savings that result and those from cross-compliance or econ-conditionality (observance of environmental criteria) may be used by the member countries to supplement EU funding for early retirement measures, payments for less favoured areas and areas subject to environmental restrictions, agri-environmental provisions, afforestation and rural development.

Modulation is an essential element of the EU Commission’s Mid-term Review (MTR) proposals. Funds acquired from the reduction of payments to farms will be allocated to rural development under the MTR.