Originally Gaussian frequency-shift keying ( GFSK ) modulation was the only modulation scheme available ; subsequently, since the introduction of Bluetooth 2. 0 + EDR, π / 4-DQPSK and 8DPSK modulation may also be used between compatible devices.

EDGE, like GPRS, uses a rate adaptation algorithm that adapts the modulation and coding scheme ( MCS ) according to the quality of the radio channel, and thus the bit rate and robustness of data transmission.

* Frequency-shift keying, an electronic communications modulation scheme

The bit stream is split into several parallel data streams, each transferred over its own sub-carrier using some conventional digital modulation scheme.

OFDM is essentially identical to coded OFDM ( COFDM ) and discrete multi-tone modulation ( DMT ), and is a frequency-division multiplexing ( FDM ) scheme used as a digital multi-carrier modulation method.

Quadrature amplitude modulation ( QAM ) is both an analog and a digital modulation scheme.

It conveys two analog message signals, or two digital bit streams, by changing ( modulating ) the amplitudes of two carrier waves, using the amplitude-shift keying ( ASK ) digital modulation scheme or amplitude modulation ( AM ) analog modulation scheme.

QAM is used extensively as a modulation scheme for digital telecommunication systems.

Throughput over analog channels is defined entirely by the modulation scheme, the signal to noise ratio, and the available bandwidth.

Passband digital transmission requires a digital modulation scheme, often provided by modem equipment.

In the 10PASS-TS case the VDSL standard is utilized, which is based on the Discrete multi-tone modulation ( DMT ) scheme.

The BER may be improved by choosing a strong signal strength ( unless this causes cross-talk and more bit errors ), by choosing a slow and robust modulation scheme or line coding scheme, and by applying channel coding schemes such as redundant forward error correction codes.

Signal processors, such as four-phase modems, cannot change the DSR, but the modulation rate depends on the line modulation scheme, in accordance with Note 4.

Eye diagram showing an example of two power levels in an On-off keying | OOK modulation scheme which can be used to calculate extinction ratio.

Corrections were applied for modulation broadening, apparatus background, and field shift.

Amplitude modulation ( AM ) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave.

This noise can be avoided by modulation of the signal at a higher frequency, for example through the use of a lock-in amplifier.

Field modulation of a very high speed AC generator was also used for some early AM radio transmissions .< ref >

Topiramate, is another treatment option for resistant catatonia ; it produces its therapeutic effects by producing glutamate antagonism via modulation of AMPA receptors.

In 1975, the Japanese company Yamaha licensed the algorithms for frequency modulation synthesis ( FM synthesis ) from John Chowning, who had experimented with it at Stanford University since 1971.

Yamaha's engineers began adapting Chowning's algorithm for use in a commercial digital synthesizer, adding improvements such as the " key scaling " method to avoid the introduction of distortion that normally occurred in analog systems during frequency modulation, though it would take several years before Yamaha release their FM digital synthesizers.

With some implementations, image resolution may be less directly limited by bandwidth ; for example in DVB-T, broadcasters can choose from several different modulation schemes, giving them the option to reduce the transmission bitrate and make reception easier for more distant or mobile viewers.

For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications.

Transmissions across free space require information to be encoded in a carrier wave to shift the information to a carrier frequency suitable for transmission, this is known as modulation.

These amplifiers use pulse width modulation, pulse density modulation ( sometimes referred to as pulse frequency modulation ) or a more advanced form of modulation such as Delta-sigma modulation ( for example, in the Analog Devices AD1990 class-D audio power amplifier ).

In addition to Gaussian minimum-shift keying ( GMSK ), EDGE uses higher-order PSK / 8 phase shift keying ( 8PSK ) for the upper five of its nine modulation and coding schemes.

He received in 1942 the AIEEs Edison Medal " for distinguished contributions to the art of electric communication, notably the regenerative circuit, the superheterodyne, and frequency modulation ".

It is essential for proper adaptation to stress and specific modulation of emotional learning and memory.

The harmonic distribution of a sine wave carrier modulated by such a sinusoidal signal can be represented with Bessel functions ; this provides the basis for a mathematical understanding of frequency modulation in the frequency domain.

The carrier and sideband amplitudes are illustrated for different modulation indices of FM signals.

Channel encoding is based on a convolutional code at different code rates and GMSK modulation defined for GSM.

A more recent technique based on this method is Hoffmann's modulation contrast, a system found on inverted microscopes for use in cell culture.

* Interferometric modulator display ( IMOD ) applications in consumer electronics ( primarily displays for mobile devices ), used to create interferometric modulation − reflective display technology as found in mirasol displays

To maintain compatibility with the existing AMPS cellular telephone system, the primary forward and reverse control channels in IS-54 cellular systems use the same signaling techniques and modulation scheme ( binary FSK ) as AMPS.

It is this modulation which reveals to Jacoby his own frightful abjection and, simultaneously, his wife's infidelity.

Another method of conveying an analog signal is to use modulation.

Contrast this with frequency modulation, in which the frequency is varied, and phase modulation, in which the phase is varied.

Amplitude modulation resulting in two sidebands and a carrier is called " double-sideband amplitude modulation " ( DSB-AM ).

Amplitude modulation is inefficient in power usage ; at least two-thirds of the power is concentrated in the carrier signal, which carries no useful information ( beyond the fact that a signal is present ).

This is single-sideband modulation, widely used in amateur radio and other communications applications.

However, there is no one-to-one correspondence between words in ASL and English, and the inflectional modulation of ASL signs — a dominant part of the grammar — is lost.

Amplitude modulation ( AM ) is used, and the conversation is performed in simplex mode.

Ring modulation, also known as amplitude modulation, is an effect made famous by Doctor Who's Daleks and commonly used throughout sci-fi.

Scarlatti's style, however, is more than a transitional element in Western music ; like most of his Naples colleagues he shows an almost modern understanding of the psychology of modulation and also frequently makes use of the ever-changing phrase lengths so typical of the Napoli school.

A channel actually consists of two signals: the picture information is transmitted using amplitude modulation on one frequency, and the sound is transmitted with frequency modulation at a frequency at a fixed offset ( typically 4. 5 to 6 MHz ) from the picture signal.

Note that the RF signal modulation is inverted compared to the conventional AM: the minimum video signal level corresponds to maximum carrier amplitude, and vice versa.