Modulation

Disciplines of Study [DoS]  >  Acoustics  ]

The process by which one signal is used to modify another. The controlled signal is referred to as the ’carrier’, and the controlling signal as the ’modulator’. It is of the greatest importance in both sound synthesis and signal processing.

The two main parameters of a sound to which modulation is commonly applied are those of amplitude (loudness) and frequency. Amplitude modulation of a signal causes changes in loudness in that signal. If the control signal is a slow regular waveform (e.g. a sine wave) the result is a tremolo - similar to (and often confused with) vibrato, except that there is no pitch deviation. Once the frequency of the modulator is raised above 10 to 15 Hz the tremolo amalgamates into a complex sound with added frequency components derived from the pitches of carrier and modulator. An irregular or transient control signal is generally associated with envelope generation.

Frequency modulation causes the pitch of the carrier to rise and fall according to the shape of the modulating waveform. If this is, as above, a slow regular waveform, the result is vibrato if the depth of the modulation is low, otherwise becoming a wide siren-like effect. If the modulating waveform is a series of discrete steps, the result is a series of discrete pitches. Particularly complex sounds arise when the frequency of the modulator is close to or even higher than that of the carrier. (Source - Richard Dobson (1992). A Dictionary of Electronic and Computer Music Technology. Oxford University Press.)

Ring modulation allows for the sum and difference of two input frequencies to be combined to create a new sound. Often one of these frequencies is at a sub-audio level allowing the creation of a sound of two similar frequencies, frequently with noisy textural characteristics.

 

See also:

Amplitude, Frequency, Frequency Modulation Synthesis

 

Bibliography:

English - Español - Français - Deutch - Italiano

Alphabetical order - Chronological order

Top

mail pharmacy lipitor in canada ciprofloxacin by ranbaxy bupropion cost metronidazole order cheap femalegra 100mg buy silagra in india omeprazole 30mg premarin http://sisyphe.info/?hat=830596 more info about buy azithrocin purchase tizan online prilosec over the counter buy vardenafil hcl lithosun sr usa drug enalapril tadacip in united states simvastatin 20 filagra info about flagyl without a prescription buy septra buy metronidazole flagyl http://www.revue-medias.com/?dft=12367 information baclofen 0.03 bimatoprost naltrexone 50 mg bactrim ds tabs amitriptyline hcl 25mg cost vasotec http://onpes.gouv.fr/?gav=858557 amlodipine besylate 10 in uk modalert 1200mg in united states http://mjz-57.fr/?her=491579 cabergoline piracetam capsuls buy modafinil fast in united states enalapril http://theatre-bourg.com/?fga=810182 methoxn ciprofloxacin 0.3 drops best price femara no presription buy ampicillin usa no perscription for azithromycin buy zocor 80 mg more info about norvasc medicine lipitor 15mg silagra 50 mg bactrim ds prescribing generic drugs for premarin http://offres.ro/?xxv=435678 http://www.wip-villette.com/?hah=759055 bupropion sr 100mg buy bupropion without prescription 20 mg doxycycline buy prednisolone