In simple terms, the "louder" the modulating signal is, the more the carrier frequency changes. For illustration, suppose Fc is 1000 Hz. Modulation amplitude might be applied that causes the carrier to swing between 900 Hz and 1100 Hz, that is, 100 Hz in either direction. This is termed a "deviation" of 100 Hz.
Other practical benefits include the ability to transpose music without changing its duration, to change its tempo without changing its pitch, or change the synthetic instruments used to perform the piece of music. Drawbacks include the inability to easily include a recorded voice part or played instrument along with the MIDI sequenced sound, but on the other hand, the music can be easily synchronized with multimedia events in a production.
Frequency Modulation: radio en FM synthesis
FM synthesis is a form of "distortion synthesis" or "nonlinear synthesis". It begins with an oscillator generating an audio-frequency "carrier" waveform with a frequency of Fc. An audio-frequency modulating waveform, with a frequency Fm, is then applied to change or "modulate" the frequency of the carrier oscillator.
LAYER PAGES - Oscillator Frequency Modulation
Rather than using specific hardware, relatively ordinary PCs with popular sound cards have the ability to emulate oscillators, ADSRs, filters, frequency modulators, samplers, etc in real time. The generic nature of PCs allows users to connect up virtual synthesiser components in many familiar and totally new ways via intuitive user interfaces. The result can be very impressive, for instance it's hard to tell the difference between a real minimoog and a virtual minimoog created in Native-Instruments Generator software. Synthesiser components can be selected from menus, dragged around, inter-connected and assigned virtual controllers such as knobs and sliders.
FM stands for Frequency Modulation
If the modulator is at the same frequency as the carrier increasing the strength of the modulation produces a sawtooth wave. If the frequency is double that of the carrier wave the result is a square wave. No integer relationships produce bell tone and inharmonc sounds. This was a first for synthesizers.
Frequency modulation - Aalborg Universitet
What Dr Chowning had discovered was that if the carrier wave and the modulator wave were both in the audio range increasing the strength of the modulator created sidebands or harmonics on both sides of the carrier wave, Further more when he folded the side bands below the carrier to a corresponding frequency above the result was a musical harmonic series.
/chapter: Frequency-Modulation / PURE DATA
The idea is that you can create an out-of-phase wave with the same frequency that will interfere with your basic waveform and "warp" it, removing the "perfect", or flat tone from it.
The array contains frequency modulation functions, you can use them however you'd wish, but always apply at the end - it contains your carrier wave, and acts as a way to normalize all of the interference you create by combining and modulating other waveforms.
Our final waveform is a modulated combination of our initial waveform interfering with two "quieter" versions of itself, one at 75% amplitude, and the other at 10% amplitude, both slightly out-of-phase with their parent.
Finally, we multiply , our dampened amplitude, by our final waveform to finish creating our note.