LinPlug Spectral - Manual (Page 91)

(less than 20 Hz) vibrato is produced. When the modulation
frequency is within the audio range, Frequency Modulation
is produced.
Harmonics: Every waveform can – at a given time – be seen as a
fundamental wave (the base frequency) and a number of
harmonics. If there are no harmonics you have a simple
sine wave. Certain harmonics create certain well known
waveforms such as sawtooth or pulse. In Spectral
waveforms can be constructed from the fundamental up to
the 256th harmonic.
LFO: An LFO or Low Frequency Oscillator is a periodic signal
source (usually below audio frequency range) used to
modulate another module's parameter. An LFO can be
used for a variety of effects including vibrato (by modulating
the pitch) and tremolo (by modulating the volume).
Oscillator: A signal source that generates a periodic waveform at a
given frequency.
Patch or A Patch is another word for Preset or Sound Program, that
Preset: is, the complete data making up a certain sound as it is
editable on the Spectral's user interface. You can save
sound programs (see page 78) and later load them using
the Preset Browser (see page 77).
PM or Phase Modulation is a kind of cross-modulation, meaning
Phase that the Oscillator being modulated changes its Phase not
Modulation only according to its pitch but also in relation to the
Modulator (the Oscillator modulating this one). Thus, the
Phase usually changes forth and back and produces
additional harmonics, similar to FM modulation.