Wave
A wave is the digitally stored image of a single wave cycle. From this point of view a wave
is identical to a sample that is looped exactly after one cycle. The difference to a sampler or
ROM sample player is that all waves have the same length and they are played at the same
pitch. A typical wave looks like this:
The diagram shows the symmetry of the waveform which is mirrored in its middle. In fact
most waves in the MicroWave II/XT/XTk are made up in this way so that only the first half
of the cycle is stored in memory. The MicroWave II/XT/XTk calculates the missing part on
its own. At this point we see one extension to the classic PPG systems and the first
MicroWave: The MicroWave II/XT/XTk can also store whole wave cycles. This feature
becomes interesting in all those cases where analog-type waveforms with different pulse
width or additive created waveforms with different phase shifts of the harmonics should be
generated. These sophisticated timbres were especially not realizable with the first
generation wavetable synthesizers.
Wavetable
In fact a wavetable does not consist of waves but of references to them. The MicroWave
II/XT/XTk stores wavetables and waves separately, numbered from 001…128 for the
wavetables , 000…299 for the waves and 1000…1249 for the user waves.
In a wavetable up to 64 of these references are combined, each pointing at one of the 500
waves. The term "up to 64" means that a wavetable can contain even less references. In this
case the missing entries are filled automatically by the MicroWave II/XT/XTk as soon as the
wavetable is selected. At least 5 references must be present in every wavetable, one at the
first position and 4 at the last. Three of the four positions represent – as already described
above – the classic synthesizer waveforms triangle, pulse and sawtooth.
E.g. the wavetable shown below contains references to waves at positions 00, 02, 05, 60
plus the three classic waves at positions 61…63. We will ignore these three last ones for
now.
Wave 63
Wave 62
Wave 61
Wave 60
Wave 05
Wave 04
Wave 02
Wave 01
Wave 00
Wave 03
User’s Manual MicroWave II • MicroWave XT • XTk
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