Patch C08.analog.sequencer.pd (figure 3.15) realizes the analog sequencer and envelope
generation described in section 3.7. The ``sequence" table,
with nine elements, holds a sequence of frequencies. The
object at top cycles through the sequence table at 0.6 Hz. Non-interpolating
table lookup (
instead of
) is
used to read the frequencies in discrete steps. (Such situations, in
which we prefer non-interpolating table lookup, are rare.)
The
object converts the amplitude-9 sawtooth to a
unit-amplitude one as described earlier in Figure 3.8, which is
then used to obtain an envelope function from a second wavetable. This is
used to control grain size in a looping sampler
(from section 2.6.4). Here the ``sample" consists of six
periods of a sinusoid. The grains are smoothed by multiplying by a raised
cosine function (
and
1).
Patch C09.sample.hold.pd (not pictured here) shows a sample-and-hold unit, another useful device for doing control tasks in the audio signal domain.