Lexicon PCM 80, User Manual

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3-27
The Algorithms and Their Parameters
Mod: Sw 1 and Mod: Sw 2
These are identical time switches. Each has five parameters: Rate, P Width,
Mode, T Lvl and T Src.
Rate sets the speed at which the switch cycles. It can be set in
time values (such as 1.5 Hz) or tempo values (such as 3:2
Cycles per Beat). Simultaneously pressing Up and
Tempo will toggle these display options.
P Width determines the proportion of each switch cycle during
which the switch is on. For example, setting P Width to
50% means that the switch is on for one-half of a cycle.
Mode determines the “shape” of the switch output. Three set-
tings are available: Switch, Ramp, and Off. When Switch
is selected, the transition from on to off is instantaneous,
i.e. the switch output resembles a pulse wave. When
Ramp is selected, the transition from on to off is continu-
ous, i.e. the switch output resembles a triangle or sawtooth
wave.
Off turns the switch off (and frees up processor time). To
optimize PCM 80 real-time response, set switch to Off
when it is not being used.
T Lvl sets the threshold value at which the switch will begin to
cycle.
T Src selects a patch source to drive the switch. The output of the
switch is 0 as long as T Src is set to a value below T Lvl.
Once the source value reaches or passes T Lvl, the switch
will begin to cycle between on (127) and off (0) at the speed
set by Rate.
Note that both Rate and P Width are available as patch
Destinations, allowing them to be dynamically controlled
by other patch sources. Switches are reset to the begin-
ning of their cycles whenever Tap is pressed.
Modulation cont'd.