of Microprocessors

688 MUSICAL ApPLICATIONS OF MICROPROCESSORS
products (see Chapter 20), but the author is opposed to doing this in an
experimental synthesis system from three standpoints. First, common
graphics resolution in the 500 X 300 range and less is simply too low to
provide satisfactory rendition of all the various music score marks and still
show more than a few measures at once. Another is that the graphic score
tells what to play but very little about how to play it. Special conventions,
such as horizontal entry of one part at a time and a way to refer to voice
definitions, are necessary to insure that notes are matched with the proper
waveforms, envelopes, etc. While'this problem can certainly be overcome in a
system as simple as NOTRAN, one quickly becomes bogged down when
adapting conventional score notation to a more comprehensive synthesis
program. And finally, writing even a minimal score-editor program is a very
large task for an individual to tackle, certainly much larger than the
synthesis routines outlined so far. One can spend months or years to come up
with a good score editor before getting into the sound-synthesis programming
at all!
Keturning to the NOTRAN language as currently defined, it is in
many ways similar to a step-by-step procedural computer language like
FORTRAN or BASIC. Music code in the language is broken up into
individual statements.
Each statement uses one (or more) lines of text and almost always starts
with a keyword such as TEMPO or VOICE. The keywords, besides being easy
to read, make it easy for the interpreter to identify the type ofstatement. The
boundaries between statements either denote the passage of time or simply
separate blocks of information.
NOTRAN statement types can be divided into three different groups.
First, there is the specification group, which is used to define the characteristics
of something such as an "instrument." Specification statements are
instantaneous and do not consume any time in the musical performance.
Next, there are control statements, which influence what notes are to be
played and how they are to be played but again they do not consume any
time. Finally, there are note statements that actually cause sound to be
generated. Usually, but not always, a duration is associated with each note.
Later, we will discuss the importance of durations in sequencing and coordinating
multiple, simultaneous sounds. NOTRAN statements are executed
sequentially, one after another. The standard language has no provisions for
loops or repeats, etc.; that function is left for a Level 4 macroprocessor.
VOICE Statement
The VOICE statement is a specification statement used to define all of
the parameters associated with tone-type sounds. Thus, the envelope,
amplitude, and waveform parameters associated with tones must be