4.1.10 Rate encoding

Rate encoding is the modulation of the frequency of repetitive events in order to imply amplitude changes in another domain; it is similar to frequency modulation, but instead of reflecting the frequency of a sinusoid, it is the frequency of some specified event. Conductors use rate encoding (often in the form of subdivisions within the beat pattern) to specify intensity or dynamic changes. For example, in a segment from subject P1, he starts the crescendo by increasing the amplitude of EMG tension with his right arm, then adds left arm, and then doubles the frequency of his beats for the last two bars. That is, instead of giving beats in a meter of one for every two quarter-notes, he gave beats in a meter of two. The example of rate encoding in Figure 37 corresponds with measures 5-8 after A in Tchaikovsky’s score to the Symphony no. 6; P1’s EMG0 signal shows the left biceps signal and EMG2 signal reflects the right biceps.

Figure 37. Rate encoding evidenced in P1’s beat signals compared with the score

 Chapter 4.1.11