of Microprocessors

602 MUSICAL ApPLICATIONS OF MICROPROCESSORS
Table 17-1. Performance of a 64-Word 6-Bit Waveform Table
Harmonic number Desired amplitude Actual amplitude
0 --100 -48.67
1 -3 --3.14
2 -5 -5.13
3 -10 -10.28
4 -8 -8.27
5 -2 -2.02
6 0 -0.16
7 -4 -4.27
8 -10 -10.29
9 -15 -14.88
10 -19 -19.45
11 -10 -10.15
12 -5 -5.09
13 -1 -1.12
14 -6 -6.2
15 -12 -12.14
16 -20 -21.06
17-32 -100 -52.24 best
-36.72 worst
Ideal Actual Ideal Actual Ideal Actual
sample sample sample sample sample sample
values values values values values values
-0.051854 -0.0625 -0.181621 0.1875 -0.005724 0.0
0.249919 0.25 -0.182356 0.1875 0.243738 0.25
0.353100 0.34375 -0.174635 -0.1875 0.470721 0.46875
0.150009 0.15625 -0.383177 -0.375 0.463172 0.46875
0.072522 0.0625 -0.224204 -0.21875 0.248244 0.25
0.460679 0.46875 -0.106272 -0.09375 -0.028076 -0.03125
0.909300 0.90625 -0.463232 -0.46875 -0.353254 -0.34375
0,745635 0.71875 -0.999997 -0.96875 -0.720503 -0.71875
0.068102 0.0625 -0.990784 -0.96875 -0.903528 -0.875
-0.280506 -0.28125 -0.335606 -0.34375 -0.654850 -0.65625
0.090172 0.09375 0.217383 0.21875 -0.086723 -0.09375
0.536646 0.53125 0.136746 0.125 0.389132 0.375
0.334821 0.34375 -0.134930 -0.125 0.526439 0.5
-0.255813 -0.25 0.0744874 0.0625 0.424187 0.40625
-0.407391 -0.40625 0.585016 0.5625 0.319185 0.3125
0.058757 0.0625 0.643670 0.625 0.248252 0.25
0.452688 0.4375 0.0782302 0.0625 0.158014 0.15625
0.213340 0.21875 -0.486549 -0.46875 0.084257 0.09375
-0.364094 -0.34375 -0.559661 -0.5625 0.082703 0.09375
-0.584477 -0.5625 -0330236 -0.3125 0.070032 0.0625
-0.244755 -0.25 -0.151069 -0.15625 -0.058026 -0.0625
-0.177100 -0.1875
where it is easily heard. Historically, harmonic distortion ratings were used
because they were easy to measure and correlate well with 1M readings,
which are a much better measure of subjective distortion. Although direct
1M measurements are now easily performed, tradition requires that harmonic
distortion still be quoted on spec sheets.