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+#X text 336 665 updated for Pd version 0.39;
+#X text 109 12 MORE ON MEASURING SPECTRA: HETERODYNING;
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+#X text 186 435 <-- responsiveness;
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+#X text 56 248 signal to;
+#X text 58 268 analyze;
+#X text 51 44 Another method for picking out the strengths of partials
+in a sound is heterodyning. We guess the frequency of a partial (as
+in the previous patch) but this time we multiply by a complex exponential
+to frequency-shift the partial down to zero (DC).;
+#X text 47 126 Then a low-pass filter (applied separately on the real
+and imaginary parts) removes all but the DC component thus obtained.
+The result is two audio signals (which we take snapshots of) holding
+the real and imaginary parts of the complex amplitude of the partial
+we want. Compared to the previous method \, this had the advantage
+of reporting the phase of the partial as well as its frequency.;
+#X text 240 358 modulate;
+#X text 237 394 to DC;
+#X text 154 321 <-- test frequency;
+#X text 236 376 test frequency;
+#X text 132 471 low-pass filter;
+#X text 55 596 real;
+#X text 59 611 part;
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+#X text 105 670 magnitude;
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