The LP-PSOLAR algorithm uses a the Linear Prediciton Coding (LPC) to calculate an error vector from a signal. This error vector is used to calculate the pitch markers. What do these pitch markers represent in the original signal in generall? Do they represent a change in fundamental frequency or a change in phoneme (I think both assumptions are wrong)? The following figure depicts the error vector (red) and the signal (green). The second picture depicts an additional example.
The pitch marker indicates the beginning of each cycle of the waveform - or from a more physiological point of view the point at each the periodical motion of the glottis causes a sudden change in air flow.
A stable sound (in pitch and phoneme) will still have a marker every cycle - so these markers do not indicate any change.
Interesting post, I'm working on the same, your plot seems to be catching the valeys Marks, I did the same using Pitch Track based in autocorrelation, but my marks are in Peaks (Maximum excitation of signal).
For my first test I'm using "Kara.segment1.aiff" from Peeter's page, here my plot marks :
When you speech there is a moment where your glottis are closed and other instant where it is open, this moments are find by Pitch Markers, is interesting see how glottis have relation witch Pitch Period, you can get near values of pitch using Pitch Markers.
You can see how near they are, for this plot I get:
Period extracted from Pitch Track (Autocorerlation Based):
395 379 365 359 355 349 342 337 332 329 325 322 319 316 314 312 310 306 302 304 311
Period extracted from Pitch Mark using Peaks:
393 381 368 364 343 348 345 340 327 328 325 323 320 316 317 198 312 426 297 329 299
