How many forms of Jitter can you identify?

The worst forms of jitter are non-random (by far)!

If a disc wobbles while it spins then this may cause cyclical adjustments to the pick up laser servo and these repetitive draws on power may induce variations in the clock through the power supply.

IMHO, the most accurate or reliable approach is an asynchronous setup where the output clock is not synchronized to the input.

I'm absolutely positive that it isn't possible to apply a product to a CD that will have any effect on the digital clock on the CD player. I'm also skeptical that it can make any difference in how the CD player spins the disk so how does it reduce jitter? At most it should a good cleaning product that could allow the laser to read the disk better eliminating any error correction from being necessary.

What am I missing?
Mceljo

not true! Shadorne has hit upon the correct explanation altho' he gave yet another cause for jitter creation:

If a disc wobbles while it spins then this may cause cyclical adjustments to the pick up laser servo and these repetitive draws on power may induce variations in the clock through the power supply.

That's why that they have disk cutters (which re-cuts the outer edge of the disk with a sharp knife so as to smooth it & reduce/eliminate disk wobble).

You get the same random/spikey draws of current from the power supply when the laser light (trying to read the disk) reflects at funny angles off a dirty disk & after repeated reflections inside the laser transport box reaches the optical reader circuit. These multiple reflected rays of light are not the data from the disk but the optical reader knows no better & there are draws of current from the power supply as it tries to read this "data".
A power supply with lots of glitches tranfers these glitches to all the circuits are it is powering. So, in EE parlance we say that amplitude modulation (AM) on the power supply has created AM & PM (phase modulation) in the circuits being powered by that supply. Both AM & PM create jitter in the digital (music) signal being processed. This is one of the reasons you see multiple supplies in digital (CDP, transport, DAC, re-clockers) equipment & often it is prominently advertised. They are trying to prevent one corrupt sub-system from corrupting another...

07-19-11: Ericjcabrera
my buddy has a furutech demag that we use in addition to cleaning discs, and both of us, on both of our systems, can hear sonic improvements, sometimes significant on some cd's. how demagnetizing cd's affects player performance is beyond me, but i do know it works.

the CD disk is made of plastic & some organic dies that hold the digital data. The plastic structural material is not non-magnetic. Thus, when the laser light hits the plastic underside to read the data, over time the plastic gets mildly magnetized. For example, how many times have you experienced plastic packaging material "stick" to your fingers due to electro-static charge on it??? I'm sure many times...
The de-mag unit un-does this magnetization so that there is minimal/zero interaction between the mild magnet that the CD disk has become & the magnets inside the laser transport box.

The CD disk is made of plastic & some organic dies that hold the digital data. The plastic structural material is not non-magnetic. Thus, when the laser light hits the plastic underside to read the data, over time the plastic gets mildly magnetized. For example, how many times have you experienced plastic packaging material "stick" to your fingers due to electro-static charge on it???

Bombaywalla, I'm not sure I follow that. Static electrical charges and magnetization are two different things. And why would exposure to light cause either one?

Good point by Shadorne. Seconding Bombaywalla's comment about that point, it should be kept in mind that the extent to which that effect may be significant will be highly dependent on the design of the particular component.

Best regards,
-- Al