definition of cd jitter, what is it?

so im totally down with cd errors and c1/c2 error correction, all that stuff.

but what is jitter?

ta

tristo

 

hrmm.... jitter jitter jitter!

 

This might help and is a good read and poises some interesting tests on Audio Quality from CD's

Excerpt from this link http://www.stereophile.com/reference/590jitter/index2.html

The most likely source of audible changes in digital audio is jitter, a time-axis variation in the digital bitstream. Jitter is most often introduced by mechanical imperfections in digital audio-storage devices. A CD player's rotational servo, for example, can introduce time-base errors (jitter) in the recovered signal if its speed varies even by a tiny amount. Another example of a jitter-inducing mechanism is a digital tape transport. The speed variations which introduce jitter have an analog counterpart in wow and flutter. Jitter can also create bit errors if severe enough, although this is uncommon.

Fig.5 shows the effects of jitter on digital code. Jitter changes the position where a transition in the digital signal occurs. It has all the right information and in the right order, but skewed in time.



Fig.5 Jitter affects the time relationship between digital transitions. (Reproduced from Principles of Digital Audio, Second Edition (1989), by Kenneth C. Pohlmann, with the permission of the publisher, Howard W. Sams & Company.)

If you have ever watched a multiple-generation VHS video tape, you've seen the effects of time-base error, which is analogous to digital audio jitter. With each successive generation, the horizontal lines that make up the picture become increasingly skewed in relation to each other. As this time-base error accumulates, image outlines become slightly crooked, making the picture appear fuzzy.

If jitter reaches the digital-to-analog converter, severe errors in the output analog signal result. Fig.6 shows how timing variations can affect the shape of an analog waveform. In theory, however, jitter is never allowed to reach the DAC: jitter-laden data are input to a buffer and clocked out with quartz-crystal accuracy to the DAC. Many engineers, including those at JVC who designed the K-2 Interface and digital designers at Madrigal Audio Laboratories, maintain that jitter can still reach the DAC, despite the buffering.

Hope that helps