What is jitter and how does it affect audio quality?
In the audio field the term jitter designates a timing uncertainty of digital clock signals. E.g. in an Analog to Digital Converter (A/D) the analog signal is sampled (measured) at regular time intervals; in the case of a CD, 44,100 times a second or every 22.675737 microseconds. If these time intervals are not strictly constant then one talks of a jittery conversion clock. In practice it is of course not possible to generate exactly the same time interval between each and every sample. After all, even digital signals are analog in their properties and thus are influenced by noise, crosstalk, power supply fluctuations, temperature etc. Hence a jittery clock introduces errors to the measurements taken by the A/D, resulting from measurements being taken at the wrong time. One can easily observe that the level of the error introduced is higher during high audio frequencies, because high frequency signals have a steeper signal form. A good designer takes care that the jitter amount in his/