Data-dependent jitter is a specific class of timing jitter

Jitter

Jitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source. Jitter may be observed in characteristics such as the frequency of successive pulses, the signal amplitude, or phase of...

. In particular, it is a form of deterministic jitter

Deterministic jitter

Deterministic jitter is a type of jitter with a known non-Gaussian probability distribution. The other major class of jitter is non-deterministic, or random jitter.-Characteristics:...

 which is correlated with the sequence of bits in the data stream. It is also a form of ISI

Intersymbol interference

In telecommunication, intersymbol interference is a form of distortion of a signal in which one symbol interferes with subsequent symbols. This is an unwanted phenomenon as the previous symbols have similar effect as noise, thus making the communication less reliable...

.

Properties

Depending on characteristics of the signal

Analog signal

An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...

 and transmission

Transmission line

In communications and electronic engineering, a transmission line is a specialized cable designed to carry alternating current of radio frequency, that is, currents with a frequency high enough that its wave nature must be taken into account...

 topology, previously transmitted symbols can affect the edge cross over time. This creates a probability distribution

Probability distribution

In probability theory, a probability mass, probability density, or probability distribution is a function that describes the probability of a random variable taking certain values....

 for the timing of the signal edge, which is usually recorded in a PDF

Probability density function

In probability theory, a probability density function , or density of a continuous random variable is a function that describes the relative likelihood for this random variable to occur at a given point. The probability for the random variable to fall within a particular region is given by the...

.

DDJ's PDF

Probability density function

In probability theory, a probability density function , or density of a continuous random variable is a function that describes the relative likelihood for this random variable to occur at a given point. The probability for the random variable to fall within a particular region is given by the...

 is always a series of pulses

Pulse (signal processing)

In signal processing, the term pulse has the following meanings:#A rapid, transient change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value....

 at the locations where a specific bit pattern experiences a cross over

Crossover distortion

Crossover distortion is a type of distortion which is caused by switching between devices driving a load, most often when the devices are matched...

. Therefore, in order to get an accurate measure of the DDJ in a particular system, a large number of bit patterns must be analyzed (often just a PRBS) unless an analytical solution can be found.