Jitter is an important part of SerDes systems specification. You can include jitter parameters from the SerDes Designer app. Including jitter impairment in your link and equalization design helps calculate the required eye margins. You can also perform trade-off between different equalization schemes based on total jitter contribution. You can export the jitter values to IBIS-AMI models.
The most common types of jitter are:
|DCD (duty cycle distortion)||Impairment from half and quarter rate clock misalignment. Also known as even-odd jitter. Defined here as the difference in symbol duration between one symbol and the next.|
|DJ (deterministic jitter)||Usually modeled as bounded uniform jitter. Also known as uncorrelated bounded high probability jitter. Defined here as half of the peak-to-peak variation.|
|RJ (random jitter)||Gaussian process that models unbounded jitter events. Also known as uncorrelated unbounded Gaussian jitter. Defined here as the standard deviation of a white Gaussian phase noise process.|
|SJ (sinusoidal jitter)||Bounded periodic jitter that typically comes from power supply voltage variation. Defined here as half of the peak-to-peak variation.|
|Noise||Random voltage noise. IBIS-AMI 7.0 defines Gaussian noise and uniform noise impairments. Also known as additive white Gaussian noise (AWGN).|
The expected simulation results vary depending on the type of jitter, injection site (transmitter or receiver), and analysis domain (statistical or time-domain). The SerDes Designer app only supports statistical or impulse-based analysis. The different types of jitter are injected into transmitter and receiver sites according to the IBIS-AMI specifications: