A jitter generator may include a duty cycle code generator that generates a duty cycle control signal and an input buffer that outputs a signal based on its duty cycle. The input buffer may be coupled to the duty cycle code generator and to a source of a clock signal. After receiving the clock signal, the input buffer outputs the clock signal having jitter relative to the clock signal received from the source. The jitter may be added at least in part by components of the input buffer offsetting different transitions of the clock signal according to the duty cycle. Jitter may be added when the duty cycle changes in response to changes in the duty cycle control signal, such as in response to number generator circuitry of the duty cycle code generator update its output number, in response to a mode change received from a controller, or the like.