Abstract: A method for reducing a frequency error, including: applying a plurality of dither values to a local reference clock over a first time interval; sampling, during the first time interval and using the local reference clock, a first plurality of data values received over an asynchronous link, where the first plurality of data values are transmitted over the asynchronous link based on a remote reference clock; tracking a plurality of errors from sampling the first plurality of data values; and adjusting, based on the plurality of errors, a frequency of the local reference clock to reduce the frequency error between the local reference clock and the remote reference clock.

Abstract: A method for reducing a frequency error, including: applying a plurality of dither values to a local reference clock over a first time interval; sampling, during the first time interval and using the local reference clock, a first plurality of data values received over an asynchronous link, where the first plurality of data values are transmitted over the asynchronous link based on a remote reference clock; tracking a plurality of errors from sampling the first plurality of data values; and adjusting, based on the plurality of errors, a frequency of the local reference clock to reduce the frequency error between the local reference clock and the remote reference clock.

Abstract: The disclosure provides systems and methods for programmable fixed frequency digitally controlled oscillators for multirate low jitter frequency synthesis. The present invention utilizes a digital control element, such as a complex programmable logic device (CPLD) or field programmable gate array (FPGA), to monitor the frequency offset of a DCO with respect to one or more timing module (TM) references. The frequency offset is measured by aligning the phase of a DCO feedback divider to the phase of a reference divider, and then counting the number of pulses in the DCO between the falling edges of the feedback to determine a frequency error. Falling edge detection is used to determine a sign of the error. The digital control element then calculates a frequency correction based on a linear scaling factor to send a new control word to the DCO to reduce the frequency error.

Abstract: The disclosure provides systems and methods for programmable fixed frequency digitally controlled oscillators for multirate low jitter frequency synthesis. The present invention utilizes a digital control element, such as a complex programmable logic device (CPLD) or field programmable gate array (FPGA), to monitor the frequency offset of a DCO with respect to one or more timing module (TM) references. The frequency offset is measured by aligning the phase of a DCO feedback divider to the phase of a reference divider, and then counting the number of pulses in the DCO between the falling edges of the feedback to determine a frequency error. Falling edge detection is used to determine a sign of the error. The digital control element then calculates a frequency correction based on a linear scaling factor to send a new control word to the DCO to reduce the frequency error.