Digital delay lock circuits and methods for operating digital delay lock circuits are provided. A phase detector is configured to receive first and second clock signals and generate a digital signal indicating a relationship between a phase of the first clock signal and a phase of the second clock signal. A phase accumulator circuit is configured to receive the digital signal and generate a phase signal based on values of the digital signal over multiple clock cycles. A decoder is configured to receive the phase signal and generate a digital control word based on the phase signal. A delay element is configured to receive the digital control word. The delay element is further configured to change the relationship between the phase of the first clock signal and the phase of the second clock signal by modifying the phase of the second clock signal according to the digital control word.

Digital delay lock circuits and methods for operating digital delay lock circuits are provided. A phase detector is configured to receive first and second clock signals and generate a digital signal indicating a relationship between a phase of the first clock signal and a phase of the second clock signal. A phase accumulator circuit is configured to receive the digital signal and generate a phase signal based on values of the digital signal over multiple clock cycles. A decoder is configured to receive the phase signal and generate a digital control word based on the phase signal. A delay element is configured to receive the digital control word. The delay element is further configured to change the relationship between the phase of the first clock signal and the phase of the second clock signal by modifying the phase of the second clock signal according to the digital control word.

A circuit device includes a phase comparator that performs phase comparison between an input signal based on an oscillation signal and a reference signal, a processor that performs a digital signal process on phase comparison result data which is a result of the phase comparison so as to generate frequency control data, and an oscillation signal generation circuit that generates the oscillation signal having an oscillation frequency which is set on the basis of the frequency control data. The processor performs the digital signal process by using data used when a hold-over state is ended in a case where the hold-over state occurs due to the absence or the abnormality of the reference signal, and then the hold-over state is ended.

A circuit device includes a phase comparator that performs phase comparison between an input signal based on an oscillation signal and a reference signal, a processor that performs a digital signal process on phase comparison result data which is a result of the phase comparison so as to generate frequency control data, and an oscillation signal generation circuit that generates the oscillation signal having an oscillation frequency which is set on the basis of the frequency control data. The processor performs the digital signal process by using data used when a hold-over state is ended in a case where the hold-over state occurs due to the absence or the abnormality of the reference signal, and then the hold-over state is ended.

A circuit device includes a phase comparator that performs phase comparison between an input signal based on an oscillation signal and a reference signal, a processor that performs a signal process, and an oscillation signal generation circuit that generates the oscillation signal having an oscillation frequency which is set on the basis of frequency control data from the processor. The circuit device also includes at least one of a first register that stores phase comparison result data, a second register in which one of offset adjustment data for GPS and offset adjustment data for UTC is set, and a third register in which offset adjustment data for adjusting a phase difference is set.

A circuit device includes a phase comparator that performs phase comparison between an input signal based on an oscillation signal and a reference signal, a processor that performs a signal process on frequency control data based on a result of the phase comparison, and an oscillation signal generation circuit that generates the oscillation signal having an oscillation frequency which is set on the basis of frequency control data having undergone the signal process. The phase comparator includes a counter that performs a count operation by using the input signal, and performs the phase comparison by comparing a count value in the counter inn (where n is an integer of 2 or more) cycles of the reference signal with an expected value of the count value in integers.

A circuit device includes a phase comparator that performs phase comparison between an input signal based on an oscillation signal and a reference signal, a processor that performs a signal process on frequency control data based on a result of the phase comparison, and an oscillation signal generation circuit that generates the oscillation signal having an oscillation frequency which is set on the basis of frequency control data having undergone the signal process. The phase comparator includes a counter that performs a count operation by using the input signal, and performs the phase comparison by comparing a count value in the counter inn (where n is an integer of 2 or more) cycles of the reference signal with an expected value of the count value in integers.

A processing apparatus includes an FPGA unit connected to an oscillator configured to output a first clock, wherein the FPGA unit includes: a PLL circuit configured to output a second clock with a frequency of a predetermined ratio with respect to a frequency of the first clock and configured to output a lock signal (detection signal); an input and output monitoring unit configured to detect a ratio between the frequencies of the first clock and the second clock, compare the detected ratio with the predetermined ratio, and output an abnormal signal when the detected ratio does not coincide with the predetermined ratio; and an initialization unit configured to output a reset signal when the input and output monitoring unit outputs the abnormal signal and configured to output the reset signal when the PLL circuit outputs the lock signal.

A processing apparatus includes an FPGA unit connected to an oscillator configured to output a first clock, wherein the FPGA unit includes: a PLL circuit configured to output a second clock with a frequency of a predetermined ratio with respect to a frequency of the first clock and configured to output a lock signal (detection signal); an input and output monitoring unit configured to detect a ratio between the frequencies of the first clock and the second clock, compare the detected ratio with the predetermined ratio, and output an abnormal signal when the detected ratio does not coincide with the predetermined ratio; and an initialization unit configured to output a reset signal when the input and output monitoring unit outputs the abnormal signal and configured to output the reset signal when the PLL circuit outputs the lock signal.

An oscillator circuit includes an oscillating unit, a counter unit, and a set value generator. The oscillating unit is configured to output an oscillation signal having a frequency corresponding to an input frequency setting value. The counter unit is configured to count a number of pulses of the oscillation signal during a time period corresponding to a period of a reference signal input from outside. The set value generator is configured to generate the frequency setting value every predetermined time period based on the count of the pulses counted by the counter unit.