Delay measurement system and measurement method

A delay measurement system, comprising:

• a controller, configured to determine a first set of step delays and a second set of step delays, wherein an average of the second step delay is smaller than an average of the first step delay;
• a delay control device, configured to generate a second signal in response to a first signal, wherein the second signal delays a first delay time with respect to the first signal;
• a first delay controlled delay line (DCDL) device, configured to generate a fourth signal in response to the first signal, wherein the fourth signal delays a first offset time with respect to the first signal when a first output signal of the comparator is risen, a third signal is generated by a device under test (DUT) external to the first DCDL device in response to the fourth signal, and the first offset time is configured to align the rising edges of the second signal and the third signal;
• and
• a comparator, configured to compare the first delay time with a second delay time, wherein the third signal delays the second delay time with respect to the first signal, wherein:
• the delay control device is configured to perform at least one first tune on the first delay time based on the first set of step delays to approximate the first delay time, and perform at least one second tune on the first delay time based on the second set of step delays to approximate the first delay time, the first output signal of the comparator is risen when the second delay time is smaller than the first delay time.

A measurement method, comprising:

• determining a first set of step delays and a second set of step delays, wherein an average of the second step delay is smaller than an average of the first step delay;
• generating a second signal by a delay control device in response to a first signal, wherein the second signal delays a first delay time with respect to the first signal;
• generating a third signal by a device under test (DUT) external to a first delay controlled delay line (DCDL) device in response to a fourth signal generated by the first DCDL device, wherein the fourth signal is generated when a first output signal of a comparator is risen, the third signal delays a second delay time with respect to the first signal, and the fourth signal delays a first offset time with respect to the first signal;
• when the first delay time is not smaller than the second delay time, decreasing the first delay time based on the first set of step delays until the first delay time is smaller than the second delay time;
• when the first delay time is not greater than the second delay time, increasing the first delay time based on the second set of step delays until the first delay time is greater than the second delay time;
• and
• saving the first delay time.