Detector array with time-to-digital conversion having improved temporal accuracy

摘要

A detector (22) detects an event. First and second time-to-digital converters (TDCs) (70, 72) generate first and second time stamps (TS1, TS2) for the detection of the event. The first TDC and the second TDC are both synchronized with a common clock signal (62) that defines a fixed time offset between the second TDC and the first TDC. An autocalibration circuit (120) adjusts the first TDC and the second TDC to keep the time difference between the second time stamp and the first time stamp equal to the fixed time offset between the second TDC and the first TDC. The detector may be a detector array, and trigger circuitry (28) propogates a trigger signal from a trigger detector of the array of detectors to the first and second TDC's. Skew correction circuitry (132, 134, 136, 142, 60, 162) adjusts a timestamp (TS) based on which detector is the triggering detector.

主权项

1. A method comprising:
(i) synchronizing a first time-to-digital converter (TDC) with a common clock signal; (ii) synchronizing a second TDC with the common clock signal wherein the synchronizing operations (i) and (ii) determine a fixed time offset of the second TDC respective to the first TDC as the period of the common clock signal or as a fixed fraction or multiple of the period of the common clock signal; detecting an event; generating a trigger signal associated with the detection of the event; generating a first time stamp for the trigger signal by measuring a first time interval using the first TDC and transforming the first time interval into the first time stamp using a first transform operation including multiplying by a multiplication factor; generating a second time stamp for the trigger signal by measuring a second time interval using the second TDC and transforming the second time interval into the second time stamp using a second transform operation including multiplying by the multiplication factor; associating a time stamp with the event based on the first time stamp and the second time stamp; and increasing or decreasing the multiplication factor to reduce any difference between (1) the time difference between the second time stamp and the first time stamp and (2) the fixed time offset.