時間至數位轉換器為時間量測系統中相當重要的部分，在各式時間至數位轉換器中，以游標卡尺法能提供較高的量測解析度最具未來性。然而，傳統以游標卡尺法作為基礎的時間至數位轉換器，其使用之振盪器通常須經繁瑣的校準程序，因此使用上相當麻煩。有鑑於此，本文提出一新型軟注入鎖定環形振盪器作為時間至數位轉換器的時脈來源，當振盪器在觸發訊號出現時能快速起振，且穩定在預期頻率下。此外，本電路架構已由 TSMC 1P6M 0.18 m CMOS 製程驗證，由實驗結果顯示，時間至數位轉換器的量測解析度可小於正負1 LSB。

A time-to-digital converter (TDC) plays an important role in time interval measurement. Among various TDC
structures, the vernier-based TDC is promising because it can possess highly accurate time resolution. However, the
oscillators used in the conventional vernier-based TDC require complicated calibration procedure. This makes the
TDC diffi cult in use. In this paper, we purpose a new soft-injection-locked ring oscillator as the clock source for the
vernier-based TDC. The proposed oscillator can oscillate immediately and accurately right after the trigger signal
arrives. The TDC structure employing the purposed oscillators is verifi ed by the TSMC 0.18 m CMOS process.
Experimental results show that the equivalent resolution less than  1 LSB can be achieved.