| 摘要 |
The present disclosure is directed to a fractional-N digital phase locked loop (DPLL) that replaces the conventionally used time-to-digital converter (TDC) based phase detector with a bang-bang phase detector (BBPD). Compared to the TDC based phase detector, the BBPD has an often superior resolution for the same or similar amount of power and/or area consumption. Therefore, replacing the TDC based phase detector with a BBPD can reduce, or even eliminate, the common problem of spurs being added to the output signal generated by the DPLL because of the limited resolution of the TDC based phase detector. This can allow the DPLL to be used for the most demanding applications, such as in generating local oscillator signals for down-converting and demodulating weak signals received by a communication device, such as a cellular phone. |
