DIGITAL DATA SLICING CIRCUIT AND SLICING METHOD
A digital data slicing circuit and a method for slicing digital data are provided. The digital data slicing circuit comprises a slicer, a phase locked loop (PLL), a data jitter circuit, and a level calculator. Wherein, the slicer receives a RF signal and a slicing level and outputs a digital signal. The PLL provides a PLL clock based on the received digital signal. The data jitter circuit obtains a jitter signal by comparing the digital signal with the PLL clock, and outputs a jitter error signal by performing a jitter calculation with the jitter signal, the digital signal, and the PLL clock. The level calculator receives the jitter error signal and adjusts and outputs the slicing level.
1 . A digital data slicing circuit receiving an RF signal, and the digital data slicing circuit comprising:
a slicer receiving the RF signal and a slicing level for outputting a digital signal;
a Phase Locked Loop (PLL), electrically coupled to the slicer for receiving the digital signal and outputting a PLL clock based on the received digital signal;
a data jitter circuit, electrically coupled to the slicer and the PLL for receiving the digital signal and the PLL clock and obtaining a jitter signal by comparing the digital signal with the PLL clock, and outputting a jitter error signal by performing a jitter calculation with the jitter signal, the digital signal, and the PLL clock; and
a level calculator, electrically coupled to the data jitter circuit for receiving the jitter error signal and adjusting and outputting the slicing level.
2 . The digital data slicing circuit of claim 1 , wherein the slicer comprises:
a digital-to-analog (D/A) converter for receiving the slicing level and converting the received slicing level into an analog signal; and
a comparator having a positive input terminal and a negative input terminal, wherein the positive input terminal receives the RF signal, the negative input terminal receives the slicing level, and the comparator slices the RF signal based on the slicing level and outputs the digital signal.
3 . The digital data slicing circuit of claim 1 , wherein the slicer comprises:
an analog-to-digital (A/D) converter for receiving the RF signal and converting the received RF signal into a digital signal; and
a comparator having a positive input terminal and a negative input terminal, wherein the positive input terminal receives the digitalized RF signal, the negative input terminal receives the slicing level, and the comparator slices the RF signal based on the slicing level and outputs the digital signal.
4 . The digital data slicing circuit of claim 1 , further comprising:
an alternative level generator for generating an alternative slicing level; and
a multiplexer, electrically coupled to the alternative level generator and the level calculator for switching between the alternative level generator and the level calculator according to a mode selection signal.
5 . The digital data slicing circuit of claim 1 , wherein when a result from the jitter calculation is less than ½ cycle of two contiguous PLL clocks, the jitter signal is outputted.
6 . The digital data slicing circuit of claim 5 , wherein the jitter calculation measures a cycle of zero-cross from the PLL clock to the digital signal.
7 . The digital data slicing circuit of claim 6 , wherein the jitter calculation further measures a cycle from the zero-cross of the digital signal to the PLL clock.
8 . A method for slicing digital data, comprising:
receiving an RF signal and a slicing level and outputting a digital signal based on the received RF signal and the slicing level;
receiving the digital signal and outputting a PLL clock based on the received digital signal;
receiving the digital signal and the PLL clock, obtaining a jitter signal by comparing the received digital signal with the PLL clock, and outputting a jitter error signal by performing a jitter calculation with the jitter signal, the PLL clock, and the digital signal; and
receiving the jitter error signal and adjusting and outputting the slicing level.
9 . The method for slicing digital data of claim 8 , wherein the step of receiving the RF signal and the slicing level and outputting the digital signal based on the received RF signal and the slicing level comprises:
receiving the slicing level, and converting the slicing level into an analog signal; and
slicing the RF signal based on the slicing level and outputting the digital signal.
10 . The method for slicing digital data of claim 8 , wherein the steps of receiving the RF signal and the slicing level and outputting the digital signal based on the received RF signal and the slicing level comprise:
receiving the RF signal, and converting the RF signal into a digital signal; and
slicing the RF signal based on the slicing level and outputting the digital signal.
11 . The method for slicing digital data of claim 8 , wherein when a result from the jitter calculation is less than ½ cycle of two contiguous PLL clocks, the jitter signal is outputted.
12 . The method for slicing digital data of claim 11 , wherein the jitter calculation measures a cycle of zero-cross from the PLL clock to the digital signal.
13 . The method for slicing digital data of claim 12 , wherein the jitter calculation further measures a cycle from the zero-cross of the digital signal to the PLL clock.