Signal receiver and slicer
A signal receiver and a slicer are capable of mitigating the static mismatch error of a far-end digital-to-analog converter. The slicer includes an adjustable slicing circuit and an error signal generating circuit. The adjustable slicing circuit determines which of (N+1) signal levels is corresponding to an input signal according to N slicer levels and thereby outputs an output signal, wherein the input signal is originated from the far-end digital-to-analog converter. The adjustable slicing circuit further adjusts at least some of the (N+1) signal levels according to an error signal and adjusts at least some of the N slicer levels, wherein the N is an integer greater than two. The error signal generating circuit is coupled to the adjustable slicing circuit and generates the error signal according to the input and output signals.
1. A signal receiver capable of mitigating a static mismatch error of a far-end digital-to-analog converter (far-end DAC), the signal receiver comprising:
an analog-front-end (AFE) circuit configured to generate an analog signal according to a received signal originated from the far-end DAC;
an analog-to-digital converter (ADC) configured to generate a digital signal according to the analog signal;
an equalizer circuit configured to generate an input signal according to the digital signal;
an adjustable slicing circuit configured to determine which level of (N+1) signal levels is corresponding to the input signal according to N slicer levels and thereby generate an output signal, and the adjustable slicing circuit further configured to adjust at least a part of the (N+1) signal levels according to an error signal and adjust at least a part of the N slicer levels, wherein the N is an integer greater than two; and
an error signal generating circuit coupled to the adjustable slicing circuit and configured to generate the error signal according to the input signal and output signal.
2. The signal receiver of claim 1 , wherein the error signal is equal to a difference between the input signal and the output signal.
3. The signal receiver of claim 1 , wherein the adjustable slicing circuit leaves at least two signal levels of the (N+1) signal levels unchanged.
4. The signal receiver of claim 3 , wherein the at least two signal levels are an (N+1) th signal level and a first signal level respectively; the (N+1) th signal level is a maximum signal level of the (N+1) signal levels; and the first signal level is a minimum signal level of the (N+1) signal levels.
5. The signal receiver of claim 1 , wherein when a level of the output signal is a K th signal level of the (N+1) signal levels, the adjustable slicing circuit adjusts the K th signal level according to the error signal and then adjusts at least one target slicer level of the N slicer levels neighboring the K th signal level according to a K th cumulative adjustment amount of the K th signal level; and the K is a positive integer between 1 and (N+1).
6. The signal receiver of claim 5 , wherein the K th cumulative adjustment amount is equal to a current value of the K th cumulative adjustment amount plus a coefficient multiplied by the error signal.
7. The signal receiver of claim 5 , wherein when the level of the output signal is the K th signal level and the K is less than (N+1), the adjustable slicing circuit adjusts the K th signal level according to the error signal first, and then adjusts an upper target slicer level of the N slicer levels between the K th signal level and a (K+1) th signal level of the (N+1) signal levels according to the K th signal level and the (K+1) th signal level.
8. The signal receiver of claim 7 , wherein the adjustable slicing circuit adjusts the upper target slicer level through following calculation: adding up an initial value of the upper target slicer level and an average of the K th cumulative adjustment amount and a (K+1) th cumulative adjustment amount of the (K+1) th signal level.
9. The signal receiver of claim 5 , wherein when the level of the output signal is the K th signal level and the K is greater than one, the adjustable slicing circuit adjusts the K th signal level according to the error signal first, and then adjusts a lower target slicer level of the N slicer levels between the K th signal level and a (K−1) th signal level of the (N+1) signal levels according to the K th signal level and the (K−1) th signal level.
10. The signal receiver of claim 9 , wherein the adjustable slicing circuit adjusts the lower target slicer level through following calculation: adding up an initial value of the lower target slicer level and an average of the K th cumulative adjustment amount and a (K+1) th cumulative adjustment amount of the (K+1) th signal level.
11. A slicer capable of mitigating a static mismatch error of a far-end digital-to-analog converter (far-end DAC), the slicer comprising:
an adjustable slicing circuit configured to determine which level of (N+1) signal levels is corresponding to an input signal according to N slicer levels and thereby generate an output signal, and the adjustable slicing circuit further configured to adjust at least a part of the (N+1) signal levels according to an error signal and adjust at least a part of the N slicer levels, wherein the input signal is originated from the far-end DAC and the N is an integer greater than two; and
an error signal generating circuit coupled to the adjustable slicing circuit and configured to generate the error signal according to the input signal and output signal.
12. The slicer of claim 11 , wherein the error signal is equal to a difference between the input signal and the output signal.
13. The slicer of claim 11 , wherein the adjustable slicing circuit leaves an (N+1) th signal level and a first signal level of the (N+1) signal levels unchanged, the (N+1) th signal level is a maximum signal level of the (N+1) signal levels; and the first signal level is a minimum signal level of the (N+1) signal levels.
14. The slicer of claim 11 , wherein when a level of the output signal is a K th signal level of the (N+1) signal levels, the adjustable slicing circuit adjusts the K th signal level according to the error signal and then adjusts at least one target slicer level of the N slicer levels neighboring the K th signal level according to a K th cumulative adjustment amount of the K th signal level;
and the K is a positive integer between 1 and (N+1).
15. The slicer of claim 14 , wherein the K th cumulative adjustment amount is equal to a current value of the K th cumulative adjustment amount plus a coefficient multiplied by the error signal.
16. The slicer of claim 14 , wherein when the level of the output signal is the K th signal level, the K is less than (N+1), and the K is greater than one, the adjustable slicing circuit adjusts the K th signal level according to the error signal, and then adjusts two target slicer levels of the N slicer levels neighboring the K th signal level according to the K th cumulative adjustment amount.
17. The slicer of claim 14 , wherein when the level of the output signal is the K th signal level and the K is less than (N+1), the adjustable slicing circuit adjusts the K th signal level according to the error signal first, and then adjusts an upper target slicer level of the N slicer levels between the K th signal level and a (K+1) th signal level of the (N+1) signal levels according to the K th signal level and the (K+1) th signal level.
18. The slicer of claim 17 , wherein the adjustable slicing circuit adjusts the upper target slicer level through following calculation: adding up an initial value of the upper target slicer level and an average of the K th cumulative adjustment amount and a (K+1) th cumulative adjustment amount of the (K+1) th signal level.
19. The slicer of claim 14 , wherein when the level of the output signal is the K th signal level and the K is greater than one, the adjustable slicing circuit adjusts the K th signal level according to the error signal first, and then adjusts a lower target slicer level of the N slicer levels between the K th signal level and a (K−1) th signal level of the (N+1) signal levels according to the K th signal level and the (K−1) th signal level.
20. The slicer of claim 19 , wherein the adjustable slicing circuit adjusts the lower target slicer level through following calculation: adding up an initial value of the lower target slicer level and an average of the K th cumulative adjustment amount and a (K+1) th cumulative adjustment amount of the (K+1) th signal level.