Serializer-deserializer (SerDes) having a predominantly digital architecture and method of deserializing data
View Patent ↗A serializer-deserializer and a method of deserializing data. In one embodiment, the serializer-deserializer includes: (1) an analog-to-digital converter configured to receive a serial data stream and provide a digital output based thereon, (2) a digital comparator coupled to the analog-to-digital converter and configured to compare the digital output to an output table to yield candidate output bits, (3) a digital feedback equalizer coupled to the digital comparator and configured to generate the output table based on the candidate output bits and (4) a multiplexer coupled to the digital comparator and configured to select output bits from among the candidate output bits to form a discrete bit sequence.
1. A serializer-deserializer, comprising:
an analog-to-digital converter configured to receive a serial data stream and provide a digital output based thereon;
a digital comparator coupled to said analog-to-digital converter and configured to compare said digital output to an output table to yield candidate output bits;
a digital feedback equalizer coupled to said digital comparator and configured to generate said output table based on said candidate output bits; and
a multiplexer coupled to said digital comparator and configured to select output bits from among said candidate output bits to form a discrete bit sequence.
2. The serializer-deserializer as recited in claim 1 wherein said analog-to-digital converter includes:
an analog comparator matrix configured to compare a voltage of said serial data stream to various analog reference voltages;
a deserializer coupled to said analog comparator matrix and configured to deserialize an output thereof; and
a compactor coupled to said deserializer and configured to compact an output thereof.
3. The serializer-deserializer as recited in claim 1 wherein said candidate output bits are generated in accordance with DC t (i,j)=(ADC t (i)>EQT(i)), i=0, . . . , 2 K −1, j=0, . . . , M−1.
4. The serializer-deserializer as recited in claim 1 wherein said digital feedback equalizer is configured to carry out the following functions:
R 0 =0,
W t+1 [j ]=MUX K ( S t+1 ( j ), A t+1 ( j )), and
R t+1 =W,
where
A t +1( j )=(DC t (2 K −1 ,j ), . . . , DC t (1 ,j ), DC t (0 ,j )), and
S
t
+
1
(
j
)
[
i
]
=
{
R
t
[
M
-
1
+
j
-
i
]
if
j
<
_
i
W
t
+
1
[
j
-
i
-
1
]
otherwise
,
j
=
0
,
1
,
…
,
M
-
1
,
i
=
0
,
1
,
…
,
K
-
1.
5. The serializer-deserializer as recited in claim 1 wherein said multiplexer is configured to carry out a function MUX P (S[P−1:0],A└2 P −1:0┘) as follows:
MUX 1 ( S[ 0:0 ]A[ 1:0])= S[ 0 ]−A[ 1 ]:A[ 0], and
MUX p+1 ( S[p: 0 ],A[ 2 p+1 −1:0])= S[p]−U 1 :U 0 ,
where
U 1 =MUX p ( S[p− 1:0 ],A└ 2 p+1 −1:2 p ┘), and
U 0 =MUX p ( S[p− 1:0 ],A[ 2 p −1:0]).
6. The serializer-deserializer as recited in claim 1 wherein said serializer-deserializer operates subject to a timing restriction of:
r
>
_
μ
+
ϕ
M
.
7. The serializer-deserializer as recited in claim 1 wherein said analog-to-digital converter, said digital comparator and said multiplexer are pipelined.
8. A method of deserializing data, comprising:
providing a digital output based on a received serial data stream;
employing a digital comparator to compare said digital output to an output table to yield candidate output bits;
employing a digital feedback equalizer to generate said output table based on said candidate output bits; and
selecting output bits from among said candidate output bits to form a discrete bit sequence.
9. The method as recited in claim 8 wherein said providing includes:
comparing a voltage of said serial data stream to various analog reference voltages to generate an output;
deserializing said output; and
compacting said output.
10. The method as recited in claim 8 wherein said candidate output bits are generated in accordance with DC t (i,j)=(ADC t (j)>EQT(i)), i=0, . . . , 2 K −1, j=0, . . . , M−1.
11. The method as recited in claim 8 wherein said employing said digital feedback equalizer comprises carrying out the following functions:
R 0 =0,
W t+1 [j ]=MUX K ( S t+1 ( j ), A t+1 ( j )), and
R t+1 =W,
where
A t +1( j )=(DC t (2 K −1 ,j ), . . . , DC t (1 ,j ), DC t (0 ,j )), and
S
t
+
1
(
j
)
[
i
]
=
{
R
t
[
M
-
1
+
j
-
i
]
if
j
<
_
i
W
t
+
1
[
j
-
i
-
1
]
otherwise
,
j
=
0
,
1
,
…
,
M
-
1
,
i
=
0
,
1
,
…
,
K
-
1.
12. The method as recited in claim 8 wherein said selecting comprises carrying out a function MUX P (S[P−1:0],A└2 P −1:0┘) as follows:
MUX 1 ( S[ 0:0 ]A[ 1:0])= S[ 0 ]−A[ 1 ]:A[ 0], and
MUX p+1 ( S[p: 0 ],A[ 2 p+1 −1:0])= S[p]−U 1 :U 0 ,
where
U 1 =MUX p ( S[p− 1:0 ],A└ 2 p+1 −1:2 p ┘), and
U 0 =MUX p ( S[p− 1:0 ],A[ 2 p −1:0]).
13. The method as recited in claim 8 wherein said method is carried out subject to a timing restriction of:
r
>
_
μ
+
ϕ
M
.
14. The method as recited in claim 8 wherein said providing, said employing said digital comparator and said selecting are carried out in a pipeline.
15. A serializer-deserializer, comprising:
an analog-to-digital converter configured to receive a serial data stream and provide a digital output based thereon and including:
an analog comparator matrix configured to compare a voltage of said serial data stream to various analog reference voltages,
a deserializer coupled to said analog comparator matrix and configured to deserialize an output thereof, and
a compactor coupled to said deserializer and configured to compact an output thereof;
a digital comparator pipelined with said analog-to-digital converter and configured to compare said digital output to an output table to yield candidate output bits;
a digital feedback equalizer coupled to said digital comparator and configured to generate said output table based on said candidate output bits; and
a multiplexer pipelined with said digital comparator and configured to select output bits from among said candidate output bits to form a discrete bit sequence.
16. The serializer-deserializer as recited in claim 15 wherein said candidate output bits are generated in accordance with DC t (i,j)=(ADC t (j)>EQT(i)), i=0, . . . , 2 K −1, j=0, . . . , M−1.
17. The serializer-deserializer as recited in claim 15 wherein said digital feedback equalizer is configured to carry out the following functions:
R 0 =0,
W t+1 [j ]=MUX K ( S t+1 ( j ), A t+1 ( j )), and
R t+1 =W,
where
A t +1( j )=(DC t (2 K −1 ,j ), . . . , DC t (1 ,j ), DC t (0 ,j )), and
S
t
+
1
(
j
)
[
i
]
=
{
R
t
[
M
-
1
+
j
-
i
]
if
j
<
_
i
W
t
+
1
[
j
-
i
-
1
]
otherwise
,
j
=
0
,
1
,
…
,
M
-
1
,
i
=
0
,
1
,
…
,
K
-
1.
18. The serializer-deserializer as recited in claim 15 wherein said multiplexer is configured to carry out a function MUX P (S[P−1:0],A└2 P −1:0┘) as follows:
MUX 1 ( S[ 0:0 ]A[ 1:0])= S[ 0 ]−A[ 1]:A[0], and
MUX p+1 ( S[p: 0 ],A[ 2 p+1 −1:0])= S[p]−U 1 :U 0 ,
where
U 1 =MUX p ( S[p− 1:0 ],A└ 2 p+1 −1:2 p ┘), and
U 0 =MUX p ( S[p− 1:0 ],A[ 2 p −1:0]).
19. The serializer-deserializer as recited in claim 15 wherein said serializer-deserializer operates subject to a timing restriction of:
r
>
_
μ
+
ϕ
M
.