Adaptive correction of symmetrical and asymmetrical saturation in magnetic recording devices
View Patent ↗A magnetic recording device includes a preprocessor, an interpolator and a slicer. The preprocessor receives at least n saturated input signals including an n th saturated input signal The preprocessor is configured to process each of the n saturated input signals to produce a corresponding n th output signal. The n output signals include an nm output signal from the n th saturated input signal. The interpolator processes the n th output signal to determine an n th interpolator output. The slicer determines an n th slicer output for the n h output signal. The n th slicer output is at one of three different levels. The preprocessor can receive and process an n + 1 th saturated input signal to produce an n + 1 th output signal that is based on a difference between the n th interpolator output and the level of the n th slicer output.
1. A magnetic recording device for correcting saturated signals, the magnetic recording device comprising:
a preprocessor that receives at least n saturated input signals including an n th saturated input signal, the preprocessor being configured to process the n saturated input signals to produce a corresponding n output signals, the n output signals including an n th output signal from the n th saturated input signal;
an interpolator that processes the n th output signal to determine an n th interpolator output; and
a slicer that determines an n th slicer output for the n th output signal, the n th slicer output being at one of three different levels;
wherein the preprocessor receives and processes an n+1 th saturated input signal to produce a n+1 th output signal that is based on a difference between the n th interpolator output and the level of the n th slicer output.
2. The magnetic recording device of claim 1 wherein the three different levels of the n th slicer output include a positive level, a zero level and a negative level.
3. The magnetic recording device of claim 1 wherein the magnetic recording device corrects both symmetrically and asymmetrically saturated signals.
4. The magnetic recording device of claim 1 wherein the n th output signal is produced using current values of a positive coefficient, a zero coefficient, and a negative coefficient.
5. The magnetic recording device of claim 4 wherein for the n+1 th saturated input signal received by the preprocessor, the current value of one of the positive coefficient, the zero coefficient and the negative coefficient is adjusted depending on level of the n th slicer output.
6. The magnetic recording device of claim 4 wherein the preprocessor produces the n th output signal from the n th saturated input signal according to:
y o =y i +Kpos (y i ) 2 +Kzer if y i >0,
y o =y i +Kneg (y i ) 2 +Kzer otherwise;
and wherein:
y i denotes the n th saturated input signal;
y o denotes the n th output signal;
Kpos denotes the positive coefficient;
Kzer denotes the zero coefficient; and
Kneg denotes the negative coefficient.
7. The magnetic recording device of claim 4 wherein for the n+1 th saturated input signal that is received by the preprocessor:
if the n th slicer output is at the positive level, then the current value of the positive coefficient is adjusted;
if the n th slicer output is at the zero level, then the current value of the zero coefficient is adjusted; and
if the n th slicer output is at the negative level, then the current value of the negative coefficient is adjusted.
8. The magnetic recording device of claim 4 wherein for the n+1 th saturated input signal received by the preprocessor, the value of one of the positive coefficient, the zero coefficient, and the negative coefficient is adjusted according to:
Kpos n+1 =Kpos n −μ a ·(x k {circumflex over (x)} k ) if e,cir x k =+1
Kzer n+1 =Kzer n −μ b ·(x k ) if {circumflex over (x)} k= 0
Kneg n+1 =Kneg n 31 μ a ·(x k −x k ) if {circumflex over (x)} k =−1
and wherein:
Kpos denotes the positive coefficient;
Kzer denotes the zero coefficient;
Kneg denotes the negative coefficient;
x k denotes the n th interpolator output;
{circumflex over (x)} k denotes the n th slicer output; and
μ a and μ b are positive constants.
9. A magnetic recording device for correcting saturated signals, the magnetic recording device comprising:
a preprocessor that receives at least n saturated input signals including an n th saturated input signal, the preprocessor being configured to process the n saturated input signals to produce a corresponding n output signals, the n output signals including an n th output signal from the n th saturated input signal;
an interpolator that processes the n th output signal to determine an n th interpolator output; and
a slicer that determines an n th slicer output for the n th output signal, the n th slicer output being at one of three different levels;
wherein the preprocessor receives and processes an n + 1 th saturated input signal to produce a n+1 th output signal that is based on each of the n th interpolator output that is received by the preprocessor directly from the interpolator, and the level of the n th slicer output.
10. The magnetic recording device of claim 9 wherein the three different levels of the first n th slicer output include a positive level, a zero level and a negative level.
11. The magnetic recording device of claim 9 wherein the magnetic recording device corrects both symmetrically and asymmetrically saturated signals.
12. The magnetic recording device of claim 9 wherein the n th output signal is produced using current values of a positive coefficient, a zero coefficient, and a negative coefficient.
13. The magnetic recording device of claim 12 wherein the preprocessor produces the n th output signal from the n th saturated input signal according to:
y o =y i +Kpos (y i ) 2 +Kzer if y i >0,
y o =y i +Kneg (y i ) 2 Kzer otherwise;
wherein:
y i denotes the n th saturated input signal;
y o denotes the n th output signal;
Kpos denotes the positive coefficient;
Kzer denotes the zero coefficient; and
Kneg denotes the negative coefficient.
14. The magnetic recording device of claim 12 wherein for the n+1 th saturated input signal that is received by the preprocessor:
if the n+ th slicer output is at the positive level, then the current value of the positive coefficient is adjusted;
if the n th slicer output is at the zero level, then the current value of the zero coefficient is adjusted; and
if the n th slicer output is at the negative level, then the current value of the negative coefficient is adjusted.
15. The magnetic recording device of claim 12 wherein for the n+1 th saturated input signal received by the preprocessor, the value of one of the positive coefficient, the zero coefficient, and the negative coefficient is adjusted according to:
Kpos n+1 =Kpos n μ a ·(x k− {circumflex over (x)} k ) if {circumflex over (x)} k =+1
Kzer n+1 =Kzer n −μ b ·(x k ) if {circumflex over (x)} k =0
Kneg n+ =Kneg n μ a· (x k −{circumflex over (x)} k ) if {circumflex over (x)} k=− 1
wherein:
Kpos denotes the positive coefficient;
Kzer denotes the zero coefficient;
Kneg denotes the negative coefficient;
x k denotes the n th interpolator output;
{circumflex over (x)} k denotes the n th slicer output; and
μ a and μ b are positive constants.
16. A magnetic recording device for correcting saturated signals, the magnetic recording device comprising:
a preprocessor that receives at least n saturated input signals including an n th saturated input signal, the preprocessor being configured to process the n saturated input signals to produce a corresponding n output signals, the n output signals including an n th output signal from the n th saturated input signal;
an interpolator that processes the n th output signal to determine an n th interpolator output; and
a slicer that determines an n th slicer output for the n th output signal, the n th slicer output being at one of three different levels;
wherein the preprocessor receives and processes an n+1 th saturated input signal to produce a n+1 th output signal that is based on each of the n th interpolator output and the level of the n th slicer output; and
wherein for the n+1 th saturated input signal received by the preprocessor, the current value of one of the positive coefficient, the zero coefficient and the negative coefficient is adjusted depending on the level of the n th slicer output.