1. A method for differential-mode processing of an incident voltage relative to a reference voltage and comprising:
a voltagecurrent conversion delivering two opposing currents corresponding to a difference between the incident voltage and the reference voltage;
an amplification of the two opposing currents with a gain selected from within a range of gains, and an elimination of a DC component of the two amplified opposing currents, so as to obtain two resulting currents; and
a currentvoltage conversion of the resulting currents into a differential output voltage centered around a common-mode voltage.
2. The method according to claim 1, wherein the elimination of the DC component of the two amplified opposing currents comprises a division by two of an amplitude of the two amplified opposing currents, and subtractions between the divided amplified signals, so as to obtain the two resulting currents.
3. A method for processing a voltage signal from a photodetector comprising:
generating two opposing currents based upon a difference between the voltage signal and a reference voltage signal;
amplifying the two opposing currents and eliminating a DC component of the two amplified opposing currents to obtain two resulting currents; and
converting the resulting currents into a differential output voltage centered around a commonmode voltage.
4. The method according to claim 3, wherein eliminating the DC component of the two amplified opposing currents comprises dividing an amplitude of the two amplified opposing currents, and subtracting the divided amplified signals, to obtain the two resulting currents.
5. The method according to claim 3, wherein amplifying the two opposing currents comprises amplifying with a gain selected from within a range of gains.
6. A device for differential-mode processing an incident voltage relative to a reference voltage, the device comprising:
a voltagecurrent conversion block having a differential input to receive the incident voltage at a first input and the reference voltage at a second input, and to deliver at an output two opposing currents corresponding to the difference between the incident voltage and the reference voltage;
a current amplification block receiving the two opposing currents output from the voltagecurrent conversion block and outputting two amplified opposing currents centered around zero; and
a currentvoltage conversion block comprising an operational amplifier with differential transimpedance supplied with a common-mode voltage, receiving the two amplified opposing currents output from the amplification block and generating two calibrated opposing voltages that are centered around the common-mode voltage.
7. The device according to claim 6, wherein the current amplification block comprises a gain module and a current subtraction module, the subtraction module receiving the two amplified opposing currents output having an amplitude divided by two from the gain module, and outputting two currents in phase opposition, centered around zero and with no DC component.
8. An optical signal reader system comprising:
a photodetector generating an incident voltage signal; and
a device for processing the incident voltage signal relative to a reference voltage, the device comprising:
a voltagecurrent conversion block having a differential input to receive the incident voltage and the reference voltage, and to deliver two opposing currents corresponding to the difference between the incident voltage and the reference voltage,
a current amplification block receiving the two opposing currents output from the voltagecurrent conversion block and outputting two amplified opposing currents centered around zero, and
a currentvoltage conversion block comprising an operational amplifier with differential transimpedance supplied with a commonmode voltage, receiving the two amplified opposing currents output from the amplification block and generating two calibrated opposing voltages that are centered around the common-mode voltage.
9. The system according to claim 8, wherein the current amplification block comprises a gain module and a current subtraction module, the subtraction module receiving the two amplified opposing currents output having an amplitude divided by two from the gain module, and outputting two currents in phase opposition, centered around zero and with no DC component.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A spin valve (SV) sensor having first and second passive regions and a central track width region transversely disposed between said first and second passive regions, said SV sensor comprising:
a pinned layer;
a ferromagnetic free layer;
a spacer layer sandwiched between said pinned layer and said free layer;
a ferromagnetic bias layer in said first and second passive regions;
an antiparallel coupling layer sandwiched between said free layer and said ferromagnetic bias layer for providing strong antiparallel coupling between said bias layer and said free layer in the first and second passive regions; and
an antiferromagnetic (AFM) layer adjacent to said ferromagnetic bias layer, said AFM layer exchange coupled to the ferromagnetic bias layer to provide a pinning field to the bias layer;
wherein said pinning field is directed in a canted direction intermediate between a direction parallel to an air bearing surface and a direction perpendicular to the air bearing surface.
2. The SV sensor as recited in claim 1 wherein said AFM layer is made of Pt\u2014Mn, said AFM layer having a thickness in the range of 30-100 \u212b.
3. The SV sensor as recited in claim 1 wherein said AFM layer is chosen from a group of materials consisting of Pt\u2014Mn, Ir\u2014Mn and Ni\u2014Mn.
4. The SV sensor as recited in claim 1 wherein said AFM layer has a thickness greater than zero but less than the thickness needed to provide a saturation value of said pinning field to the bias layer.
5. The SV sensor as recited in claim 1 wherein said bias layer has a thickness greater than the thickness of said free layer.
6. A disk drive system comprising:
a magnetic recording disk;
a magnetic read head for sensing magnetically recorded recorded data on the magnetic recording disk, said magnetic read head comprising:
a spin valve (SV) sensor, the SV sensor being sandwiched between first and second read gap layers, the SV sensor having first and second passive regions and a central track width region transversely disposed between said first and second passive regions, said SV sensor comprising:
a pinned layer;
a ferromagnetic free layer;
a spacer layer sandwiched between said pinned layer and said free layer;
a ferromagnetic bias layer in said first and second passive regions;
an antiparallel coupled layer sandwiched between said free layer and said ferromagnetic bias layer for providing strong antiparallel coupling between said bias layer and said free layer in the first and second passive regions;
an antiferromagnetic (AFM) layer adjacent to said ferromagnetic bias layer, said AFM layer exchange coupled to the ferromagnetic bias layer to provide a pinning field to the bias layer;
wherein said pinning field is directed in a canted direction intermediate between a direction parallel to an air bearing surface and a direction perpendicular to the air bearing surface; and
an actuator for moving said magnetic read head across the magnetic disk so that the read head may access different regions of the magnetic recording disk; and
a recording channel coupled electrically to the SV sensor of the read head for detecting changes in resistance of the SV sensor in response to magnetic fields from the magnetically recorded data.
7. The disk drive system as recited in claim 6 wherein said AFM layer is made of Pt\u2014Mn, said AFM layer having a thickness in the range of 30-100 \u212b.
8. The disk drive system as recited in claim 6 wherein said AFM layer is chosen from a group of materials consisting of Pt\u2014Mn, Ir\u2014Mn and Ni\u2014Mn.
9. The disk drive system as recited in claim 6 wherein said AFM layer has a thickness greater than zero but less than the thickness needed to provide a saturation value of said pinning field to the bias layer.
10. The disk drive system as recited in claim 6 wherein said bias layer has a thickness greater than the thickness of said free layer.