Abstract: A preamplifier system is provided for connection through an interconnect to a read head. The interconnect has a characteristic impedance associated therewith. The preamplifier system includes an amplifier circuit having an input for connection to the interconnect. The amplifier circuit amplifies an input signal carried from the read head through the interconnect, yielding an amplified input output signal. A feedback resistance is connected between the amplified output signal and the input of the amplifier circuit. The feedback resistance has a value selected to provide an effective input impedance of the preamplifier system to match the characteristic impedance of the interconnect.

Abstract: A plurality of data bits are magnetically recorded on a medium (such as a magnetic disk in a disk drive system) by creating a write bubble region encroaching on the medium. The write bubble region has a magnetic polarity that is reversed in a pattern that corresponds to the values of the data bits being recorded on the medium. The timing of the reversing of the magnetic polarity of the write bubble region is adjusted by a precompensation system to ensure that the recorded data bits are evenly spaced on the medium. The timing adjustment is made by the precompensation system based on a state of at least one data bit previously recorded on the medium and on a state of at least one data bit to be subsequently recorded on the medium.

Abstract: A pulse-mode data writing protocol is disclosed which reduces the time required to implement a transition in the direction of magnetization of a recording medium, and which reduces the total power required to encode a given data sequence. After a magnetic transition is encoded on the medium by generating a write current pulse through the write head, the write current through the recording head is reduced, thereby utilizing the spatial extent of the write bubble to encode the lack of a transition on the medium. Alternate configurations are disclosed for various scenarios of write bubble size versus maximum cell size, all utilizing the principle of the invention.

Abstract: A plurality of data bits are magnetically recorded on a medium (such as a magnetic disk in a disk drive system) by creating a write bubble region encroaching on the medium. The write bubble region has a magnetic polarity that is reversed in a pattern that corresponds to the values of the data bits being recorded on the medium. The timing of the reversing of the magnetic polarity of the write bubble region is adjusted by a precompensation system to ensure that the recorded data bits are evenly spaced on the medium. The timing adjustment is made by the precompensation system based on a state of at least one data bit previously recorded on the medium and on a state of at least one data bit to be subsequently recorded on the medium.

Abstract: A preamplifier system is provided for connection through an interconnect to a read head. The interconnect has a characteristic impedance associated therewith. The preamplifier system includes an amplifier circuit having an input for connection to the interconnect. The amplifier circuit amplifies an input signal carried from the read head through the interconnect, yielding an amplified input output signal. A feedback resistance is connected between the amplified output signal and the input of the amplifier circuit. The feedback resistance has a value selected to provide an effective input impedance of the preamplifier system to match the characteristic impedance of the interconnect.

Abstract: Echo cancellation is provided in a disk drive circuit having a transducing head connected to a preamplifier circuit by an electrical interconnect with a first time delay, a first interface between the preamplifier and the electrical interconnect having a first reflection coefficient and a second interface between the transducing head and the electrical interconnect having a second reflection coefficient. The echo cancellation technique delays a preamplifier output signal with a second time delay, the second time delay being double the first time delay. The preamplifier output signal is also filtered so as to simulate the effects of the first and second reflection coefficients. The delayed and filtered signal is then subtracted from the preamplifier output signal, thereby removing echo content from the signal.