Appeal No. 97-1167 Page 3
Application No. 08/475,062
BACKGROUND
The invention at issue in this appeal relates to digital
magnetic recording. It is an apparatus for recording (i.e.,
writing) data on and reproducing (i.e., reading) data from a
magnetic disk. More specifically, the apparatus includes a
distortion detector, a measuring circuit, and a bias control
circuit. The distortion detector measures a second harmonic
distortion (SHD) of a reproduced signal; the measuring circuit
measures the signal-to-noise (S/N) ratio of the reproduced
signal. The bias control circuit controls the bias current in
the reproducing head to maintain the SHD at or below -25 dB
while maximizing the S/N ratio. By maximizing the S/N ratio
while maintaining the SHD at or below this level, the
apparatus minimizes the bit error rate of the data it
reproduces.
Claim 3, which is representative for our purposes,
follows:
3. A digital magnetic reproducing apparatus
comprising a reproducing head to reproduce data from
a magnetic recording medium; an equalizer for
shaping, by a partial response method, a waveform of
the reproduced signal output from said reproducing
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007