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- Transition time shift (bit
shift) and amplitude
analysis
- Various defect detectors
for simultaneous analysis of bit shift, missing pulses,
super pulses, and thermal asperities
- Multi-threshold amplitude
analysis at positive and negative signal peaks
- 24 detectors can run
in parallel with different settings/thresholds
- Time shift (bit shift) analysis
by zero-crossing detection for perpendicular recording
- High sampling rate
for precise reconstruction of read-back signal
- High resolution of
detection thresholds
- Real-time digital processing
for high throughput
- 3D presentation
of media defects
- Field upgradeable
processing algorithms
Introduction
D5000 Signal Analyzer opens
new possibilities for media scanning. The analyzer can measure
the amplitude defects (such as missing pulses, super pulses,
and thermal asperities), and the time defects (such as transition
shift). Up to 24 defect detectors can run
simultaneously, with different settings. The high-resolution
thresholds of the defect detectors and multi-threshold amplitude
analysis allow the digital media scanner to generate three-dimensional
map of the defects.
Scanning Algorithm
The typical signal used for media scanning
is an HF pattern. This signal is read back as a high-frequency
sine-wave signal. The read-back signal, digitized with high
oversampling, controls digital PLL, which is running on frequency
two times higher than the read-back signal. The phase of the
PLL signal is adjusted such a way that each sample presents
the positive and negative peaks of the read-back signal. The
value of these samples allows you to analyze the amplitude
defects on media. The position of zero-crossings of the read-back
signal with respect to the PLL clocks (in case of perpendicular
recording) presents a time shift (bit shift). The distribution
of the zero-crossings is analyzed and qualified with respect
to a detection window.
The scanning algorithm is implemented within
the DP5000 Digital Processor. This algorithm can be updated,
when you install a new revision of WITE32.
The DP5000 processor has the throughput high
enough to process the signal from media without any delay,
and then transfer all detected errors to the computer with
high speed. High sampling rate and analog bandwidth allows
D5000 Signal Analyzer to process a sine-wave signal with frequency
up to 1.25GHz.
Table 1 shows the defects,
which can be detected with the D5000 Digital Media Scanning.
Table 1: Samples
of Detected Media Defects
Figure 1 shows the disk
area with a defect in the coordinates of track numbers and
an angular head position with respect to the index. Different
color shades correspond to different depth of the defect.
Figure 1: Amplitude
Defects Detected on Media
The D5000 Digital Media Scanning includes 3D Viewer, which
generates the three-dimensional map of a found defect. Figure
2 shows such map created for the zoomed-in area of
the amplitude defect from Figure 1.
Figure 2: 3D Map of Amplitude Defect
Figure 3 shows the time-shift
distribution (bit-shift plot) of the scan area.
Figure 3: Bit-shift
Plot
D5000 Digital
Media Scanning Requirements
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Guzik D5000 Signal Analyzer
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Guzik RWA-2000 series
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Guzik V2002 or Canon spinstand
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WITE32 Revision 3.40 or later
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D5000 Digital Media Scanning license.
Please contact sales@guzik.com
to obtain a quotation for the license.
Specifications are
subject to change without notice
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