LC
Series & 9300 Series Disk Drive Software
Packages
The
Disk Drive Measurement and PRML Measurement Packages
utilize IDEMA® test methods and industry standard
PRML measurements to extend the range of
capabilities of the LeCroy LC Series Color DSOs
& 9300 series Digital Oscilloscopes to provide
in-depth analysis of disk drive performance.
Pulse
Width 50
Track Average Amplitude
Resolution
Overwrite
Transition
Shift
Auto-Correlation Signal-to-Noise
Auto Correlation
Local
time between peaks
Local time between troughs
Local time over threshold
And ten others...
Histograms provide bar charts for easy analysis of
measurement results over many events.
DISK DRIVE SOFTWARE
PACKAGES
The Disk Drive Measurement and PRML Measurement
Packages utilize IDEMA® test methods and industry
standard PRML measurements to extend the range of
capabilities of the LeCroy LC Series & 9300
series Digital Oscilloscopes to provide in-depth
analysis of disk drive performance.
Combine the 9354's 500 MHz analog bandwidth (or the
9370's 1 GHz bandwidth), 2 GS/s maximum sample rate,
2 MByte record length per channel (combinable to 8
MBytes), sequence triggering, and Smart Trigger(TM)
operation with these new disk drive analysis
packages any you have the perfect solution to
complete disk drive analysis and testing.
Now you can make your standard disk drive
measurements and PRML measurements with your LeCroy
LC Series & 9300 Series scope and view the
results on screen. Both packages are fully
programmable over GPIB or RS-232.
DISK DRIVE PARAMETERS
PACKAGE
The Disk Drive Measurement package includes
processing functions specified in the International
Disk Drive Equipment and Materials Association (IDEMA®)
test standards document*. These include:
Disk Drive Measurements of
Pulse Width, Track Amplitude, Resolution and
Overwrite
| Name |
Description |
| PW50* |
(see
note 1 below) Pulse Width 50: Provides an
average pulse width, measured at 50% peak
amplitude, of all peak/trough pairs in the
specified waveform. |
| PW50(+) |
Pulse
Width 50 (+): Provides an average pulse width,
measured at 50% peak amplitude, of all peaks
in the specified waveform.
|
| PW50
(-) |
Pulse
Width 50 (-): Provides an average pulse width,
measured at 50% peak amplitude, of all troughs
in the specified waveform. |
| TAA
±* |
(see
note 2 below) Track Average Amplitude:
Provides an average peak-to-peak
amplitude of all Peak/Trough pairs in the
specified waveform. |
| TAA
(+) |
Track
Average Amplitude (+): Provides an average
peak
amplitude of all peaks in the specified
waveform. |
|
TAA
(-) Track Average Amplitude (-): Provides an
average peak amplitude of all troughs in the
specified waveform.
|
| RESOLUTION* |
(see
note 3 below) Specified as
(TAA(F1)/TAA(F2))*100%
Where:
F1 = Low Frequency
F2 = High Frequency
OW*(see note 4 below) Overwrite: Specified as:
10 log (Vr/Vo)
Where: Vr if the residual Vrms of F1 (low
frequency) after F2(high frequency) write
V0 is the Vrms of F1 (low frequency) after F1
write. |
FEATURE ANALYSIS PARAMETERS
Parameters that provide for analysis of amplitude
and timing relationships between features
(peak/trough pairs) of a waveform are also included
in the Disk Drive Measurement Package. Used in
conjunction with the Histogram processing function a
statistical description of the waveform can be
calculated.
| Name |
Description |
| lmax |
local
maximum |
| lmin |
local
minimum |
| lnum |
number
of local peak and trough pairs |
| lpp |
local
peak to peak (lmax - lmin) |
| ltbe |
local
time between events (either peak to trough or
trough to peak) |
| ltbp |
local
time between peaks |
| ltbt |
local
time between troughs |
| ltmn |
local
time at minimum |
| ltmx |
local
time at maximum |
| ltot |
local
time over threshold |
| ltpt |
local
time between peak and trough |
| lttp |
local
time between trough and peak |
| ltut |
local
time under threshold |
|
*As
specified in IDEMA Standards.
1994 Revised Edition
Note 1. Document No. T15-91
Note 2. Document No. T3-91
Note 3. Document No. T4-91
Note 4. Document No. T14-91 |
|
|
|
|
FREQUENCY
DOMAIN PARAMETERS DESCRIPTION
These parameters provide a rapid technique to
extract the amplitude and phase of single
frequencies from complex waveforms. These parameters
are more efficient than using an FFT if the
frequencies of interest are known.
STATISTICAL PARAMETERS
FEATURES DESCRIPTION
These parameters are used in conjunction with
histograms to allow for easy interpretation of the
results.
Histograms:
Any waveform parameter may be histogrammed. The
histogram function produces a waveform with the
vertical axis in units of "Events" and the
horizontal axis in parameter units (volts,
nanoseconds, ...etc.). The histogram shows the
statistical variation of the selected parameter.
| Name |
Description |
| nbph |
narrow-band
phase in degrees relative to start of waveform |
| nbpw |
narrow-band
power in dBv |
| Low |
minimum
value |
| High |
Maximum
value |
| Range |
High
- Low |
| FWHM |
Full
Width Half Max |
| Maxp |
Maximum
Population is the highest population (vertical
value) in the histogram |
| Average |
Mean
value |
| Sigma |
Standard
deviation |
| Tpop |
Total
Population |
| XAPK |
Provides
the horizontal position of the selected peak |
| Pks |
Provides
the total number of peaks |
| Median |
Provides
the horizontal position of the value which
divides the histogram into two equal
populations |
| Mode |
Provides
the horizontal position of the most frequently
occurring value |
| Percentile |
Provides
the horizontal position of the peak which
separated the histogram such that the
population on its left is a specified
percentage on the total. |
PRML
Measurement Package
PRML
PARAMETERS
PRML (Partial Response Maximum Likelihood) recording
channels provide higher areal densities by allowing
magnetic transitions to be written at closer spacing
than peak detection channels. The following
parameters provide a time domain technique to
measure the time shift and S/N ratio created by this
magnetic writing process.
PRML
MEASUREMENT PACKAGE
Includes the following functions:
Non Linear Transition Shift
Auto Correlated Signal to Noise
Auto Correlation
NLBS non-Linear Bit (or Transition) Shift:
NLBS = -2*r
Where r = auto correlation coefficient @
time delay
ACSN Auto Correlation Signal to Noise Ratio:
ACSN = 10 log (R/1-R)
Where R = correlation coefficient
AutoCorrelation Rx (u) = * fx(t)fx(t-u)dt
|
