Gentec-eo MACH 6 Manuel d'utilisateur télécharger pdf (Page 14)

Mach 6 User’s Manual Revision 2.1 14

With internal triggering, if the pulse is below the trigger level, no trigger will occur, but

the period timer will still be running. This means that the period will be longer between

the pulses adjacent to the missing pulses. The applications software examines the pulse

data for this condition and records the time stamps where the period is discontinuous.

From the continuous period data, the true period can be found and used to count how

many pulses were missing in the discontinuities.

The % Frequency Stability Threshold setting determines how much time stamp mismatch

is allowed when computing the true frequency.

Wavelength

Sets the wavelength of the laser in use. Since the sensor responsivity varies with

wavelength, turning Wavelength Compensation on with the wavelength set to any value

other than the calibration wavelength may cause a rescale of the available ranges. If this

occurs, the instrument will set itself to the same currently set range if it is still available.

If it is not, the instrument will set itself to the next available range.

Aperture Area

The sensor or user aperture area in cm

Attenuation Factor

This is used to compensate the data for the use of an external optic, such as a beam

splitter. If the external optic is only presenting 10% of the beam to the sensor, then enter

0.1 for the factor. The data will be scaled by 1 / Attenuation Factor so that it represents

the energy of the beam before the optic.

If this causes the data values to exceed the range, then the strip charts in the various

displays will need to be set to auto scale before the data will be visible.

Note: This parameter must be set before reading the Pulse Data.

Sigma for Standard Deviation

The number, z, used in the standard deviation value. If a data distribution is

approximately normal then about 68% of the values are within 1 standard deviation of the

mean, about 95% of the values are within two standard deviations and about 99.7% lie

within 3 standard deviations.

For various values of z, the percentage of values expected to lie in the symmetric

confidence interval (-zs,zs) are as follows:

s percentage

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 47 48

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Gentec-eo MACH 6 Manuel d'utilisateur Page 14