Agilent Technologies 8504B, User Manual

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FINAL TRIM SIZE : 7.5 in x 9.0 in
P erforming Measurements
Setting the Measurement Range
Horizontal scale
readings depend upon
refractive index
The precision reectometer's maximum measurement span depends upon the
refractive index of the light path. The default horizontal scale corresponds to
a refractive index (n) of 1. (This is the value for light in air , and it gives the
precision reectometer's maximum range of 400 mm.) Entering a dierent
refractive index, using the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
REFRACTIVE INDEX (n) softkey , changes the
horizontal scale but not the position of responses on the display .
Refraction index = 1.
Refraction index = 1.44.
The precision reectometer is designed so that if the lengths of the
REFERENCE EXTENSION and TEST PORT cables are equal, the rst response
appears approximately one division to the right of the display's left edge in
a 400 mm span. (This response is reected from the end of theTEST PORT
cable .) F or every 28 millimeters that the TEST PORT cable is longer than the
REFERENCE EXTENSION cable , this response moves one division towards the
right. Twenty-eight millimeters of actual ber length has an equivalent air
length of 40 mm.
Return to full span with
the press of a key
Y ou can return the instrument to the full 400 nm span at any time by
pressing 4 MENU 5
NNNNNNNNNNNNNNNNNNNNNNNNNNNNN
FULL SPAN . Next to the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNN
FULL SPAN key , you'll nd the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
ZERO SPAN on OFF softkey . This softkey make the precision reectometer
into what is essentially a programmable delay line . It sets the center setting
to the former start value and stops the sweep (mirror movement).
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