B. Operating Performance Checks
5. Measure the pulse frequency coming off the front panel cable connector. The averaged
pulse frequency should be 250.0
±
0.2 kHz for Short, 50.00
±
0.04 kHz for Medium, and
12.50
±
0.02 kHz for Long.
6. Repeat pulse width check for Medium and Long settings.
B.4.7
Sequential Sampling Rate Check
The sequential sampling rate is the reciprocal of the pulse repetition time.
B.4.8
Vertical Scale Check
Twist the
VERTICAL SCALE
knob clockwise. Vertical scale should drop to 0.5 millirho/div
and the trace should expand accordingly.
B.4.9
Vertical Accuracy Check (millirho)
1. Attach an open to the CT100B.
2. Position a cursor on the trace so that it is well after the open.
3. The vertical measurement should be between 940 millirho and 1060 millirho.
B.4.10
Vertical Position Check
1. Increase vertical scale to 500m
ρ
/div by turning the
VERTICAL SCALE
knob
counter-clockwise.
2. Use the
VERTICAL POSITION
knob to move the live trace completely above the
horizontal midline of the screen.
3. Use the
VERTICAL POSITION
knob to move the live trace completely below the
horizontal midline of the screen.
A CT100B must succeed at both operations to pass the Vertical Position Check.
B.4.11
Distance Cursor Resolution Check
Distance cursor resolution is a value determined by a constant. It can be measured by counting
distinct locations that a cursor may occupy between two division lines, including one of the
division lines.
B.4.12
Cursor Readout Range Check
In the
Measurement
menu, toggle on
Extra Long Mode
.
Turn the
HORIZONTAL SCALE
knob counter-clockwise until horizontal scale is maximized.
Using the
M-FUNC
button and
M-FUNCTION
knob, set Vp to 1.000.
With the
HORIZONTAL SCALE
knob, position a cursor at the most far right position
possible.
The absolute distance measurement for the cursor is the upper limit for cursor readout range.
This number should be larger than 10,000 m or 33,000 ft.
90
CT100B TDR Cable Analyzers Operator’s Manual
