Tektronix 071-0590-00 user manual Key several times to setup the analyzer for totalize

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Tutorial

B.Locate the controls in the OUTPUT box of the Generator. Adjust the Data amplitude and offset as follows:

Caution: Adjust only the DATA signal. Do not change the CLOCK signal.

Set this parameter	…to this value	…using this procedure.
DATA amplitude.	0.50 volts	Press the DATA key. The LED within the switch
		should be lit.
		Press AMPLITUDE up/down keys until data
		amplitude is set to 0.50V.
DATA baseline offset	-0.25 volts	Press BASELINE OFFSET up/down keys until
		data baseline offset is set to -0.25V.

If you examined this output data signal (voltage vs. time) on a scope, it would look similar to:

+0.25
+0.00
-0.25
Voltage
-0.50	time →

← Maximum Level

−

0.5 V ← Optimum Threshold

−amplitude

		⏐	↓	← Minimum Level
−		⏐
-0.25 V	best value to use for THIS data
data offset
	threshold is ~0.00 Vdc + 0.05 Vdc

You will now be manually adjusting the data input threshold for the GB1400 Analyzer. Locate the controls in the PATTERN box of the Analyzer. Make sure

F2 and F3 are turned OFF. These switches are used when adjusting CLOCK or REF DATA input parameters.

C.Locate the controls in the INPUT box of the Analyzer. Verify that the Analyzer THRESH LED is turnedO N. This allows manual adjustment of the DATA Input threshold. The threshold for the selected signal (clock or data) is shown on the bottom line of the Analyzer’s alpha-numeric status display. Using the INPUT UP/DOWN keys, adjust this threshold and confirm the following actions:

Note: The BER display on the Analyzer can be set to totalize, window, or test modes. When in the totalize mode, a small ∞ (infinity) symbol will be displayed before the BER error rate. Use totalize mode for this tutorial exercise. Press the

key several times to setup the analyzer for totalize

GB1400 User Manual 2-35