Tektronix SPG8000 Technical Reference page 54

Performance verification
LTC input gain and
impedance test
40
Genlock input gain.
6. Press the down (▼) arrow button until you see GENLOCK INPUT in the
Diagnostics menu.
7. Connect a 75 Ω terminator on the REF LOOP input on the SPG8000 under
test.
8. Subtract the Min level from the Max level and compare the result to the limits
in the test record. Record the Gain, Min, and Max values in the Genlock
input gain test record.
9. Press the BACK button to exit the menu.
Perform the following procedure to check that the LTC input gain and impedance
are functioning properly. This test is divided into three parts: the first part checks
the LTC positive input open circuit loop back; the second part checks the LTC
negative input open circuit loop back; the third part checks the LTC positive
and negative terminated inputs loop back gain. This test should be performed in
factory mode. (See page 19, Set SPG8000 to Factory Mode.)
LTC positive input open circuit loop back.
1. If you have just finished the previous procedure, press the LTC button until
LTC 1 appears in the menu.
2. Press the up (▲) arrow button until OUTPUT LEVEL appears in the menu.
3. Press the right (►) arrow button until the level shows 5.0 Volt, and then press
the ENTER button.
4. Press the down (▼) arrow button until LTC1 LOOPBACK appears in the
menu.
5. Press the right arrow button (►) until Enable appears in the menu, and then
press the ENTER button.
6. View the diagnostics as follows:
a. Press the SYSTEM button.
b. Press the up (▲) arrow button until DIAGNOSTICS appears in the
menu, and then press the ENTER button.
c. Press the up (▲) or down (▼) arrow buttons until LTC POS INPUT
appears.
7. Record the Min and Max levels in LTC Positive input open circuit loop back
in the test record.
8. Subtract the Min level from the Max level and record the result in LTC
positive open circuit loop back gain in the test record.
SPG8000 Specifications and Performance Verification