CHAPTER FIVE
g.
Reinstall the dust cap screw on the side of oscillator.
5.5.2 FREQUENCY OUTPUT AMPLITUDE ADJUSTMENT (Routine Adjustment)
a.
Connect the Frequency Output BNC Connector, J5, to an Oscilloscope
terminating it with 50 Ohms and observe a 10 MHz Sine Wave. See Chapter
Three, Section 3.10.
b.
Adjust the output for an amplitude of 2.8 +0.2 Volts Peak-to-Peak into a 50 Ohm
load using Potentiometer R184, labeled “OSC LEVEL”.
5.5.3 CODE OUTPUT ADJUSTMENTS (Routine Adjustments)
Following are the adjustments for the Modulated Serial Time Code output:
a.
Connect the rear panel BNC connector J10, the IRIG B Modulated Serial Time
Code Output, to an oscilloscope terminated with 50 Ohms.
b.
Phase Adjustment: While observing the code output on an oscilloscope, adjust
R100, labeled “PHASE” for minimum discontinuity at the modulation points of
the code. This is the point where the sine wave goes from a “Mark” amplitude to a
“Space” near the zero crossing point.
c.
Amplitude Adjustment: While observing the code output on an oscilloscope,
adjust R101, labeled “LEVEL”, for a 3 +0.2 Volts peak-to-peak or desired
amplitude.
d.
Modulation Ratio Adjustment: While observing the code output, adjust R86,
labeled “RATIO” for a 3:1 or other desired ratio of the “Mark” amplitude to the
“Space” amplitude.
5.5.4 LCD CONTRAST ADJUSTMENT (Routine Adjustment)
If the LCD will be consistently viewed from a higher or lower angle than normal, R9 (Near
connector J103) on the STCG, may be adjusted to improve contrast. Keep in mind that
improving the contrast from one angle may make it worse from another. Seek an optimum
compromise.
5-10
TM7000 TymMachine TCG/T (Rev D)
Symmetricom, Inc.