Tektronix SDA601, Руководство по обслуживанию

Страница: 87 / 132

Maintenance
SDA 601 Serial Digital Analyzer 5- 7
Figure 5- 1: Numeric SLM Data
The top line contains—in A/D units, or “LSBs”—the internal instrument
temperature, the corrected signal level, and the uncorrected (“raw”)
signal level. The second line contains a numeric readout of the corrected
signal strength in dB. This value corresponds to the LSBs reported in the
top line, and to the normal bar-graph display of the SLM.
To exit the numeric SLM display mode and replace the display with the
normal SLM bar graph, press the
SLM (A) key.
4. NVRAM/TIC Dgs.
The NVRAM/Timer (Touch Memory
T
) microprocessor in the SDA601 is
contained in a button-shaped stainless steel can with its own lithium battery.
It is known widely as the “time in a can”—or “TIC.”
a. Get TIC Serial — Press
ENTER
to discover the unique serial number of
the TIC. This is an easy way to verify the presence and function of the
TIC NVRAM.
b. Get TIC Time — Press ENTER to read the number of seconds since 00:00
hours, January 1, 1970; the display will update each second and verify
the function of the TIC clock.
c. Read TIC Memory — Enter any TIC memory address (0–255) to read
the contents and verify that the instrument can retrieve data from TIC
NVRAM. To read the contents of memory location 159, for example,
press
1 (L) , 5 (R) , and 9 (X) , then press ENTER .
Figure 5- 2: The SDA Number Keys