TB 9-6625-2134-24
b. Adjustments. No adjustments can be made.
21. Frequency Drift
a. Performance Check
NOTE
This measurement and residual FM are dependent on oscillator
stability. Therefore, the instrument must have the specified
warm-up period and remain at a stable ambient temperature
before checking. A restabilization time of 10 minutes per GHz
of frequency change after the center frequency is returned
must be allowed for instruments that do not have phaselock
option 03.
(1) Position controls as listed in (a) through (f) below:
(a) VERTICAL DISPLAY control to 10 dB/DIV.
(b) REFERENCE LEVEL control to -20 dBm.
(c) FREQUENCY RANGE pushbutton to 0-1.8 GHz.
(d) FREQUENCY SPAN/DIV control to 10 MHz.
(e) TIME/DIV switch to AUTO.
(f) AUTO RESOLUTION control to on.
(2) Connect CAL OUT to RF INPUT, using cable and service kit.
(3) Reduce FREQUENCY SPAN/DIV control to 1 MHz/DIV and press DEGAUSS
pushbutton.
(4) Adjust REFERENCE LEVEL for signal amplitude of 7 divisions. Decrease
FREQUENCY SPAN/DIV control to 50 kHz, keeping the signal centered as necessary
with FREQUENCY control.
(5) Option 02 only: Press DIGITAL STORAGE VIEW A, DIGITAL STORAGE
MAX HOLD, and DIGITAL STORAGE SAVE A pushbuttons to on.
(6) Observe crt for frequency drift. On TIs without option 03, frequency drift will
not exceed 200 kHz after 1 hour. On TIs with option 03, SN B039999 and below, frequency
drift will not exceed 25 kHz after 1 hour. On TIs with option 03, SN B040000 and above,
frequency drift will not exceed 15 kHz after 10 minutes. Drive will appear as the width of
response less resolution bandwidth (fig. 32).
NOTE
Typical display of drift measurement without phaselock
showing width of marker stored with MAX HOLD and
beginning display of marker saved in A.