Chapter 2 45
Making Adjustments
3. 10 MHz Reference
Procedure
Note that to properly adjust the time base, a frequency standard with a
better time base accuracy than that of the analyzer is required.
1. Connect the equipment as shown in Figure 2-6.
2. Set the microwave frequency counter controls as follows:
50 Ω/1 MΩ...........................................50Ω Impedance
10 Hz–500 MHz/500 MHz–18 GHz ...10Hz–500MHz
SAMPLE RATE .......................................... Midrange
FREQUENCY STANDARD ................... EXTERNAL
3. Press the following analyzer keys.
PRESET
FREQUENCY, −2001, Hz
CAL, More 1 of 4, More 2 of 4, More 3 of 4
SERVICE CAL, CAL TIMEBASE
4. A number will be displayed in the active function block of the
analyzer display. This is the setting of the DAC (0 to 255) which
controls the frequency of the internal time base. Use the knob or
keyboard to change the DAC setting until the frequency counter
reads 300 MHz ±75 Hz (±0.25 ppm).
5. Once the time base has been adjusted for minimum deviation from
300 MHz, press
CAL, CAL STORE. The new DAC number is now
stored in nonvolatile memory.
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