10 MHz Reference Frequency Adjustment

This adjustment should be performed only after the ESA has been allowed to warm up  with the ESA in internal reference mode and in a 20° to 30° C environment during the entire warmup period. The warmup time depends upon the type of frequency reference installed and whether or not the analyzer has Opt 1D5. The 10 MHz reference output is connected to the frequency counter's Channel A input. A cesium beam frequency standard, or some other 10 MHz "house standard" provides the frequency reference for the frequency counter.

If the ESA is equipped with an OCXO, the ESA's coarse timebase DAC is adjusted to yield a frequency counter reading of 10 MHz ±0.1 Hz. Otherwise, the coarse timebase DAC is adjusted for the closest value to 10 MHz. The status of the frequency reference PLL is checked at each setting of the coarse timebase DAC to ensure that it is locked.

The fine timebase DAC is adjusted to yield a frequency counter reading of 10 MHz ± 0.01 Hz if the OCXO is installed or 10 MHz ± 5 Hz if the VCXO is installed. If the analyzer has a OCXO, but does not have Opt 1D5, the tolerance is ± 1 Hz.

The final reference frequency and the values of the coarse and the fine timebase DAC setting are reported

Required Equipment

Instrument Recommended Model For ESA Models Frequency Counter 1 53230A All  Frequency Standard 1 Microsemi 5071A-C002 All  Cable, BNC (2 required) 8120-2582 All  Connection Setups