Type Ab Frequency Standard

Emergency power equipment, which assures continuity of service despite interruption of normal power service, is now incorporated in a new assembly of standard-frequency equipment, the Type 1120-AB Frequency Standard. The individual standard-frequency instruments, which have been described previously,1 are:

Type 1113-A Standard-Frequency

Oscillator Type 1114-A Frequency Divider Type 1103-B Swcroxometeii® time comparator The additional units, which provideemer-gency power, are:

Type 1116-B Emergency" Power Supply

Type 1268-A Automatic Battery

Charger Type 1268-P1 Battery' Drawer Type 1268-9602 Battery The entire assembly is housed in a floor-type cabinet rack, as shown in Figure 1.

Standard-Frequency Oscillator

The performance of the Type 1113-A Standard-Frequency Oscillator has amply justified the original evaluations1 of its over-all stability. The one-year drift record of a typical unit is shown in Figure 2. Note that the drift rate at the end of a year has diminished to less than one part in 10fl per month, or better than .3 parts in 10u per day.

1R. W. Frank, F. F). Lewis, and IT. P. Stratemeyer, "The New GR Frequency Standard," General Radio Experimenter, 35, 4, April 1961.

Figure 1. View of the Type 1120-AB Frequency Standard.

Of particular interest is the spectrum plot of Figure 3, which indicates a high degree of short-term stability, that is,

Figure 2. Typical long-term frequency drift of Type 1 1 1 3-A Standard-Frequency Oscillator.

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