New Frequency Standard and Time Interval Generator

I HE problem of measuring frequencies and of standardizing frequency-measuring equipment confronts nearly every present-day electronics and communications laboratory. It is common practice to solve this problem with the use of a frequency standard. In the past primary standards—those checked against time—and secondary standards —those checked against a primary standard—have both been used relatively widely. However, the reliability and convenience of standardizing with the Bureau of Standards transmissions from Station WWV have resulted in the almost exclusive current use of secondary frequency standards as the principal laboratory source of accurate frequencies. It is desirable that the secondary standard in use be as versatile as possible in addition to being accurate and relatively inexpensive.

/ Figure I. Mode! 100D Loa f requency Standard.

^HE Model 1001) Secondary Frequency Standard shown in Figure 1 lias been developed with the above general requirements in mind. This standard generates five sinusoidal standard frequencies: 100 kc, 10 kc, I kc. 100 cps, and 10 cps. The equipment also generates rectangular waves at all the above repetition rates except 100 kc. Harmonics as high as five megacycles can be obtained from these rectangular waves for measurement purposes. In addition to the sinusoidal and rectangular voltages, the standard generates marker pips at KH)-microsecond intervals. A self-contained oscilloscope

COPÏBI5H7 HEWLETT PACKARO CO.

Figure 2. Block Diagram of 100D Circuit,

further con tribu tes to the convenience with which external frequencies can be measured.

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