A frequency standard for a microwave spectrometer

Details of the frequency standard being used in Saha Institute since June 1966 are presented. The 100 KHz output of a G.R. 1100 AP `primary¿ standard is multiplied to produce several hundred milliwatts at 50 MHz and 500 MHz. These are applied to a K-band harmonic generator and produce marker frequencies spaced by 50 MHz in the 18¿16 GHZ band. The microwave absorption line is compared to and interpolated with these markers by a communication receiver. The accuracy and stability of these markers is the same as that of the standard GR 1100 AP, which is a few parts in a billion. To get decimally related output frequencies, the system uses a chain of quintuplers and doublers. The design of these, which was formulated previously, has been perfected in the course of this development.