Progress in Optigal Frequengy Measurement At NRLM

Abstract

Frequency Chain Our frequency chain to methane-stabilized 3.39 pm is shown in Fig.1. The chain consists of three stages and almost t e same as the one used in other standard laboratories23. We adopted the Josephson Junction point contact diode (J-J diode) as a harmonic-generator mixer at first stage of the mixing. The J-J diode can generally produce higher harmonics ( the highest we ever obtained?) is the 83rd of 50 GHz) than the other mixers, which enables us to use the cheaper microwave sources and components. At the other two mixing stages, W-Ni point contact diodes are used as a h~rnonic-generator zixeI-.