A Practical UHF Multidiscriminator Unit (Correspondence)

The purpose of this communication is to report the design and development of a compact UHF multidiscriminator unit. This device offers possible new applications in the microwave systems. Fig. 1 shows the circuit of a single discriminator. A typical discriminator essentially consists of two capacity-loaded strip-line cavities. The strip-line configuration offers compactness and ease of fabrication. The center conductor of each cavity is a printed circuit strip. One side of the strip is connected to the RF circuit as in a conventional coaxial cavity. The other side of this strip is connected to a microwave diode such as a 1N833. One diode is tied to the discriminator output terminal, and the other diode is grounded to the cavity wall with positive polarities of the diodes jointed together by an RF choke (see Fig. 1). The tuning of each cavity is provided by a trimmer capacitor (such as the JFD piston type). Thus, the discriminator can be tuned over a wide range of frequencies simply by varying the capacitance of the trimmers.