Abstract: Provided is a process for producing a durable low hydrogen over-voltage cathode. An interim coating is applied to a metallic substrate by plasma spraying an intermetallic compound comprising at least 10% cerium oxide by x-ray diffraction analysis and at least one non-noble Group 8 metal. The metallic substrate bearing the interim coating is then heated in a non-oxidizing atmosphere including an inert gas to produce the electrode.

Abstract: Durable low hydrogen over-voltage cathodes bearing a coating which has an outer layer which comprises at least 10% cerium oxide by XRD and at least one non-noble Group 8 metal. Such cathodes may be prepared by a process involving at least the steps of coating a metallic substrate with an interim coating comprising cerium oxide and at least one non-noble Group 8 metal by plasma spraying an intermetallic compound of cerium and nickel and heating the interim coating in a non-oxidizing atmosphere.

Abstract: A control circuit, particularly for use in a phase-locked loop includes a read-only memory (ROM) having n address inputs divided into two groups, each group being addressed by first (A) and second (B) signals, and the memory device having words preprogrammed therein to provide an output having values (C) of a predetermined function of the first and second signals. In one embodiment the control circuit is employed in a phase-locked loop where one address group provides an analog version of the first signal to a voltage controlled oscillator, and application of the second signal to the second address group permits a step change in the output voltage to the VCO. In another embodiment, the first and second signals may comprise carrier signals and modulating signals in a phase-locked loop employed for frequency modulation.

Abstract: A control circuit comprising a read-only memory has its storage area divided into two areas each containing the same number of addressasble words. By arranging that input of a single address signal causes a change from addressing a particular wood in one area to addressing a corresponding word in the other area, and by programming a fixed difference in value between corresponding words in the two areas causes a step function in the output. Using a digital to analogue converter on the output of the circuit permits a step change in a voltage output to be provided to (e.g.) a voltage controlled oscillator. A control circuit using a read-only memory as a voltage comparator is also disclosed.