Abstract: A class of signal dividers and signal filters is disclosed comprising first and second wavepaths coupled at one end to a common input port and at their other ends to a summing network to form a sum signal, and to a differencing network to form a differencing signal. Phase shift means are included along at least one wavepath for producing a differential phase shift between signals in said two wavepaths. In order that such devices be capable of operation at very low frequencies (i.e., a few Hertz), be physically small, and be capable of being made by means of integrated circuit techniques, the phase shifters are made solely of R-C passive elements, or of other devices that can be readily integrated.

Abstract: A method and apparatus are described for reproducing the frequency of an incoming reference signal that persists for only a limited period of time. This is accomplished by counting, during the duration of the reference signal, the number of cycles of a local clock occurring between zero crossings of the reference signal, and storing the count thus obtained. After the termination of the reference signal, a secondary signal is produced whose zero crossing intervals are substantially equal to the stored count multiplied by a period of time that is defined by the local clock. Two applications of frequency sample-and-hold are described.