Abstract: An apparatus and method for the analysis of a periodic signal. One embodiment provides signal values. Signs are assigned to the signal values. The signed signal values are summed to a first sum. At least one signal property is determined on the basis of the first sum.

Abstract: A frequency divider circuit can be utilized for loop-back tests in a transmitter/receiver. In one embodiment, provision is made for a multiplexer to be connected downstream from a frequency divider, whose output side produces signal elements with different phases. The multiplexer is designed to periodically switch its inputs to its output by means of a control signal at its control input. The periodicity of the switching results in a frequency offset with respect to an unswitched signal, by which means a test signal is produced with a difference frequency during frequency conversion. Other systems and methods are also disclosed.

Abstract: The invention provides an apparatus for growing zeolite crystals from an aqueous solution in a metallic pressure tank for admitting pressure to the aqueous solution. Devices for feeding microwave energy into the aqueous solution comprise a capacitor between whose plates the aqueous solution is situated, one of the capacitor plates being formed by a wall of the pressure tank and the other capacitor plate being arranged in the interior of the pressure tank.