Abstract: A frequency modulator including a free-running oscillator which is frequency modulated and which is frequency stabilized by means of a reference oscillation by way of a phase control loop having a phase detector and a loop filter. In order to be able to process d.c. components with such a frequency modulator, given a keyed modulation signal, and without abandoning the limitation of the modulation spectrum, the modulation signal is supplied to a control input of the oscillator both by way of a modulation filter and by way of the phase control loop. For this purpose, the phase control loop includes, between the oscillator output and the phase detector, a frequency divider having a division ratio controlled by the modulation signal.

Abstract: An accumulator with plate element of positive and negative electrode plates with interposed separators, lugs on the electrode plates interconnected by connecting straps, and at least one rib secured on the top surface of the plate and separator to secure the plate element to end walls. This enhances the capability of the accumulator to withstand vibration, i.e. makes it shake-resistant.