A method of producing voltage signals with a dc component and great dynamic range

摘要

A method for producing a high level voltage signal (e.g. ringing voltages) for a telephone system is described. Each cycle of the signal is comprised of one positive half cycle of one frequency followed by one negative half cycle of a lower frequency (for a negative DC component). The two frequencies are chosen such that the total period, for the tho half cycles, constitutes one cycle at the frequency of the high level voltage signal desired. This method is well suited to implementation by a ROM controlled signal generator.