電話振鈴之改革

Abstract

A new electronic tone ringer is presented. Basically the circuit of the new ringer can be drived by a 3.5 KHz ringing source, 3 volts in amplitude. The new ringer has the advantages over the convenntional magneto bell ringer in the following respects. System reliability, flatness of frequency response, weight and cost. A prototype was built and tested with satisfactory results.