The TDA1077 - An I/sup 2/L circuit for two-tone telephone dialing
- 1 June 1977
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Journal of Solid-State Circuits
- Vol. 12 (3) , 238-242
- https://doi.org/10.1109/jssc.1977.1050884
Abstract
The circuit-design aspects of an integrated circuit to perform two-tone telephone dialing are described. The circuit is believed to be unique in that it combines both the crystal-controlled frequency synthesizer and the output amplifier on the same chip. Moreover, no external power supplies are required; the circuit is powered by the telephone-line current. Designed to require a minimum number of external components, the LSI chip provides an economical and accurate two-tone dialing unit. A typical application circuit for existing telephone apparatus is shown and aspects of future development are discussed.Keywords
This publication has 1 reference indexed in Scilit:
- Integrated injection logic: a new approach to LSIIEEE Journal of Solid-State Circuits, 1972