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US 4,309,574 AGranted
Electronic tone ringer
AssigneeGTE Automatic Electric Labs Inc.
InventorsJohn D. Sublette, William Stobbs
Life of this patent
Estimating the term…
Abstract
An electronic tone ringer for use in telephone substations. This circuit operates in response to conventional ringing signals and generates a single tone alert signal interrupted at a low frequency. The audible tone alert signal is generated by a piezo-ceramic transducer.
Claims11
An electronic tone ringer for use in a telephone subset connected to a telephone line comprising:
- voltage controls means connected to said telephone line, operated in response to ringing signals received over said telephone line, to generate a transducer bias signal;
- transducer means connected to said voltage control means operated in response to said bias signal to generate an audio signal and further operated to generate a feedback signal representative of said audio signal;
- a modulation oscillator connected to said voltage control means operated in response to said transducer bias signal to generate an oscillating control signal of a predetermined low frequency;
- and
- modulation means connected to said modulation oscillator and to said transducer means, operated to modulate said feedback signal with said oscillating control signal, whereby said feedback signal is periodically and alternately enabled and inhibited;
- said transducer means further operated in response to said periodically enabled feedback signal to periodically generate said audio signal.
3 more elements
Dependencies are inferred from the claim text.