Patent ID: 6243399
Filing Date: 2001-06-05
Classification: H04B,H04M,H04W,Y02D

Abstract:
A ringing signal generator comprising:means for registering a data word representing a selectable one of a plurality of predetermined ringing signal frequencies;means for supplying a clocking signal of a predetermined frequency which is much higher than any of said predetermined ringing signal frequencies;means, responsive to said data word and said clock signal, for generating a low amplitude signal at said selectable one frequency;means for amplifying said clock signal to produce an intermediate signal having both positive polarity and negative polarity portions in each frequency cycle;means for separately half-wave rectifying each of said positive and negative polarity portions;means, responsive to said low amplitude signal, for alternately sampling said separately rectified positive and negative polarity portions;means for low pass filtering an output of said sampling means to produce a ringing signal at a larger amplitude and at said selectable one frequency;means for providing a gating signal of average frequency which is much less than the frequency of said selectable one frequency and having an on-time/off-time duty cycle defining a predetermined ringing signal cadence;means, responsive to said gating signal on-time, for selectively coupling said clock signal to said amplifying means and selectively coupling said low amplitude signal to said alternately sampling means during only said on-time for thereby periodically powering down said ringing signal generator during said off-time of said gating signal.