초록 ▼

Some circuit components are powered down by switching their power supply circuits. In order to minimize the extent of circuitry that must be provided to distribute power consumption control signals, other techniques (which utilize circuitry provided for other purposes), such as clock frequency contr

Some circuit components are powered down by switching their power supply circuits. In order to minimize the extent of circuitry that must be provided to distribute power consumption control signals, other techniques (which utilize circuitry provided for other purposes), such as clock frequency control or power down commands, also are utilized to modify controlled circuit component power consumption without actually controlling power supply circuits. Loop connection length between the subscriber unit and the subscriber's telephone set, or other terminal equipment, is limited to a length which is much less than the length of a radio link on which the subscriber unit operates. Programmable ring frequency logic controls the frequency of a ringing signal generator, and a high frequency ring control signal is switched on and off in the cadence of ringing operation. Also an expansion header is provided to enable serving plural subscriber loop circuits with the same radio equipment for reducing per line power consumption.

대표청구항 ▼

[ What is claimed is:] [1.]1. 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 pred

[ What is claimed is:] [1.]1. 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.