Communication system using the electrical power distribution network of a building

Claim 2

In a system for utilizing an electrical signal impressed onto an electrical distribution system wherein said signal has a predetermined frequency other than a carrier frequency of said electrical distribution system, signal responsive means comprising input terminals adapted to be connected to any phase of said electrical distribution system having said electrical signal impressed thereon; a narrow band pass filtering means having a center bandwidth frequency equalling said predetermined frequency and a predetermined bandpass frequency bandwidth, said filtering means having at least two shunt resonant stages and at least one series resonant stage connected between and in parallel to said shunt resonant stages and a resistance means electrically connected across the output of said filtering means and in parallel to said shunt resonant stages, each of said resonant stages having an inductive element and a capacitive element selected of a predetermined value to establish a resonant frequency equalling said predetermined frequency and a bandpass frequency bandwidth which decreases rapidly as a function of frequency between the - 3 db power level point and the -40 db power level point on each side of said predetermined frequency which in combination substantially reject electrical signals having a frequency slightly different from said predetermined frequency while selectively passing electrical signals substantially at said predetermined frequency; and circuit means electrically connected to said filtering means for responding to an electrical signal having a frequency substantially at said predetermined frequency selectively passed by said filtering means.

Claim 3

The system of claim 1 wherein said signal responsive means further includes means operatively coupled to said input terminals for passing to said filtering means electrical signals having a frequency in the range of said predetermined frequency with relatively low attenuation and for substantially blocking electrical signals having a frequency in the range of said carrier frequency.

Claim 4

The system of claim 1 wherein said filtering means comprises at least a five stage filter including three shunt resonant stages and two single series resonant stages connected between and in parallel to each of said shunt series stages and the inductive element and capacitive element of each resonant stage are selected of predetermined values to establish a bandpass frequency bandwidth at the -40 Db power level which varies about twenty percent from the predetermined frequency.

Claim 5

The system of claim 3 wherein said filtering means includes a first resistor having a predetermined resistance electrically connected between and in series to said input terminals and said filtering means and wherein said resistance means is a second resistor having the same resistance as said first resistor electrically connected to the output of said filtering means and in parallel to said shunt resonant stages. In a system for utilizing an electrical signal impressed onto an electrical distribution system wherein said signal has a predetermined frequency other than a carrier frequency of said electrical distribution system, signal responsive means comprising input terminals adapted to be connected to said electrical distribution system; a narrow band pass filtering means having a center bandwidth frequency equalling said predetermined frequency; a first resistor having a predetermined resistance electrically connected between and in series to said input terminals and said filtering means; said filtering means having at least a five stage filter including three shunt resonant stages and two single series resonant stages connected between and in parallel to each of said shunt series stages; a second resistor having the same resistance as said first resistor electrically connected to the output of said filtering means and in parallel to said shunt resonant stages, each of said resonant stages having a frequency equalling said predetermined frequency which in combination substantially reject electrical signals having a frequency slightly different from said predetermined frequency while selectively passing electrical signals substantially at said predetermined frequency; a first unilaterally conducting device electrically connected between said input terminal and said first resistor and in parallel to said series resonant stages; a second unilaterally conducting device electrically connected in parallel to and in a direction opposite to said first unilaterally conducting device, said first and second uni; aterally conducting devices being operative to clamp electrical signals having a potential which exceeds the potential drop across said first and second unilaterally conducting devices; and circuit means electrically connected to said filtering means for responding to an electrical signal having a frequency substantially at said predetermined frequency selectively passed by said filtering means.

Claim 6

The system of claim 5 wherein said circuit means includes at least a one stage amplifier operatively connected to said filtering means to receive and amplify said electrical signal having a frequency substantially equalling said predetermined frequency; a voltage doubling circuit including a capacitor electrically connected to said amplifying means for doubling the amplified signal and for charging said capacitor to a predetermined level in response to said doubled amplified signal; and a switching circuit having a first and second state electrically connected between said voltage doubling circuit and a load, said switching circuit being capable of being switched from said first state to a second state to actuate said load when the charge on said capacitor reaches said predetermined level.

Claim 7

In a multifrequency system for utilizing multifrequency electrical signals impressed onto an electrical distribution system wherein said multifrequency electrical signals are separated by a discrete frequency difference and each such electrical signal is at a frequency other than a carrier frequency of said electrical distribution system, signal responsive means comprising input terminals adapted to be connected to any phase of said electrical distribution system having said multifrequency electrical signals impressed thereon; a plurality of narrow band pass filtering means each having a different preselected center Bandwidth frequency corresponding to the frequency of one of said multifrequency electrical signals and a predetermined bandpass frequency bandwidth, each of said filtering means having at least two shunt resonant stages and a series resonant stage connected between and in parallel to said shunt resonant stage and a resistance means electrically connected across the output of said filtering means and in parallel to said shunt resonant stages, each of said resonant stages having an inductive element and a capacitive element selected of a predetermined value to establish a resonant frequency equalling the preselected frequency of its associated filtering means and a bandpass frequency bandwidth which decreases rapidly as a function of frequency between the -3 db power level point and the -40db power point on each side of said preselected frequency which selectively pass electrical signals at substantially the preselected frequency of its associated filtering means while substantially rejecting electrical signals having a frequency slightly different from said preselected frequency of its associated filtering means, and circuit means electrically connected to said plurality of filtering means for responding to any of said electrical signals at substantially the preselected frequency passed by any of said filtering means.

Claim 8

In a multifrequency system for utilizing multifrequency electrical signals impressed onto an electrical distribution system wherein said multifrequency electrical signals are separated by a discrete frequency difference and each such electrical signal is at a frequency other than a carrier frequency of said electrical distribution system, signal responsive means comprising input terminals adapted to be connected to any phase of said electrical distribution system having said multifrequency electrical signals impressed thereon; a plurality of narrow band pass filtering means each having a different preselected center Bandwidth frequency corresponding to the frequency of one of said multifrequency electrical signals and a predetermined bandpass frequency bandwidth, each of said filtering means having at least two shunt resonant stages and a series resonant stage connected between and in parallel to said shunt resonant stage and a resistance means electrically connected across the output of said filtering means and in parallel to said shunt resonant stages, each of said resonant stages having an inductive element and a capacitive element selected of a predetermined value to establish a resonant frequency equalling the preselected frequency of its associated filtering means and a bandpass frequency bandwidth which decreases rapidly as a function of frequency between the -3 db power level point and the -40db power point on each side of said preselected frequency which selectively pass electrical signals at substantially the preselected frequency of its associated filtering means while substantially rejecting electrical signals having a frequency slightly different from said preselected frequency of its associated filtering means, and circuit means electrically connected to said plurality of filtering means for responding to any of said electrical signals at substantially the preselected frequency passed by any of said filtering means.

Claim 9

The multifrequency system of claim 7 wherein said signal responsive means further includes means operatively coupled to said input terminals for passing to said plurality of filtering means said multifrequency electrical signals with relatively low attenuation and for substantially blocking electrical signals having a frequency in the range of said carrier frequency.

Claim 10

The multifrequency system of claim 7 further including an annunciator electrically connected to said plurality of filtering means and responsive to an electrical signal passed by any of said filtering means for indicating which of said filtering means passed said signal.

Claim 11

A communication system adapted for use with a building''s electrical distribution system comprising means for transmitting a high frequency signal over said electrical distribution system, said transmitting means including means for generating a high frequency signal having a predetermined frequency, means operatively coupled to said generating means for impressing said high frequency signal on said electrical distribution system for modulating the alternating current voltage, and means operatively coupled to said generating means for selectively rendering said generating means operative to impress upon and transmit said high frequency signal over said electrical distribution system, and means operatively coupled to any phase of said electrical distribution system for receiving said high frequency signal when said transmitting means transmits a high frequency signal over said electrical distribution system, said receiving means including a narrow band pass filtering means having a center bandwidth frequency equalling said predetermined frequency and a bandpass frequency bandwidth substantially defined by the -3db power level point on each side of said center bandwidth frequency on a rapidly decreasing roll-off power level characteristic between each -3db power level point and its respective -40 db power level point, said filtering means including at least two shunt resonant stages and a single series resonant stage connected between and in parallel to said shunt resonant stages and a resistance means electrically connected across the output of said filtering means and in parallel to said shunt resonant stages, each of said resonant stages having passive elements and a center bandwidth equalling said predetermined frequency, said filtering means being capable of passing said high frequency signal with minimum attenuation and passing all other signals with substantial attenuation whereby the signal-to-noise ratio of thE passed high frequency signal is substantially greater than that of the received high frequency signal, amplifying means operatively coupled to said filtering means for amplifying said passed high frequency signal, and circuit means operatively coupled tp said amplifying means and responsive to an amplified high frequency signal for actuating an output device.

Claim 12

A communication system adapted for use with a building''s electrical distribution system comprising means for transmitting a high frequency signal over said electrical distribution system, said transmitting means including means for generating a high frequency signal having a predetermined frequency, means operatively coupled to said generating means for impressing said high frequency signal on said electrical distribution system for modulating the alternating current voltage, and means operatively coupled to said generating means for selectively rendering said generating means operative to impress upon and transmit said high frequency signal over said electrical distribution system, and means operatively coupled to any phase of said electrical distribution system for receiving said high frequency signal when said transmitting means transmits a high frequency signal over said electrical distribution system, said receiving means including a narrow band pass filtering means having a center bandwidth frequency equalling said predetermined frequency and a bandpass frequency bandwidth substantially defined by the -3db power level point on each side of said center bandwidth frequency on a rapidly decreasing roll-off power level characteristic between each -3db power level point and its respective -40 db power level point, said filtering means including at least two shunt resonant stages and a single series resonant stage connected between and in parallel to said shunt resonant stages and a resistance means electrically connected across the output of said filtering means and in parallel to said shunt resonant stages, each of said resonant stages having passive elements and a center bandwidth equalling said predetermined frequency, said filtering means being capable of passing said high frequency signal with minimum attenuation and passing all other signals with substantial attenuation whereby the signal-to-noise ratio of thE passed high frequency signal is substantially greater than that of the received high frequency signal, amplifying means operatively coupled to said filtering means for amplifying said passed high frequency signal, and circuit means operatively coupled tp said amplifying means and responsive to an amplified high frequency signal for actuating an output device.

Claim 13

The communication system of claim 10 further including temperature sensing means capable of being actuated at a predetermined temperature level electrically connected to said transmitting means for starting said high frequency signal generating means when the ambient temperature in the vicinity of said temperature sensing means reaches a predetermined temperature level; and wherein said output device is an alarm means for indicating actuation of said temperature sensing means.

Claim 14

The communication system of claim 10 further including intrusion detecting means capable of being actuated when any one of an object, person and the like is detected in the vicinity of said intrusion detecting means for starting said high frequency signal generating means when said intrusion detecting means is actuated; and wherein said output device is an alarm means for indicating actuation of said intrusion detecting means.

Claim 15

The communication system of claim 10 further including means including a rechargeable battery operatively connected to said receiving means for charging said battery to a predetermined charge level when said electrical distribution system energizes said receiving means and for supplying a direct current voltage to said receiving means when said electrical distribution system is de-energized.

Claim 16

The communication system of claim 13 wherein said receiving means includes a supervisory control circuit including a trouble annunciator for indicating at least one of said receiving means being energized from said battery and said output device being incapable of responding to said circuit means.