a detailed descriptions of an embodiment of the invention is provided herein . it is to be understood , however , that the present invention may be embodied in various forms . therefore , the specific details disclosed herein are not to be interpreted as limiting , but rather as a representative basis for teaching one skilled in the art how to employ the present invention in virtually any detailed system , structure , or manner . turning first to fig1 a and 1 b , an emission unit comprises a casing ( e 1 ) that may have a cover ( e 2 ), a control unit ( e 3 ), one or more light emitters ( e 4 ) and one or more sound emitters ( e 5 ). the casing ( e 1 ) and the relevant cover ( e 2 ) contain the control unit ( e 3 ), as well as the sound emitters ( e 5 ) and light emitters ( e 4 ), protecting these components from the weather . in particular , the cover ( e 2 ) of the casing ( e 1 ) is totally or partially connected to a lifting mechanism ( e 22 ) that provides for the opening or closing of the cover , depending on whether the emission unit is to be protected or not from the weather . light emitters ( e 4 ) and sound emitters ( e 5 ) are preferably housed inside the cover ( e 2 ). when the cover ( e 2 ) is completely open , the light emitters ( e 4 ) and sound emitters ( e 5 ) are directed in an upward direction . instead , when the cover ( e 2 ) is in an only partially open position , to protect the inside from the weather , the light emitters ( e 4 ) and sound emitters ( e 5 ) are directed towards a preferably reflecting surface that also protects the control unit ( e 3 ). inside the casing ( e 1 ) there are the control unit ( e 3 ) and the amplification unit , whose connections and operation are diagrammatically represented in fig2 . the light emitters ( e 4 ) are preferably constituted by one or more stroboscopic lights or similar lights inserted in the cover ( e 2 ). the sound emitters ( e 5 ) are preferably constituted by a set of loudspeakers or acoustic diffusers with high efficiency and high pass - band connected to a power amplifier . said sound emitters ( e 5 ) are preferably inserted in the cover ( e 2 ). the control unit ( e 3 ) comprises a logic circuit for management , self - diagnosis and communication with a pilot system ( p ), as well as a noise generator . the part of the logic circuit in control unit ( e 3 ) relevant to management , self - diagnosis and communication provides for monitoring the correct operation of the entire emission unit , for transmitting the correct operation or malfunction report to the pilot system ( p ), for setting and operating the noise generator , for operating the light emitters ( e 4 ) and sound emitters ( e 5 ) and the cover ( e 2 ) lifting mechanism ( e 22 ). the part of the control unit ( e 3 ) related to the noise generator , diagrammatically represented in fig3 , substantially comprises a first device ( e 31 ) for generating variously modulated wave forms , which can be emitted in predefined manner , such as at random or in a predetermined manner , for example through a complex algorithm , and a second device ( e 32 ) for generating predetermined sounds , for example blasts , explosions , howls , or bursts . said two modules ( e 31 , e 32 ), are capable of producing signals with different types of modulation in a wide spectrum of audible and ultrasonic frequencies with emission level variations , both at random and piloted . the first and second devices ( e 31 , e 32 ) can be used separately or together , by means of an apposite adder ( ad 2 ) and the relevant switches ( sw 4 , sw 5 ), for the production of more or less complex noise effects . the related signals are sent to a suitable power amplifier that is in turn connected to the sound emitters ( e 5 ). the wave form generator ( e 31 ) comprises a frequency modulator ( fm ) followed by an adder ( ad 1 ) and by an amplitude modulator ( am ). the three stages are powered by as many generators of modulating frequencies ( mg 1 , mg 2 and mg 3 ) and by a carrier frequency generator ( cg ). the frequency and amplitude of each generator ( mg 1 , mg 2 and mg 3 ) are variable within predefined limits and are piloted at random or in a predetermined manner , depending on the desired sound effect . it is possible to exclude one or more generators ( mg 1 , mg 2 and mg 3 ) by means of apposite switches ( sw 1 , sw 2 , sw 3 ), in order to obtain different signal combinations . the carrier ( cg ) and modulating frequency ( mg 1 , mg 2 , mg 3 ) generators are all of the frequency synthesis type and both their frequency and amplitude can be modified through the control unit ( e 3 ). the above described emission unit is connected to the pilot system ( p ). the pilot system ( p ) is built in similar fashion to an emission unit and comprises a casing with or without an opening cover , a control circuit , an amplification unit , one or more light emitters and one or more sound emitters . besides , pilot system ( p ) is provided with suitable interfaces for connection to the various emission units and with a radio connection module for connection to a control unit ( c ). the various control units ( c ), pilot systems ( p ) and emission units ( e ) are connected to one another as diagrammatically shown in fig4 to protect an area ( l ), for example the strip of an airport . the pilot system ( p ) substantially receives from the control unit ( c ) the operating configuration of all the emission units ( in fig4 , emission units ea - ef ), sends the relevant commands to each emission unit ( ea - ef ), and also receives from each emission unit ( ea - ef ) the relevant correct operation or malfunction report transmitting it to the control unit ( c ). the control unit ( c ) preferably comprises a computer , with wire or radio communication system for connection to the pilot system ( p ), together with dedicated software . the control unit ( c ) makes it possible to constantly monitor the correct operation of all the pilot systems ( p ) and emission units , to set the operating mode for each emission unit through a program capable of activating the light emitters ( e 4 ) and sound emitters ( e 5 ), as well as of defining the sequences and combinations of sound and light signals for groups of emission units or for single emission units , whether in a predetermined , pseudo - random , or random manner . the operation of the new device for keeping birds away with differential management functions requires that both the emission units ( ea - ef ) and each pilot system ( p ) have the possibility to operate individually or to be coordinated . in both cases management is carried out by the pilot system ( p ), duly piloted by the control unit ( c ). in each case the time schedule and the characteristics of the sound and light signals will be determined by the pilot system ( p ) in combination , wherein the combination is predetermined , pseudo - random , or random . for example , it will be possible to obtain the emission of independent random signals from each emission unit , wherein each unit will emit a different random signal , or of random signals depending on the pilot system ( p ), wherein all emission units will emit the same random signal . the emission units can emit different or identical sounds in different sequences ( linear sequence , alternate sequence , chessboard sequence , etc .). for example , in the case of six emission units ( ea - ef ), some of the possible sequences may be the following : ea , ed , eb , ee , ec , ef ; ea ee ec together , ed eb ef together ; ea , eb , ec , ef , ee , ed ; ea eb ec together , ed ee ef together ; ea , eb , ec , ed , ee , ef ; ea eb ec ed ee ef together ; ea ed together , eb ee together , ec ef together . the beginning , the duration , and the sound characteristics of each stage of a sequence can be varied by the pilot system ( p ) in a random , pseudo - random or predetermined manner . even when the operation of the emission units is completely independent and randomized , it is possible to still set some parameters , such as a combination of parameters , for example the range of carrier and modulating frequencies emitted , the maximum and minimum duration of each stage , or the minimum and maximum amplitude of each signal . it is also possible to provide for the operation of sub - groups of emission units ( ea - ef ) according to specific areas to be covered : for example ec and ef may operate independently and at random , while ea , eb , ed and ee may be activated in a piloted manner . the new device for keeping birds away with differential management functions offers considerable advantages over the prior art . there are no fixed time and / or frequency intervals between the emission of sound and / or light signals , and therefore the birds cannot know in advance when a given signal is going to start and / or to end . there are no continuous acoustic signals and / or flashes that allow the birds to become accustomed to these types of signals . operating times , emitted frequencies , and synchronization , succession or independence among the various units makes the sound and / or light emissions of the set of emission units completely unpredictable , which prevents the birds from memorizing the operating times and sequences of the various emission units . the operation of each emission unit in the self - diagnosis mode and the consequent report on its operating condition to the control unit ( c ) through the pilot system ( p ) make it possible to constantly verify the correct operation of all the emission units , thus allowing also the necessary maintenance operations and repairs to be carried out on the emission units that may be functioning incorrectly and on the specific malfunctioning devices . while the invention has been described in connection with the above described embodiment , it is not intended to limit the scope of the invention to the particular forms set forth , but on the contrary , it is intended to cover such alternatives , modifications , and equivalents as may be included within the scope of the invention .
a device for keeping birds away with differential management functions , comprising a control unit connected to a pilot system that controls one or more emission units . the pilot system and each emission unit comprise a casing with an optional protection cover and lifting mechanism ; a control circuit ; and one or more light and sound emitters . the control unit controls the light and sound emitters , receives operating instructions from the pilot system , and verifies the correct operation of all components of the unit . the control unit preferably comprises a computer with radio or wire communication capability , constantly monitors the correct operation of all pilot and emission units , sets the operating mode for each emission unit , determines and varies the sequences and combinations of the sound and light signals emitted by groups of emission units or by individual emission units , and develops the operating schedule for the entire system .