Abstract:
The method and apparatus includes an uninterruptible power supply along with its rechargeable battery and a plurality of video protection circuits all within a common chassis. The video protection circuits are configured to protect the digital video recorder from surges introduced at the video cameras or cabling. The uninterruptible power supply is configured to provide power to the digital video recorder should a line voltage power failure occur and may also include a surge protector to further protect the digital video recorder from power line surges. Since all components are housed substantially within a common chassis, a method of isolating the video protection circuit and associated connectors from the radio frequency noise within the common chassis is described as well as a method and apparatus to allow removal and replacement of the video protection circuits should a power surge destroy them.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to a method and apparatus for protecting various components of a digital video recording system.  
         [0003]     2. Description of the Prior Art  
         [0004]     Video monitoring systems often utilize a number of remotely located video cameras connected to one or more video recorders, perhaps such cameras are located in key locations to monitor various locations, grounds or entry ways to businesses and homes. These remotely located video cameras are most often connected to a video recorder or video switching system by, for example, coaxial cables that include a signal path and a ground/shield. Unfortunately, since video often operates at relatively low voltages, the video recorder is susceptible to unusual line conditions such as surges resulting in over-voltage or over-current conditions. If the camera or cabling is exposed to such a surge in electricity, that electricity may flow down the coaxial cable and may damage the video switching system and/or the video recorder. This may arise during an electrical storm, especially if lightning strikes near or at the video camera. Furthermore, voltage fluctuations, surges and other line variations may travel into a building over phone lines, data lines and/or power lines with the potential to damage the recorder and/or video switching system. In addition, it is possible to lose power to the recorder/switching system, which may impact the ability of the video recorder to monitor the remote video cameras.  
         [0005]     In the past, several discrete products protected these recording/switching systems. Power to the recording/switching system may have been conditioned by a surge protector to reduce the risk of power surges emanating from building power. Additionally, to provide power to the recording/switching system in the event of a power outage or shortage, an uninterruptible power supply (UPS) may have been used, perhaps a UPS with an integrated surge protector. In addition, another system comprising one or more video surge protectors may have been added to help protect the video recorder from surges emanating from the video cameras or the cabling that connects the cameras to the video recorder. Additionally, if network connections or phone connections are made to the video recorder, discrete network surge protectors and phone line protectors may have been deployed.  
         [0006]     What is needed is an integrated system to protect the video monitoring system from external power surges, electrostatic discharge, lightning and other hazardous forces, while providing back-up power to the monitoring system in the event of a power outage.  
       SUMMARY OF THE INVENTION  
       [0007]     For the purposes of this application, the term video monitoring system will include the video cameras, cabling, video switching, video display and video recording components. The video recording components may be analog or digital recorders. Reference to the video recording system will encompass any recording equipment, including video switching, decoding, recording and display.  
         [0008]     In one embodiment, a system for protecting a digital video recording system is provided, housed within a metal chassis. The system includes a battery and an uninterruptible power supply for providing power during a power disruption. The system also includes a line voltage input for providing power from a power source external to the metal chassis and a surge protection circuit also housed within said metal chassis and at least one female line voltage output connector configured to receive power from the uninterruptible power supply attached to the metal chassis and passing through a wall of the metal chassis. Further included is a plurality of video surge protectors each having a video input connector, a video output connector and a surge protection circuit and each mounted upon a conductive plate. The conductive plate is configured to cover an opening in the metal chassis and is affixed thereto. Each of the plurality of video surge protectors is electrically isolated from the rest and is electrically isolated from the metal chassis.  
         [0009]     In another embodiment, an apparatus for protecting a digital video recording system is provided, housed within a metal chassis. The apparatus includes a plurality of video surge protectors each having a video input connector, a video output connector and a surge protection circuit and each mounted upon a conductive plate. The conductive plate is configured to cover an opening on the metal chassis and affixed to the metal chassis. Each of the plurality of video surge protectors is electrically isolated from the rest and each is electrically isolated from the metal chassis. A metal shield is electrically and physically attached to cover the opening in the metal chassis and is affixed on an inside surface of the metal chassis so the metal shield substantially covers the video surge protectors and effectively shields them from interference from active devices housed within the metal chassis.  
         [0010]     In another embodiment of the present invention, an apparatus for protecting a digital video recording system is provided. This includes a metal chassis with a plurality of video surge protectors each having a video input connector, a video output connector and a surge protection circuit. The video surge protectors are mounted on a conductive plate that is configured to cover an opening in the metal chassis and affixed thereto. The video surge protectors are electrically isolated from each other and are electrically isolated from the metal chassis. A metal shield covers the opening of the metal chassis and is electrically and physically attached to cover the opening of the metal chassis on an inside surface. The metal shield substantially covers the video surge protectors, effectively shielding the video surge protectors from interference from other devices housed within said metal chassis. Also included is an uninterruptible power supply housed within and mounted to the metal chassis, a power line surge protector also housed within and mounted to the metal chassis, a telephone line protection module substantially housed within and mounted to the chassis and a network protection module, also substantially housed within and mounted to the chassis.  
         [0011]     In another embodiment of the present invention, a means for protecting a digital video recording system is provided, including a means for enclosing electronic circuitry, a means for providing a plurality of video surge protectors, each having a video input connector, a video output connector and a surge protection circuit. Also included is a means for mounting the plurality of video surge protectors on a conductive plate covering an opening in the means for enclosing as well as a means for shielding the plurality of video surge protectors physically attached to cover the opening on an inside surface and substantially covering the plurality of video surge protectors, effectively shielding them from interference emanating from other devices housed within the means for enclosing. Also included is a means to provide uninterrupted power to an external device, also mounted within the means for enclosing.  
         [0012]     In another embodiment of the present invention, a method of protecting a digital video recording system is disclosed providing a plurality of video surge protectors each having a video input connector, a video output connector and a surge protection circuit and mounting them on a conductive plate. Additionally an uninterruptible power supply is provided and the video surge protectors are shielded from the uninterruptible power supply to reduce radio frequency noise that may interfere with video signals. The video surge protectors and uninterruptible power supply are enclosed within a metal chassis. In this, the conductive plate is affixed to the metal chassis so that each of the video output connectors and each of the video input connectors is accessible from outside of the metal chassis and the video surge protectors are shielded from the uninterruptible power supply. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:  
         [0014]      FIG. 1  illustrates a rear view of an embodiment of the present invention.  
         [0015]      FIG. 2  illustrates a rear view of an embodiment of the present invention with the top cover partially removed.  
         [0016]      FIG. 3  illustrates a front view of an embodiment of the present invention with the top cover removed.  
         [0017]      FIG. 4  illustrates a cut-away top view of an embodiment of the present invention.  
         [0018]      FIG. 5  illustrates a cut-away top view of an embodiment of the present invention.  
         [0019]      FIG. 6  illustrates a schematic view of an embodiment of the present invention.  
         [0020]      FIG. 7  illustrates a schematic view of an embodiment of a video protection module of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.  
         [0022]     Throughout the following detailed description, the same reference numerals refer to the same elements in all figures.  
         [0023]     Referring to  FIG. 1 , a back view of the present invention is shown. The system is enclosed in a metal chassis  105 , preferably, metal such as aluminum, copper or steel. The chassis may be painted or not, or may be enclosed by an outer shell made of, perhaps, an insulative material such as plastic without veering from the present invention. Shown is a field of video connectors, half of which are video input connectors and the other half are video output connectors. For example, connector  110  is a video input connector and connector  120  is a video output connector. In this example, there are 16 video input connectors and 16 video output connectors, but any number of video input and video output pairs may be provided without veering from the present invention. In this embodiment, the video input connectors are BNC connectors, but in other embodiments some or all may be twisted pair connectors. Furthermore, in some embodiments some inputs may be of one type of connector and some outputs may be of another type of connector and a Balun may be provided to convert between types of video transmission line. The video input and output connectors are mounted on a conductive plate  190  and the conductive plate is fastened to the metal chassis with four fasteners  195 , though any number of type of fastener my be used. In this way, if a power surge on one or more of the video connectors destroys a surge protection circuit, the field of video connectors and their associated surge protection circuits may be removed from the metal chassis  105  by unfastening the fasteners  195 , removing the conductive plate  190  along with the video connectors  110 / 120  and protection circuits and replacing it with a new conductive plate  190  with new video connectors  110 / 120  and video protection circuits.  
         [0024]     Also shown in this example is a line voltage input  130 , in this example, a North American standard 120V line cord is shown, though in other embodiments, this could be a different line input, perhaps a DC line input or a different AC voltage, frequency or connector. Additionally, there are four female line voltage output connectors ( 140  and  150 ) for providing power to a protected device. In some embodiments, the female line voltage output connectors ( 140  and  150 ) are connected directly to the line voltage input. In other embodiments one or more of the female line voltage output connectors ( 140  and  150 ) are connected to the line voltage input through one or more surge protectors. Still yet in other embodiments, one or more of the female line voltage output connectors ( 140  and  150 ) may be connected to a uninterruptible power supply which is in turn connected to the line voltage input and is configured to provide line voltage output should the line voltage input fail, perhaps in a power outage. Any combination of direct connection, surge protection or uninterruptible power supply configurations may be used without veering from the present invention. This uninterruptible power supply is just one example of an active device that may be housed within the same metal chassis as the video surge protectors.  
         [0025]     Also shown in  FIG. 1  are two network connectors, a network input connector  160  and a network output connector  165 . In some embodiments, a network protection module is provided to protect data networks from power surges and that protection module is configured to protect network devices connected to one network connector of the system from power surges emanating from devices on the other network connector.  
         [0026]     Also shown in  FIG. 1  are two phone line connectors, a phone line input connector  170  and a phone line output connector  175 . In some embodiments, a phone line protection module is provided to protect phone networks and equipment from power surges and that protection module is configured to protect phone line devices connected to one phone line connector of the system from power surges emanating from devices on the other phone line connector.  
         [0027]     Also shown in  FIG. 1  is a set of dry contacts  180 . In some embodiments, these are provided so that the status of the system may be monitored from remote locations.  
         [0028]     Also shown in  FIG. 1  is a reset button  185  for, in some embodiments, resetting the system after a fault is detected and then cleared.  
         [0029]      FIG. 2  shows a back view of the present invention with the cover  210  removed, exposing internal components. The system is enclosed in a metal chassis  105 , preferably metal such as aluminum, copper or steel. The chassis may be painted or not, or may be enclosed by an outer shell made of, perhaps, an insulative material such as plastic without veering from the present invention. Shown is a field of video connectors, half of which are video input connectors and the other half are video output connectors. For example, connector  110  is a video input connector and connector  120  is a video output connector. In this example, there are 16 video input connectors and 16 video output connectors, but any number of video input and video output pairs may be provided without veering from the present invention. The video input and output connectors are mounted on a conductive plate  190  and the conductive plate is fastened to the metal chassis with four fasteners  195 , though any number of type of fastener my be used. In this way, if a power surge on one or more of the video connectors destroys the protection circuit, the field of video connectors and their associated surge protection circuits may be removed from the metal chassis  105  by unfastening the fasteners  195 , removing the conductive plate along with the video connectors and protection circuits and replacing it with a new conductive plate with new video connectors and protection circuits.  
         [0030]     In  FIG. 2 , internal components are visible, including the line surge protector and uninterruptible power supply module  220  and a battery  230  for power back up. Also, the top of a metal shield  240  that is configured to shield the field of video connectors and their protection circuits from noise generated by other circuits within the metal chassis is shown.  
         [0031]     Referring to  FIG. 3 , a front view of the present invention is shown with the cover removed and internal components are visible, including the line surge protector and universal power supply module  220  and a battery for power back up  230 . Also, the back of the metal shield  240  that is configured to shield the field of video connectors and their protection circuits from noise generated by other circuits within the metal chassis is shown. The top row of video connectors can be seen, for example, video input connector  110 . In some embodiments, an uninterruptible power supply load monitoring circuit is supplied with a display  380  that indicates the load being drawn from the power output connectors ( 140  and  150  from  FIG. 1 ). As shown, this display  380  can be a set of light emitting diodes (LEDs) forming a bar graph, whereas, the right most LED may indicate a small load amount and the left most LED may indicate a large load amount, so as the load increases, the LEDs light from right to left. The LEDs may be configured in an additive scheme and may be assigned linear power increments or logarithmic power increments. In other embodiments, the LEDs may be colored; perhaps the lower current LED being green, the medium current LED being yellow and the highest current LED being red. In alternate embodiments, a meter or digital display can be used instead of the LEDs or any other current indicator may be used.  
         [0032]     Also show in  FIG. 3  is a network protection circuit  360 . In some embodiments, a network protection module is provided to protect data networks from power surges and that protection module is configured to protect network devices connected to one network connector of the system from power surges emanating from devices on the other network connector.  
         [0033]     Also show in  FIG. 3  is a phone line protection circuit  370 . In some embodiments, a phone line protection module is provided to protect phone networks and equipment from power surges and that protection module is configured to protect phone line devices connected to one phone line connector of the system from power surges emanating from devices on the other phone line connector.  
         [0034]      FIG. 4  shows a cut away view of the back of the metal chassis  105  looking down from the top, showing the field of video connectors mounted to the conductive plate  190 . When engaged within the metal chassis  105 , the conductive plate  190  is affixed to the metal chassis  105  by a plurality of fasteners  195 . Connected to the component side of the video connectors is a video protection circuit board  420 , containing an isolated video protection circuit  710  for each video input/output pair, for example. The video protection circuits  710  may protect a variety of video standards operating at various peak-to-peak voltages, including providing protection at either 2.8 volts or 6.8 volts. In some embodiments, the video protection circuit  710  may also include video transmission conversion circuits, perhaps to convert between video transmission schemes and impedances, perhaps converting between a COAX transmission scheme and a twisted-pair transmission scheme or visa versa. In this example, a top row of video inputs  110  is shown as BNC connectors, and the video outputs, also BNC connectors) are hidden. In alternate embodiments, the inputs may be BNC for COAX connection and the outputs may be connectors for twisted pair connectors or visa versa.  
         [0035]     Surrounding the video protection circuit board  420  is a conductive shield  240  which may be made from a metal such as copper, aluminum or steel. In this embodiment, the conductive shield  240  is affixed to the conductive plate  190 .  
         [0036]      FIG. 5  shows a cut away view of the back of the metal chassis  105  looking down from the top, showing the field of video connectors mounted to the conductive plate  190 . When engaged with the metal chassis  105 , the conductive plate  190  is affixed to the metal chassis  105  by a plurality of fasteners  195 . Connected to the component side of the video connectors is a video protection circuit board  420 , containing an isolated video protection circuit for each video input/output pair, for example. In some embodiments, the video protection circuit may also include video transmission conversion circuits, perhaps to convert between video transmission schemes and impedances, perhaps converting between a COAX transmission scheme and a twisted-pair transmission scheme or visa versa. In this example, a top row of video inputs  110  is shown as BNC connectors, and the video outputs, also BNC connectors) are hidden. In alternate embodiments, the inputs may be BNC for COAX connection and the outputs may be pluggable terminal blocks for twisted pair connectors such as a Molex 5.08 mm pitch BeauEurostyle® Pluggable PCB Terminal Block or visa versa.  
         [0037]     Within the metal chassis  105  and configured to surround the video protection circuit board when the conductive plate  190  is installed on the metal chassis  105 , is a conductive shield  240  which may be made from a metal such as copper, aluminum or steel. The conductive shield  240  is affixed to the metal chassis  105  at points  430  by any means known in the industry including welding, tack soldering and fastening with a plurality of fasteners.  
         [0038]      FIG. 6  shows a schematic diagram  600  of the present invention. In this, a video camera  610  is connected to a video input connector  110 , which is electrically isolated from the metal chassis  105 . The video signal from the camera  610  passes through the video input connector  110  and onto a video protection circuit board  420 , on which a video protection circuit helps prevent potentially harmful electrical surges from passing through to the video output connector  120 . The video signal passes through the video output connector  120  and to a digital video recorder  620 . In some embodiments, the video signal passes through a video multiplexor or switch (not shown) before reaching the digital video recorder  620 .  
         [0039]     Also within the metal chassis  105  is an uninterruptible power supply consisting of a battery  230  and an inverter/uninterruptible power supply (UPS)/charger  640 . The inverter portion converts the battery voltage to the desired output voltage when the input power is lost or reduced. The uninterruptible power supply monitors the input power and determines if it can charge the battery using the charger or if it has to supply power from the battery using the inverter. The uninterruptible power supply receives input power from a line voltage input  130  that is protected by a surge protector  630  before reaching the uninterruptible power supply  640 . Together, the surge protector  630  and inverter/UPS/charger  640  may be enclosed in one package or on a single circuit board  220 . In some embodiments, the output of the uninterruptible power supply goes through the load monitor circuit  660  and to the line voltage output connectors  140 . In other embodiments, the output of the uninterruptible power supply goes directly to the line voltage output connectors  140 . In this example two female power output connectors are shown, but there are no restrictions on the number of line voltage output connectors that may be present. The digital video recorder&#39;s  620  power input plug  625  may be plugged into one of the line voltage output connectors  140  so as to receive surge protected and uninterruptible power from this system.  
         [0040]     In some embodiments, an uninterruptible power supply load monitoring circuit  660  is supplied with a display  380  that indicates the load being drawn from the power output connectors  140 . This display can be a set of light emitting diodes (LEDs) forming a bar graph, whereas, the right most LED may indicate a small load amount and the left most LED indicate a large load amount, so as the load increases, the LEDs light from right to left. The LEDs may be configured in an additive scheme and may be assigned linear power increments or logarithmic power increments. In other embodiments, the LEDs may be colored; perhaps the lower current LED being green, the medium current LED being yellow and the highest current LED being red. In alternate embodiments, an analog meter or digital readout display can be used instead of the LEDs or any other current indicator may be used.  
         [0041]     Being that the uninterruptible power supply and other modules housed within the metal chassis  105  may generate radio frequency noise, a conductive shield  240  shields the video protection circuits and connectors from this noise.  
         [0042]      FIG. 7  shows a schematic view  700  of an embodiment of a video protection module of the present invention. Video input connector  110  and video output connector  120  are connected to the video protection circuit board  420 . The video protection circuit  710  is shown mounted upon the back side of the video protection circuit board  420 . The video protection circuit  710  may be of various types known in the industry and include components such as resistors, capacitors, inductors, diodes and metal-oxide varistors (MOVs) for the purpose of allowing video signals to pass from the video input connector  110  to the video output connector  120  while suppressing power surges.  
         [0043]     Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in the same way for achieving the same result.  
         [0044]     It is believed that the system and method of the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.