Posts Tagged ‘ digital video system ’

Passive Video Balun

Friday, July 8th, 2011

If you would rather use Cat5E instead of RG59 cable, it’s likely that somewhere along the way you will need a passive video balun.  Security Camera King carries a full line of baluns both active and passive.  Passive video baluns help prevent the degradation of the radio frequency signal over cable.

A balun is really a specific type of transformer that can convert electrical signals that are balance about ground (also known as differential) to signals that are unbalanced (single ended) and vice versa.  The name “Balun” comes from two words, BAL(ance) and UN(balance).

For those of us that are not electrical engineers, another way to put it is that passive video baluns can boost signal strength and help your system make a transition to one type of cable to another.  For example, most cable used in the digital video security industry is RG59 coaxial cable.   This is an excellent cable for the job, however RG59 only has a working distance of about 600 feet before the signal starts to degrade causing poor video quality.

Using a passive video balun, the signal can be changed at the connection source from RG59 to CaT5E.  This is done because Cat5E is less expensive for one thing, secondly it’s easy to pull when installing it, it’s generally less expensive than RG59, and a passive video balun and Cat5E can carry a signal further than RG59 cable, usually about 1,000 to 1,200 feet.

In addition, if you do use Cat5E cable instead or RG59 you will have multiple pairs of wires at your disposal.  RG59 basically has a solid copper core wire insulated with plastic and then a metal shield (in essences the second wire) which is then covered by the cable cover (usually some type of plastic).  A digital video camera uses both of those wires the copper core and the outer shield to transmit its signals.

However, by using a passive video balun with Cat5E cable you have access to 8 (4 pairs) of (usually) 22 gauge wire.  This allows you to use just one Cat5E cable instead of 4 RG59 cables for 4 security cameras.

Many people would say they’ve never seen a balun before, but chances are they have.  Some older model TVs came equipped with a cable TV type plug and no antenna connection.  Usually, the RG59 type cable has 75 ohms of impedance.  An antenna was often 300 ohms of impedance.  An “adapter” often came with the TV with a male cable TV type plug on one end, and two screw connections on the other end to connect to an antenna.  That adapter is actually a balun, and it’s used to balance the impedance differential between the TV outlet and the antenna.

Before going any further, now would be a good time to address the “passive” in passive video balun.   Baluns may be passive or active.  An active video balun is much like the passive video balun with one distinction:  The active video balun requires power.  Usually, most active baluns use 12 VDC, the same type of power that the digital video system uses for the cameras.

Active video baluns, depending on the type, etc. like the one used in our example above of the passive balun that got 1,000 – 1,200 foot range, would be capable of boosting the signal on Cat5E upwards to a length of up to 4,000 – 5,000 feet.

Security Camera King offers a wide variety of passive video baluns to suit your needs.  Below is a partial list of our available baluns and a short description of each:

  • Product# BALUN-P.  Passive video balun with BNC connector on one side and Cat5E connector (RJ45) on the other;
  • Product# SVU-PR8.  8 channel passive CCTV receiver hub with female BNC outputs.
  • Product# BALUN-V.  Single channel passive video balun with video and power.  This balun is not powered, it truly is passive.  The power connection provided is for continuing your power supply past the balun by using one pair of wires from the Cat5E cable.  Saves time so you don’t have to cable separate power supply wires.

This should give you a good idea of what passive video baluns are and what they do.  If you have any additional questions please contact one of our security experts.


Security Camera CCD

Tuesday, June 21st, 2011

We are asked quite often about the security camera CCD (Charged Coupled Device) and the CMOS or Complementary Metal Oxide Semiconductor.  In the following article we’ll discuss how a digital video system actually works and what importance a security camera CCD has within this system.

First let’s describe a digital video security and surveillance system.  It normally consists of three components; the camera(s), the Digital Video Recorder, and a monitor(s).  The camera’s function in this system is to capture a video image created by light reflectance and transform it into an electronic image based on electricity.  Both live and recorded material is played back by the DVR and may be seen by watching the monitor.

So now that we have a general idea of what each component does, let’s talk specifically about the camera and the security camera CCD.

A digital video camera works by using a combination of mechanical (lenses) and electronic (Integrated Circuit or IC chips and printed boards).  Whatever direction the camera may be pointed in, the area that you will see as a point of view from the camera is called the camera’s field of view.  The field of view is the specific area that will constitute the video image.

The field of view can be made larger or smaller depending on the focal length of the lens.  A standard lens has one focal length and therefore on field of view.  Varifocal lenses can vary their focal length (either manually or remotely).  The field of view contains objects that reflect light.  This reflected light is captured by the lens and when in focus, the lens focuses the reflected light on a sensor chip which is usually only 1/4 to 1/3 inches square.

This sensor chip, in our case, is the security camera CCD.  As the focused light strikes the security camera CCD, tiny pixels on the sensor emit a very small but measurable electric impulse.  Their may be more than one CCD and their maybe the use of one or more filters involved as well.

Once the light strikes the security camera CCD, the CCD gives off it’s electrical pulses and this are measured and interpreted by the analog to digital processor IC chip.  This is when the video image becomes digital.  As the processing continues in the camera, the camera’s Digital Signal Processor or DSP, in essence another IC chip, makes adjustments to brightness, color intensity, contrast, etc. to make sure the video image is of the highest quality.

Once the video image information, now binary or digital data is sent to the DVR the DVR stores it or plays it live.  Either the camera or the DVR compiles the binary data and creates a digital video file out of it.   These digital video files are the same type of digital video files that can be watched on a personal computer.

The security camera CCD (and the CMOS) has a unique feature about it that makes it even more versatile.  The CCD inherently can also create video images using on infrared light.  Infrared light is invisible to the human eye, so this makes for a very powerful, useful security device.  Most night time infrared cameras have an array of Infrared producing Light Emitting Diodes or IR LEDs that are arranged around the lens of the camera.   The human eye cannot see their light, but to the CCD, they work like using a floodlight.

In addition to the array of LED’s around the camera lens, IR LED illuminators may also be used.   Illuminators are just a group of more IR LEDs to add more light to the picture.  Some illuminators boast IR ranges of as much as 300 feet when using the illuminator along with the camera’s own lights.

Incidentally, since this type of video construction is done with only IR light, the image will be in either black and white or monochromatic.  But very seldom will the detail or resolution degrade so the IR video image is as good of quality as the day time color versions.

Security Camera King has a large variety of security camera CCD cameras and systems.  Be sure to check the “Specification” tab when looking at a camera that you may be considering to purchase to make sure that the camera gets the proper night time range that you will need.


Security Camera Cables

Friday, March 4th, 2011

If you have a “wired” digital video system, you’ll want to make sure you have the correct security camera cables for it.  In this article we’ll take a look at the most common type of security camera cable and its connectors.

Digital video security cameras generally require two types of cable; one for video transmission of the camera to the DVR (Digital Video Recorder) and one for the power supply for the camera from a power supply source.

The most common security camera cable used today is the RG-59/U.  This is a coaxial cable designed specifically for low-power video signals.   Historically speaking, the name of the cable originates from the U.S. military.  RG-59 designated the type of cable and the “U” stood for general utility use.  However, the “RG” (which stood for “Radio, General”) component is no longer part of military standards, however the name use has remained, generally without the “/U” designation.

RG-59 security camera cable has a unique characteristic that makes it a good match for use with video transmissions.  It has the same impedance as an antenna, such as the “rabbit ears” type that was used on televisions.  This impedance of 75 ohms makes the cable a good choice for radio frequency transmissions for televisions, DVRs, and security camera video.  RG-59 is smaller than typical cable television cable, RG-6, and is therefore less obtrusive and easier to manipulate.

However, RG-59 has a tendency toward high-frequency losses over long distances (greater than RG-6 for example) but 750 feet seems to be a generally agreed upon length before significant losses appear.  These can also be corrected with drop amplifiers or active (powered) baluns to boost signals.  For most security camera systems applications, RG-59 coaxial cable works well.

The RG-59 security camera cable consists of an outer plastic sheath (the colored cover or jacket of the cable), followed by a copper braid shield (it looks like a mesh or netting of fine wire), underneath which is an inner dielectric insulator (often looks like a milky white thick plastic material somewhat like a drinking straw) that contains a copper-plated or solid copper (better performance) center wire core.

RG-59 cable is usually fitted with one of three different types of connector; F connectors (used most commonly for cable television applications), RCA plugs (often used by DVD players), and BNC connectors.  By far the most common type of security camera cable connector is the BNC.

The BNC connector provides a means of connection for both the shield and core of the cable.  The connector has “male” and “female” plug types that when inserted together and twisted properly, stay locked together.  In fact “BNC” stands for the bayonet like locking mechanism (B), and Paul Neill (N) and Carl Concelman (C) it’s inventors.

Security Camera King offers three different types of BNC connectors based on how they attach to the RG-59 cable.  Connectors are fastened to the security camera cables either by twisting on, crimping, or compression.  Twisting is the simplest and requires no additional tools once the wire is stripped and trimmed.  Crimping, when done properly, generally holds the connector to the cable better but requires the use of a crimping tool.  The best connection that provides the greatest strength is the compression BNC and it requires a compression tool.

Security cameras also require a power supply cable.  This is normally standard 18 gauge copper wire with plastic insulation.  The power for most security cameras is low voltage DC current of 12 volts or low voltage AC current of only 24 volts and this wire is suitable for carrying the power supply of either.  The power supply cable that terminates at the security camera end usually does so using either screw terminals for each wire (often for AC) or a 2.5 mm female type power plug (often for DC) with a positive center.

Security Camera King offers complete security camera systems that include security camera cables for both power and video transmission.  We offer pre-cut lengths of video and power supply cable with connectors already installed for “plug n play” use.

For applications with differing distances of cameras from the DVR, we offer bulk Siamese RG-59/18-2 cable with twist-on connectors.  This cable consists of both the RG-59 video transmission cable and the 18 gauge 2-wire power supply cable.  One cable means one run per camera saving you time and work.

There also offer other types of less common security camera cables.  Check our Web catalog for more information.


Security Camera Software

Friday, November 19th, 2010

Security camera software is the glue that ties together digital video cameras and Personal Computers (PCs) or Macintosh Computers (Macs) as well as Digital Video Recorder (DVR) units for standalone systems. It’s also the heart of remote DVR monitoring applications (Apps) that allows your smartphone to access your video security system. It essence it provides the programming that allows you to control the camera, monitor the camera, and record the digital video files.

There are many types of security camera software. Perhaps the simplest to use is a typical web browser such as Internet Explorer, Firefox Mozilla, Google Chrome and others. For digital video security cameras and DVRs that are IP (Internet Protocol) ready, a web browser may be all that is needed to control, monitor, and record digital video security images.

Although it may be difficult to describe what security camera software is, we can easily describe what it isn’t. Security Camera Software is not firmware. Firmware is basically the drivers and internal commands that a device needs to communicate with processors and other devices. Firmware is device and manufacturer specific.

Security camera software is not Operating System (OS) software. Operating systems like Windows, Linux, Mac, and others provide the basis for central communication between devices, processors, and users. OS software is what makes a computer system work.

So where does that leave us with security camera software? As stated earlier it could be considered as a web browser, but typically security camera software is specific programming that is designed to operate a digital video security system. We can list the types of security camera software based on how they are designed to work. Security camera software can be:

• Designed to provide the control, monitoring and recording of security cameras and DVRs;
• Designed to allow PCs and Macs to provide the control, monitoring, and recording of security cameras when used in conjunction with a security video PCI card;
• Designed to provide the control, monitoring and recording of security cameras and DVRs that may be networked using the Internet (IP ready);
• As mentioned earlier, designed as Apps for Smartphones to allow them to monitor IP ready cameras; and
• Designed to integrate a variety of digital video capture devices such as webcams, netcams (or IP ready cams), computer PCI capture cards and computers to create a digital video security system.

The first type on our list is software that is normally provided when you purchase a standalone digital video security system with a DVR. The manufacturer of the DVR or the Cameras (or both) may provide the software that is normally installed on the DVR unit. This software is used to control camera functions such as Pan-Tilt-Zoom (PTZ) functions and timers that turn the cameras on and off.

The second type of security camera software on our list works with computers that use a PCI card. There are some digital video security systems that are specifically designed to work with your computer. For example Geovision brand PCI DVR cards provide inputs for multiple security cameras that connect to your computer. This system uses your computer’s hard drive as the DVR. The software that accompanies this card that allows the computer to control the cameras and store the digital video files is a type of security camera software.

Our third type applies specifically to IP ready digital video cameras, DVRs and servers, and systems. The software is normally produced by the manufacturer of the security system and is designed to allow a computer to control, monitor, and record security video using the network. As mentioned at the beginning of this article, it may be something as simple as a web browser, but it can also be a proprietary program produced by the security equipment manufacturer that is used to coordinate the video security system’s functions. These may also be in the form of browser plug-ins such as ActiveX subroutines that must be installed in the browser before it is used with the system.

The fourth type of security camera software is Smartphone Apps which we have already described.

The fifth and final type of security camera software allows you to use a variety of video capture devices (such as webcams or capture cards) in conjunction with your computer to create your own digital video system. While this does not create the ideal video security system, it does save money by allowing you to use equipment you have already purchased to create a digital video system.