A Complete Beginner's Guide to Distribution Amplifiers

The distribution amplifiers are analog/digital devices that enable the multiplexing of audio or video signals in uniform intensity. These devices have received utmost popularity in the video multiplexing operations in the video production and distribution industry, video security, and surveillance industry, etc. These distribution amplifiers are suitable for amplifying the audio or video signals being transmitted via coaxial copper cables, fiber optic cables, or HDMI cables.

However, in order to utilize these devices in an industrially or commercially operating network, it is essential to understand what exactly the video/audio amplifiers are, and how they work. Since there are multiple types of amplifiers available, it is important to select the appropriate one for the applications. This white paper introduces you to these amplifiers, their types, working principle, industrial significance and offers a few guidelines to select, install and troubleshoot the amplifiers.

An Overview of Distribution Amplifiers

The amplifiers are the devices that take video or audio signals as input, amplify their frequency to enhance quality, and then feed these signals to two or more outputs. These devices are responsible for the rectification of the audio or video signal strength, and uniform distribution of the signals. The signal distribution is done by the distribution amplifiers without the utilization of any ground loop or depletion or degradation of the media signal. The distribution amplifiers can transmit analog and/or digital signals. These amplifiers are also called distribution amp or DA.

According to the transmission potential of the amplifier, the two fundamental types of amplifiers are analog distribution amplifiers and digital distribution amplifiers.

• Analog Distribution Amplifiers: The analog distribution amplifiers take analog signals as input and amplify the signal to a higher frequency and further distribute it into multiple outputs. The analog distribution amps enhance the waveform by improving features like peak amplitude, fixed or variable signal strength, etc via amplification.
• Digital Distribution Amplifiers: The digital distribution amplifiers are the ones that amplify and distribute digital media signals. The digital distribution amps offer signal rectification to prevent signal buffering. Data path integrity, bit error, and transmission rate performance are maintained via re-clocking.

The following categories of distribution amplifiers are available based on the type of media being transferred.

• Audio Distribution Amplifiers: The audio distribution amp can be an analog or digital version of the amplifier. Conventionally, the audio signals from speakers, intercoms, etc are analog in nature, for certain audio signal amplification and bifurcation, the analog audio distribution amps are suitable. However, when it comes to audio distribution multimedia signal transmission, the audio waves are converted into digital format (recorded samples of audio frequency at a specific rate). The digital audio is distributed using digital audio amps.
• Video Distribution Amplifiers: The video distribution amplifiers are distinguished based on the video transmission standards. The following are a few important types based on the standards.
  • HD-CVI Interface: HD-CVI stands for high definition composite video interface. This model of the DA features digitalized composite video signal amplification and distribution.
  • HD-TVI Interface: HD-TVI stands for high definition transport video interface. It enables the amplification and distribution of analog video signals via coax cables at a faster rate. TVI features a scope for the digitization of transport video signals.
  • AHD: AHD stands for analog high definition. AHD enables the transmission of high-definition analog signals. There is negligible scope for the digitization of signals in AHD.
  • HD-SDI:  HD-SDI stands for high definition serial digital interface. HD-SDI enables the transmission of high-definition digital video signal transmission. It features amplification and distribution of signals up to 1080 pixels over a coaxial cable.
  • HDMI- DA: HDMI stands for high definition multimedia interface. It enables the transmission of compressed or uncompressed digital audio and/or video signals. These devices operate in compliance with high-bandwidth digital content protection (HDCP) protocol, which ensures the security of signals being amplified and multiplexed.

Significance of Distribution Amplifiers in the Fiber Optics Communication Networks/ HDMI Distribution

As said earlier, distribution amps are highly popular in industrial video and audio transmission networks. However, the following are a few factors that make these devices highly significant.

• The distribution amps are essential when there is only one source of signal but the recipients are multiple. An optional device called a splitter can be utilized to distribute the signals, however, the splitter may lack several capabilities. While distributing the signals, it is essential to maintain the data frequency of all distributed signals in uniform strength. The low strength signals can affect the overall performance of the network. Therefore, it is essential to utilize a distribution amplifier that will amplify the frequency and distribute the signal to multiple devices without depleting the quality of audio or video signals.
• When the analog/digital signal is split electronically, the resulting loss must be compensated by the distributing device in order to maintain the signal quality. In the analog signal distribution, the distributing amp compensates for the resulting loss in the form of amplitude or voltage. Whereas, during digital signal distribution, the resulting loss is compensated in the waveform by the distributing amps. This way, signal buffering, attenuation, data loss, video frame loss, etc are prevented.
• The distribution amps are proven highly significant in the media production and outsourcing industry. However, the common industrial applications of distribution amplifiers are listed below.
  • Television and Multimedia Production Facilities, and Post Production Operations
  • Video Surveillance Networks- CCTV
  • Cable Connection Networks
  • Satellite Communications
  • Video Multiplexing and Channel Switching
  • RF Signal Processing

Since DA is such a significant device in networking applications, let us discuss how to select an appropriate one.

Guidelines to Select Distribution Amplifiers

Utilizing a distribution amp only gives optimum results when selected with the appropriate specification. Industrial signal transmission operations are versatile and therefore demand specific features and signal distribution capabilities from the integrated devices. Owing to certain requirements, the distributing amp must be selected by considering certain crucial factors. The following factors must be considered while selecting the distribution amps for specific operations.

• Input to Output Port Ratio: The distribution amplifier has one input port and multiple output ports. However, one input port can be only connected to one recipient device. However, the output ports must be enough to connect all the recipient devices. The number of input ports to the output port is the port ratio that must be considered while selecting the DA.  In general, there are 1-port, 2-port, 4-port, 8-port, and 16-port distribution amps are available. However, these devices can be custom designed for challenging applications. Based on the number of output ports the signal strength is distributed in uniform frequencies. For example: In 2-port DA, 50-50% of signal distribution takes place to output, whereas for 4-port DA, 25% of amplified signal strength goes to each output port.
• Return Path Capacity: The distribution amplifier is a two-way communication device. Although the forward transmission from the input port to the output ports is prominently utilized, the return transmission is also of utmost importance. On occasions like abrupt termination from receiving devices, or network failure, the data loss must be prevented by sending the signals back to the source. To perform the reverse transmission, the return path is activated in the distribution amp. However, the return signal capacity of the device must be enough to sustain return transmission. Thus, the return path capacity must be checked while selecting the device.
• Amplifier Gain: Amplifier gain is the amount of amplification in the signals. Generally, the distribution amplifiers are designed for +15dB of amplifier gain per cycle of amplification. However, if the amplification gain is negative, for example, -10dB, it is considered to be signal loss itself. Less amount of amplifier gain would cause higher data loss, attenuation, and loss of data frames. This is why, while selecting a distribution amp, it is essential to look for a higher amount of amplifier gain.
• Power Requirements: The distribution amplifiers are electrically powered devices. Advanced distribution amps have a scope for using a power inserter. The power inserter is an external device that back feeds the power to the distribution amp via one of the output ports’ return-path. The use of a power inserter helps in powering the distribution amp in the locations where an absence of a direct power source is seen. Considering power requirements and availability of power sources, the distribution amps with power inserter or frontline power input should be chosen.
• Third-Party Device Compatibility: Since the DA is integrated into a fiber optics, copper-cable, or hybrid communication network along with different devices. These third-party devices may or may not have direct communication links with the DA but the compatibility of devices in an integrated circuit makes an impact on the overall performance of the network. Therefore, the compatibility of the distribution amplifier with other devices like media converters, network switches, fiber optics cables, etc must be checked before installation.
• Installation Requirements: The installation requirements of the distribution amplifiers often differ according to the environmental conditions and length of transmission from one DA to another DA or a third-party device. Also, the mounting or coupling mechanisms, compatibility in harsh environmental conditions, etc are the factors that contribute to the installation requirements of the DAs. Therefore, their operating conditions and specific application requirements must be carefully analyzed.

Now that installation is an important factor of consideration in the selection of an appropriate distribution amplifier, let us discuss the installation procedures for complete understanding.

Installation Procedure for the Distribution Amplifiers

The installation process of video distribution amplifiers includes the following steps.

• Turn off the network power supply.
• Decide the location of a distribution amplifier. Ensure that the location of the device is nearby the antenna or CATV cable connections.
• Mount the DA at the decided location. The mounting process may differ based on the mounting mechanism of the device. Often snap-latch or BNC connector type of mounting mechanisms are available in these devices.
• Check for the input port. The input port is located at the top left corner of the amplifier box. Connect a 75-ohm coax cable to an input port.
• Locate the return path port which is the RF IN port and plug in the CATV cable to the RF IN port.
• Connect the output port of the recipient devices like display units, multimedia player units, television sets, etc. However, if the distance between the recipient device and DA is longer, then it is convenient to integrate a fiber optic cable between both devices. Fiber optics cables offer negligible data loss, and amplified multimedia signal transmission at higher speed and higher bandwidth.

Note: In the case of HDMI-compliant display units, HDMI-distribution amplifiers are essential to be used.

• Ensure to connect each output port of the DA with one of the recipient devices. If there are any additional or open output ports, terminate those with F-type connectors. This prevents any signal leakage via open outlets.
• As the final step, turn on the main power supply and ensure the LED on the amplifier box is illuminated as an indication of active operation.

All the above-mentioned steps will suffice for the indoor installation of video distribution amplifiers. However, for outdoor installation, it is essential to safeguard the DA unit with water seals, weather-protective housing jackets, etc in order to prevent damage due to harsh environmental conditions.

Caution:

The installation of video DA units possess the threat of electrocution due to the possibility of residual electric current in the network, even after termination of the main power supply. To prevent certain hazards, it is essential to get these services from experts and perform the installation meticulously and safely.

Conclusion

Distribution amplifiers are devices being extensively utilized for video/audio signal amplification and distribution operations. Multimedia streaming, CCTV surveillance, etc are some operations that are highly reliant on these devices. In this white paper, the introductory discussion over distribution amplifiers and their types is done. The discussion is taken forward with the significance of distribution amps in multiple industries. Finally, considering the importance of selecting an appropriate DA unit for the application, the selection guidelines are listed in the white paper. The installation must be performed by the experts in order to prevent possible hazards, also, the quality of the DA may directly impact the performance of the overall communication network. Therefore, it is important to verify the quality of distribution amplifiers while buying. VERSITRON ensures the quality of their video distribution amps by implementing a smart design, robust construction, and MSA-compliant performance parameters. The company provides video distribution amplifiers in various configurations, including 16 video inputs and 32 video outputs distribution amplifiers (VDA1632A), 16 video inputs and 48 video outputs amplifiers (VDA1648A), 16 video inputs and 64 video outputs amplifiers (VDA1664A). These products can work with high-definition security cameras and other video sources using appropriate connections. Contact us to know more about VERSITRON's video distribution amplifiers.