Selecting the Right Distribution Amplifier
What is a Distribution Amplifier?
Distribution Amplifiers, or DAs, are used to divide a single video source or audio source and duplicate it into two or more identical copies of the original signal. DAs can be designed to support digital, analog, or a combination of digital and analog signal types.
- Digital DAs usually include signal buffering and reclocking to maintain data path integrity and bit error rate performance.
- Analog DAs provide signal amplification and enhancement features such as fixed or variable peaking and gain.
Why are Distribution Amplifiers Needed?
Whether the application is digital, analog, or a mix of formats, a source’s signal originates at a pre-defined level of signal drive capability and is commonly designed to support a single destination device such as a flat panel display or projector. If a signal is split electronically, the splitting device must provide compensation for the resulting loss in waveform for digital devices or amplitude/voltage for an analog device. Additionally, long cable runs, low quality cables, and source devices with poor signal output can negatively affect system performance. A DA ensures reliable source signal delivery to all connected destinations.
In a digital AV system, data parameters must be met. If too many devices are added to a single digital output, the signal level can fall below the normal operating threshold, referred to as the “digital cliff”, causing data delivery to fail. Digital video characteristics include synchronous communication, signal swing, and clock period. A digital signal must transition at specific intervals, as determined by the clock, with recognizable differences between high and low values. The clock period is the minimum allowable time between transitions.
For example, signal reflection in a low quality digital cable can cause distorted signal transitions that are misinterpreted by a receiver as data. This can result in the loss of synchronization with the source or cause the display of erroneous information. A DA that supports digital technologies is designed to compensate the signal to meet these parameters.
In analog systems, the rise and fall times of the leading and trailing edges for both low and high resolution source signals may become distorted or degraded, affecting the high frequency portion of the signal that carries video and sharpness or detail information. The signal may require video amplification and peaking to compensate for the voltage losses and high frequency attenuation that normally occur in long cable runs or with poor quality analog source signals.
How are they used?
Distribution amplifiers are ideal for use in a wide range of professional AV environments, including classrooms, lecture halls, courtrooms, museum exhibits, and corporate meeting spaces.
In the example below, a 4K Media Player is connected to the input of the Extron DA4 HD 4K PLUS distribution amplifier. The DA4 HD 4K PLUS is sending digital signals to four high definition displays.
A DA can include technologies that ease integration with a wide range of applications. For example, the DA4 HD 4K PLUS shown in the above diagram features two Extron-exclusive technologies: EDID Minder® and Key Minder®. EDID Minder automatically manages EDID communication between all connected devices. By maintaining continuous EDID communication with the source, EDID Minder ensures that it powers up properly and reliably sends content to the destinations. For HDMI signals with protected content, Key Minder continuously authenticates HDCP encryption between all devices, ensuring the simultaneous distribution of source content for display.
Choosing a Distribution Amplifier
To select the right Distribution Amplifier for a specific application, identify the key requirements necessary to support the design. Answer the following questions before selecting a DA:
- What signal type will be distributed?
- How many outputs are required?
- How far is the signal being run?
- How does the DA need to be mounted?
- What are your space requirements?
Categories
Extron offers a variety of DAs designed to support most digital and analog signal formats. All Extron DAs feature fully buffered outputs to retain the integrity and level of the original signal. When selecting a DA, first define your signal and system requirements as described in the previous section. Then, pick the product category that best fits your needs.
Fiber Optic Distribution Amplifiers
Extron Fiber Optic distribution amplifiers enable distribution and long haul transmission of AV and RS‑232 control signals over fiber optic cable. They provide active, individually isolated optical outputs for distribution to FOX Series fiber optic receivers, switchers, or matrix switchers. Extron Fiber Optic Distribution Amplifiers support higher data rates for distribution of DVI‑D, multi-rate SDI, RGBHV, HD component, and standard definition video.
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HDMI Distribution Amplifiers
Extron HDMI distribution amplifiers are engineered for reliable operation in commercial AV applications. They are HDCP compliant and equipped with two Extron-exclusive technologies: EDID Minder, which automatically manages EDID communication between connected devices, and Key Minder, which continuously authenticates HDCP encryption. Extron HDMI distribution amplifiers also include other integration-friendly features such as automatic input cable equalization, automatic color bit depth management, and +5 VDC, 250 mA power on each output. Extron HDMI distribution amplifiers with DTP twisted pair outputs provide the additional capability of extending HDMI plus control and analog audio up to 330 feet (100 meters) over shielded CATx cable.
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DVI Distribution Amplifiers
Extron distribution amplifiers for single-link DVI distribute equalized digital video signals to multiple devices. They are compatible with computer resolutions up to 1920x1200 @ 60 Hz, including HDTV 1080p/60. EDID Minder, an Extron-exclusive technology, which automatically manages EDID communication between connected devices, is available on most models.
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DisplayPort Distribution Amplifiers
Extron DisplayPort distribution amplifiers are HDCP compliant, and include integration-friendly features such as EDID Minder, Key Minder, input cable equalization, and selectable output muting. Additionally, these DAs provide dual-mode DisplayPort support, allowing source signals to be sent to HDMI, DVI, or VGA display devices with appropriate adapters.
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HD-SDI, 3G-SDI & 12G‑SDI Distribution Amplifiers
HD-SDI, 3G-SDI & 12G-SDI distribution amplifiers support multi-rate SDI digital video signals up to 11.88 Gbps. They feature input cable equalization, output reclocking, and automatically recognize and adapt to common serial digital video signals that comply with SMPTE and ITU standards, including SMPTE 2082, ITU‑RBT.601 and ITU‑RBT.1120.
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VGA and RGB Distribution Amplifiers
Computer and RGB distribution amplifiers support the various types of analog VGA and workstation-style connection schemes, such as RGBHV, RGBS, and RGsB. Most models feature gain and peaking controls for maintaining signal integrity over long cable runs. This type of distribution amplifier can also be used to distribute composite video, S‑video, and analog component video signals. RGB DAs can accept VGA‑QXGA video using the appropriate adapter.
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Audio/Video Distribution Amplifiers
AV distribution amplifiers are available in a variety of models for composite video, S‑video, component video, serial digital video, and stereo audio. Some Extron DAs combine more than one DA in a single enclosure. For example, the Extron DA 12V/6V Dual EQ contains two one-input, six-output composite video DAs. Only one internal power supply is used to power both DAs. With two DAs built into one rack-mountable enclosure, the dual DAs offer space savings, heat reduction, with pricing typically below that of two separate DAs. For small system needs or cost-sensitive applications, MDA Series Distribution Amplifiers feature compact, quarter-rack width enclosures with flexible mounting and power options. Extron MDA DAs may be easily and economically integrated into new and existing AV system designs.