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The fiber links provide a transparent connection between the satellite antenna with its up/down-converters, and the control room modems. The use of optical fiber overcomes problems inherent in copper based solutions including electrical interference, path length and electrical safety isolation. A typical RF-over-fiber system consists of an optical transmitter, optical receiver and the optical fibre. They use intensity modulation, in which the RF signal is used to directly modulate the intensity of a light source e.g. a laser diode. This technique removes the need for any additional frequency conversion or digital conversion, and results in a very low noise and low distortion transmission path. The PPM fiber links offer exceptionally low phase noise performance, which makes them suitable for narrowband schemes. Intensity modulation also makes the links suitable for any modulation format, and they are, therefore, inherently future proof. PPM's links are designed to be used with little or know previous knowledge of optical fiber installation and use. In addition to providing the fiber optic transmitters and receivers, PPM can supply pre-terminated fiber optic cables for internal, external and riser applications. These ruggedised cable assemblies are delivered complete with pulling boots and installation instructions, removing the need for on-site fusion splicing and connector termination. PPM's SatCom product range includes a large number of product variants to suit many different applications. Our cost-effective Fabry Perot laser products are ideal for short haul links of up to 2km (depending upon your exact link budget). For longer haul links of up to 20-40km, or where low noise or wide dynamic range is required, PPM offers 1310nm wavelength DFB laser based products. For even longer haul links, or when there is the need to combine two or more channels on a single optical fibre, 1550nm wavelength DFB products are available. In some applications, it is necessary to combine multiple RF channels for transmission over a single optical fibre. In this case, PPM's Course Wavelength Division Multiplexing (CWDM) solution enables you to specify transmitters containing different wavelength laser diodes. The use of a CDWM multiplexer module combines these onto a single optical fiber. At the far end, a CWDM de-multiplexer separates out the different wavelengths and applies them to different receivers. The CWDM technique can be a very cost-effective solution - particularly over long path lengths. High levels of redundancy are a common requirement of satellite data communication systems. PPM's product range includes RF splitters, RF switches and alarm monitoring modules to enable system integrators to implement 1+1 or 1+N redundant systems. Manual gain control receiver options are available, which enable installers to fine tune signal levels. This is particularly useful in matching the alternate paths in redundancy systems. The best dynamic range in the industry means that PPM's links offer superb performance over a wide range of input signal levels, without the need for time-consuming and expensive set-up procedures. A comprehensive alarm scheme enables operators to constantly monitor the status of the transmission equipment via the M&C system. ViaLite modules are available in several physical formats. The 19" rack case, accommodates upto 8 plug-in modules in addition to two dual-redundant power supplies. The following items are amongst the large number of possible plug-in module types:
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sales@ppm.co.uk +44 1793 784389 ©Pulse Power & Measurement Ltd 2008 | ||||||
