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Injecting CCTV signals into SMATV antenna systems. The conversion of baseband audio-video (A/V) signals into radio frequency (RF) channels is called modulation. This process allows for distributing the signals coming from all kinds of sources, such as computers, DVD/Blu-ray players, security cameras etc. through antenna systems. Nowadays, the device used for this purpose (modulator) is usually equipped with HDMI input(s). The output RF signal injected into the antenna system is available in the distribution network as additional TV channel (DVB-T multiplex) that can be received by any suitable television connected to the RF distribution network.
Digital modulator R86700 is used in integrated CCTV/SAT systems, it can be used for transmitting signals from a DVR or NVR to multiple TV receivers via coaxial cable. The digital modulator R86700 enables conversion of the incoming Full HD signal (1920x1080-60p) received via HDMI to the DVB-T COFDM standard. It is a perfect alternative for systems based on HDMI splitters and cables.
HDMI-DVB-T modulator, R86700.
DVB-T modulators supporting HDCP protocol (such as R86700) can also be used to provide a channel in the TV system with a program set e.g. on a satellite set-top-box – e.g. to use in bedroom the capability of the set-top-box located in the living room.
The terrestrial antennas should be chosen according to local reception conditions. Some specific examples are presented in the article Selection of Terrestrial TV Antennas.
In the above example, the Signal R86700 digital modulator is connected to the DVR's HDMI output and then modulated to DVB-T. The antenna set consists of: the A2670, A0710 and A0221 antennas. Any other configuration of the set of antennas working in FM, UHF, VHF bands is of course possible. Masthead antenna amplifier DVB-T MA080L FM-VHFIII-UHF TERRA R82022 has three inputs: FM (88-108 MHz), VHFIII (174-230 MHz), and UHF (470-790 MHz), and each path has a separate gain adjustment. The UHF path has built-in LTE 800 filter. The MRP-508 R68508 multiswitch is equipped with 12 V DC switch in the antenna path that allows to power the MA080L R82022 amplifier. Signals from the modulator and antennas are summed with the use of RI-2/1 F E2094 combiner/ induction splitter which transmits DC voltage from 1 output to the input.
