Currently, large-screen TVs have become more affordable, and cameras have learned to broadcast a high-definition picture - as a result, the image on the screen has good detail.That's just the connection to the TV is not simplified.Surveillance cameras can be of two types: analog HD and IP-enabled.Neither one nor the other can be directly connected to the TV.The cameras are connected either to an AHD-HDMI converter or to a DVR.In any case, the output of such a device must have an HDMI connector that connects to the TV.This is where problems appear.To distribute the signal to multiple TVs, you can use an HDMI splitter.But it has a limitation on the number of outputs, distance (usually tens of meters), it is necessary to lay additional cables.In addition, many users find it inconvenient to have to switch to the HDMI input mode to view the live feed from the camera.To be able to view according to the old principle - when the image from the camera is visible on a certain channel - it is necessary to use a digital modulator.How to choose the right type of modulator?Commercially available modulators are of the following types: with support for the DVB-T standard, DVB-C standard and combined (DVB-T + DVB-C).DVB-T modulators form an outdated broadcasting standard signal.However, this does not prevent the use of this signal in the cable.This signal will be received by all modern TVs.The same can be said about DVB-C modulators.Universal modulators can generate a signal of both standards.When choosing a modulator standard for generating your own television signal, it is advisable to choose the same standard (air or cable) in which television programs are received.This makes it possible to select your channel in the same way as selecting a TV program and see it in the program list.With different standards of the modulator and television broadcasting, more actions are required to select the reception mode (cable or antenna), which is difficult for the average user.I want to talk about my personal experience of mixing the signal from the DVR into a television signal distribution system for six TVs.Television programs were received from cable television in the DVB-C standard.The budget modulator Terra MHD003 was chosen.This modulator has an HDMI input and generates a cable standard digital television signal at the output.The Dune media player was used as a high-definition source for the first turn on and setup.The signal parameters were left by default: QAM64 modulation, transmission rate 6875 Kfs/s, output signal level -15dB, only the output channel number was changed to 36 (free in this cable network).