What is the use of a video modulator.
What is the use of a video modulator.
Video signal modulator
Based on the general definition, video signal modulatoris a device that changes the parameters of the flowing signal in accordance with changes in the transmitted information signal. Video signal modulator converts both harmonic and pulse oscillations. According to the controlled parameters, the video modulator can be presented in several varieties: amplitude, frequency, phase, quadrature, single-sideband. Depending on the carrier signal, the modulation type can be mixed. A video modulator is one of the components of transmitting communication devices that transmit images. Modulators that convert direct voltages into alternating voltages are used in direct current amplifiers and null-organs that operate on the modulation-demodulation principle to eliminate zero drift and increase the sensitivity of analog computing devices. Devices that operate on this principle are called modems.
Video modulatordecimeter is used to transfer the video signal of the image and sound to the frequency of an arbitrarily selected television channel. It can be used for various purposes: as part of a security video surveillance system, a local cable television system. Video modulator from most manufacturers is characterized by the ability to operate continuously. It should be remembered that the device is under life-threatening voltage, so installation must be carried out in strict compliance with safety rules.
Installing a video signal modulator, you should place the device in the place of its intended location. There is a switch on the cover of the device, with which you should set the channel number code in accordance with the code table. Next, you should connect the output cable to the connector and to the receiver input. If you need to mix the modulator signal into the television network with existing TV channels, then the cable coming from the antenna should be connected to the connector. In this case, you should pay attention to the fact that the carrier frequencies of the programs in the system do not coincide with the carrier frequency of the modulator.
TV modulators
Television modulatorsare designed to connect a VCR or video camera to a TV via a high-frequency channel. Most VCRs have a high-frequency output, but in some models of VCRs and TVs, the intermediate frequency of the sound does not correspond to our standard, so when connected via a high frequency, there is no sound in the TV.
TV modulators, as a rule, operate in the UHF range, which requires the presence of an SKD block in the TV. This modulator-transmitter forms a complete television signal at high and low frequencies. The intermediate frequency of the sound is set by a potentiometer. TV modulatorsallow you to build a video surveillance system based on an existing or specially created television cable network. These devices are designed to convert a full color video signal and an audio signal into a television radio signal. All types of radio signals are supported. At the same time, frequency multiplexing becomes possible — transmitting signals from several video cameras via one radio frequency cable. Installation of a cable network with such a device also becomes easier: instead of laying separate cables from each video camera to the television surveillance post, it is enough to lay one common radio frequency cable or use an existing television cable network. Television modulators are suitable for interfacing with devices of security television and surveillance systems: switches, quadrators, monitors, video recording devices. The camera is powered through a modulator from a common power source, which must be designed for the total current consumption.