There are two types of the modulator used to convert and send a signal. Analog and Digital Modulator both have their specific functions and usage. In a Digital Modulator such as Digital RF Modulator, In a Digital Modulator, there are three different types of Modulations ASK or Amplitude Shift Key, FSK or Frequency Shift Key and PSK or Phase Shift Key.
Types of Modulations
To understand Digital Modulation, Imagine you have a digital data in the form of a pulse going from 1 to 0 and back to 1 again. In ASK if we have a 1 we send our carrier signal and when we have 0 we don’t send it. You can imagine it as a switch which switches on or sends the signal when a 1 comes and switches off when a zero comes. In PSK modulation, when we have a 1 we have zero phase, but when a zero comes instead of stopping the signal we shift it with 180 degrees and back to phase zero when another one comes. In FSK modulation use two different frequencies instead of two different phases. So when 1 comes we send a frequency F1 and when zero comes we send F2.
The ASK technique is mainly used to transmit digital data over optical fiber. FSK signal can be transmitted via telephone lines, fiber optics or wireless media. FSK is commonly used for caller ID and remote metering applications. PSK is typically applied in wireless local area networks (WLAN), Bluetooth technology and radio frequency identification.
We are not limited by these three types of modulations, these are the only ones commonly used. There are few other types such as in Amplitude Modulation there are two types of Modulations such as PAM and QAM and in Phase Modulation, you have two more types in addition to PSK, the second one is DPSK and the third is called OPSK. The types of modulations go on and on.
Usage of Digital Modulator
A good Digital Moderator should provide a modulation with the low Bit error rate at low SNR, it should perform well in a multipath fading environment, it should occupy minimum Bandwidth and should be cheap and easy. As we cannot get all of these functionalities simultaneously, we use different techniques like a Coherent Digital Modulation Technique or a Non-Coherent Digital Modulation Technique.
In the Coherent technique, the local carrier generated at the receiver is phase locked to the carrier at the transmitter. In the Non-Coherent technique, the detection process does not need a receiver carrier to be phased locked to transmitter carrier which makes this system quite simple.
There are many advantages of using a digital modulation technique like it has greater noise immunity, multiplexing is easier than analog modulation of various types of signals such as voice, video, data etc. Digital information can be saved and retrieved easily and digital modulating techniques can accommodate the digital transmission error, source coding, and encryption.
A Digital RF Modulator converts the video and stereo audio from any A/V component and Video game decks into a coaxial cable output. All you need to do is just connect your A/V component to the Modulators input jack, meaning video input to video in and audio input in audio in or it can also be color coded like yellow for video and red for audio. Then from you modulator find the TV out socket and connect your modulator to your TV via a coaxial cable through that socket and attach it to TV’s input or antenna and select channel 3 or 4 operation and you will be all set to use your RF modulator without any problem.