Many electronic devices commonly used in most households emit pulses of energy which travel through an area of space and are manipulated to decode information into the receiving device. For radio frequencies (RF), this process is known as modulation. The frequency range upon which a device is transmitting energy determines the necessary strength of manipulation. An ultra high frequency (UHF) modulator, for example, would be used to emit energy to be received by a device such as a television satellite dish. UHF modulators also can be used with other devices that use electromagnetic waves at a frequency of 300-3,000 megaHertz, such as digital video disc (DVD) players, citizen's band (CB) radios and devices with WiFi capabilities.
The electromagnetic (EM) spectrum consists of a multitude of energy waves existing together. Each wave contains variables of length, intensity, frequency and amplitude that determine its position on the EM spectrum. On the highest end of the EM spectrum are gamma rays, which are highly intense. Radio waves exist on the lower end of the spectrum. The length of a wave decreases as its frequency increases.
With consideration to wave frequency, UHF waves would be higher on the radio frequency side of the EM spectrum. Simpler RF modulators would be unable to decode these higher frequency waves, so in order to obtain the information being carried by UHF waves, UHF modulators would be required. Considering two commonly known types of modulators against one another makes the comparison of RF to UHF modulation easier to understand. These modulators are known as frequency modulation (FM) to amplitude modulation (AM).
UHF modulators can be commonly found for sale at many retail locations. One might purchase UHF modulators to transmit satellite signals. The signal is ultimately received through a series of antennas and wires until it reaches a box in which the signal is modulated, also as UHF, and then transmitted to the purchased UHF modulator connected to a television in another room of the house, which would then be able to receive the same information.
In this case, that information would be sound and video from a satellite feed. The process of UHF modulation begins when a information is coded into a device, which occurs through a series of electronic pulses. This electricity then travels through a series of wires, creating an electromagnetic field.
When an electromagnetic field is created, outward waves follow the naturally occurring EM spectrum traveling through the atmosphere. When these waves are collected by an antenna, the antenna moves pulses of energy down into the electronic device. If the receiving device has its own modulator built in, then it can also send out its own signal.