We have different types of radio transmitters and they can be classified according to the type of modulation used, according to the service involved.
According to the type of modulation used radio transmitters can be further classified into three types namely Amplitude modulation, Frequency modulation and Pulse modulation techniques. In Amplitude modulation transmitters the modulating signals modulates the carrier. Such transmitters are used for the radio broadcast on long, medium and short waves, radio telephony on short waves, television picture broadcast on very short waves or ultra short waves. In a frequency modulation transmitter the signal voltage frequency modulates the carrier. Such transmitters are used for radio broadcast in the very high frequency and ultra high frequency range, television sound broadcast and radio communication. In a pulse modulation transmitter the signal voltage alters some characteristic of the pulses. These characteristics of the pulses altered on modulation may be pulse width, pulse position, pulse amplitude, pulse frequency or the pulse code.
According to the type of service involved the radio transmitters can be classified differently like Radio broadcast transmitters. These transmitters are designed for transmitting speeches, talks, music, dramas, commentaries and news etc. for the information and recreation of people. The electromagnetic energy is so radiated from the transmitting antenna that the largest number of people may be able to receive the broadcast with the help their of radio receiver. These broadcast transmitters may be either amplitude modulated or frequency modulated. The amplitude modulated transmitters may be either amplitude modulated or frequency modulated. The amplitude modulated transmitters operate on long waves, medium waves and short waves and radiate carrier power as low as about one kilo watt and as high as one hundred kilo watt or more. The frequency modulated broadcast transmitters operate on very short waves or on ultra short waves and radiate carrier power of the order of one hundred kilo watts or so.
The radio telephone transmitters are designed for transmitting telephone signals over long distance by radio means. A radio telephone transmitter uses certain special devices as volume compressors, privacy devices, peak limiters etc. The transmitting antenna is designed for beaming the electromagnetic energy into a narrow beam directed toward the distant receiving antenna. Smaller amount of power is thus required.
A radio telegraph transmitter transmits telegraph signals from one radio station to another radio station. It may use either amplitude modulation or frequency modulation. When point to point radio communication is involved, the transmitting antennas are highly directive so that the electromagnetic energy is beamed into a narrow beam directed towards the receiving antenna at the receiving radio station. The television broadcast requires two transmitters one for transmission of picture and other for transmission of sound.
About the Author:
Tymon Hytem has worked in the electronics feild for the past 15 years. He enjoys helping people decide on electronic gadgets from finding the right phone for your business and can help you choose the perfect Background Music for your business needs.
