Wireless Microphones

Wireless Microphones system is designed to replace the cable that usually tethers a wired microphone (or any acoustic transducer) to an amplifier. Wireless Microphones system begins with a typical microphone which responds to sound waves, and delivers essentially equivalent audio frequency electrical waves to an input of a transmitter. The transmitter "sends" a signal to an associated receiver which is connected to the input of the sound reinforcement amplifier, or mixer. The receiver "picks-up" the transmitter signal, and then converts this signal to a usable audio signal which is sent to the sound reinforcement amp or mixer.

Components of Wireless Microphones System:

Microphone or Transducer: Any Wireless Microphones or transducers can be converted to wireless operation with the addition of a transmitter and receiver wireless link. Wireless Microphones as well as piezoelectric pickups commonly used in guitars are the heart of the system long before a transmitter and receiver come into play. It is often said that "garbage in is garbage out," and this phrase couldn't be more true with a wireless system. Any system is only as good as its weakest link, and generally the least expensive way to improve the overall quality of the Wireless Microphones system is to improve the microphone or transducer. Suitable Wireless Microphones should have excellent dynamic range and headroom, and good linearity over the audio range or the end result will be disappointing. When Wireless Microphones system is used, it should include a high quality microphone that is matched to the application.

Transmitters: The transmitter provides the link between the Wireless Microphones and the receiver. The transmitter takes the audio signal from the Wireless Microphones, converts this energy into a frequency modulated carrier (FM) then radiates the modulated RF carrier where it is picked-up by the receiver.

Receivers: The Wireless Microphones receiver reverses the process by receiving the RF signal and converting the carrier signal into a usable audio signal. This is accomplished by a process called heterodyning where the carrier is filtered, then converted to an intermediate frequency (IF) which is a fraction of the original carrier frequency. After filtering in the IF section, the signal is sent to an FM demodulator which separates the superimposed audio signal from the RF carrier, and converts it into a usable microphone signal again. The usable audio signal is then fed to the output which is connected to the amplifier or mixer. The receiver acts like a standard microphone when used in conjunction with a transmitter and Wireless Microphones.

Wireless Microphones can solve many audio problems in production. They are especially useful when talent must be free to roam, such as when doing an ENG report from the lighthouse. At the same time, wireless Microphones can introduce problems. In Wireless Microphones, a dynamic or condenser microphone is connected to a miniature FM (frequency modulated) radio transmitter. Because the Microphones’ audio signal is converted into a radio frequency (wireless) signal and transmitted throughout the production area, these Wireless Microphones are also referred to as RF Microphones.

There are numerous variations of both transmitters and receivers depending on the particular application in Wireless Microphones. There are ways in which we can explore both receivers and transmitters in depth, but we need to begin by examining the different frequency groups applicable to Wireless Microphones first.