Radio Frequency and Intermediate Frequency Amplifiers

Radio Frequency and Intermediate Frequency Amplifiers
RADIO FREQUENCY AMPLIFIERS
INTEMEDIATE FREQUENCY
IF AMPLIFIERS
Audio frequency amplifiers

1. Radio frequency  ( RF ) is any of the electromagnetic wave frequencies that lie in the range extending from around 3 kHz to 300 GHz, which include those frequencies used for communications or radar signals. A   radio frequency power amplifier  is a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of significant power, typically for driving the antenna of a  transmitter. The RF power amplifier circuit uses transistors and integrated circuits to achieve the desired amplification. The basic techniques for RF power amplification can use classes as A, B, C, D, E, and F , for frequencies ranging from VLF (Very Low Frequency) through Microwave Frequencies. RADIO FREQUENCY AMPLIFIERS

2. RF Output Power can range from a few mW to MW, depend by application It is usually optimized to have high efficiency, high output Power  compression, good return loss on the input and output, good gain, and optimum heat dissipation. RF Power Amplifiers are used in a wide variety of applications including Wireless Communication, TV transmissions, Radar, and RF heating RF AMPLIFIERS

3. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called heterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne   radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done . IF amplifiers can change the frequency levels in circuits that are too selective, difficult to tune, and unstable.. It is a fixed frequency amplifier which rejects unwanted signals. INTEMEDIATE FREQUENCY

4. The section of a  superheterodyne  receiver that amplifies signals after they have been converted to the  fixed intermediate-frequency  value by the frequency  converter An amplifying circuit in a radio-frequency (RF) receiver that processes and enhances a  down converted  or  modulated   signal. IF amplifiers can change the frequency levels in circuits that are too selective, difficult to tune, and unstable. It also helps by changing the frequency levels in circuits which improve image display and tuning range. It is a fixed frequency amplifier which rejects unwanted signals. IF AMPLIFIERS

5. Audio frequency amplifiers are used to amplify signals in the range of human hearing, approximately 20Hz to 20kHz,Audio power amplifiers are used to receive the amplified input from a series of voltage amplifiers, and then provide sufficient power to drive loudspeakers. Local oscillator may consist of a variable frequency oscillator that can be tuned by altering the setting on a variable capacitor. Explaining Fig

6. FM RADIO USING RF AND IF

7. Intermediate Frequency amplifiers are tuned amplifiers used in radio, TV and radar. Their purpose is to provide the majority of the voltage amplification of a radio, TV or radar signal, before the audio or video information carried by the signal is separated (demodulated) from the radio signal.. Explaining fig

8. Radio Frequency amplifiers are tuned amplifiers in which the frequency of operation is governed by a tuned circuit. This circuit may or may not, be adjustable depending on the purpose of the amplifier Mixer allows the receiver to be tuned across a wide band of interest, then translates the desired, arbitrary received signal frequency to a known, fixed frequency. This allows the signal of interest to be efficiently processed, filtered, and demodulated Explaining Fig