What is an Intermediate Frequency Amplifier?

Intermediate Frequency Amplifier
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What is an Intermediate Frequency Amplifier?

What is an Intermediate Frequency Amplifier?

Intermediate frequency amplifiers, also known as IF amplifiers. These are stages of amplifiers that are used to boost signals in TV and radio receivers. These amplifiers operate at frequencies that are intermediate to those of the high radio-frequency signal coming from the antenna and the low frequency of the video or audio signal that the receiver is getting. They do so at a range of frequencies known as intermediate frequencies.

How does an Intermediate Frequency Amplifier work?

In the heterodyne receiver, the IF amplifiers typically come after one stage of the RF amplifiers. They add leverage in a frequency region between the radio frequency that is input and the video frequency or audio bandwidth that is output. This makes it possible to get the majority of the leverage fixed from an amplifier with a fixed frequency, making tuning much easier. Compared to the predecessor, a tuned radio frequency receiver, this one is far more advanced. To provide the necessary frequency response, intermediate-frequency (IF) amplifiers may make use of amplifiers with double-tuning or asymmetrical tuning. Some employ the utilization of several IF frequencies.

Amplifier VS. Intermediate Frequency Amplifier  

Audio frequency amplifiers increase frequencies between 20 Hz and 20 kHz. Some Hi-Fi amplifiers increase this range to 100 kHz, while others limit it to 15 kHz or less. Audio voltage amplifiers boost low-level signals from microphones, disk pickups, etc. Amplifiers’ auxiliary circuitry does tone correction, signal level equalization, and input mixing. Amplifiers have high voltage gain and high output resistance. Audio power amplifiers accept boosted input from voltage amplifiers and drive loudspeakers.

On the other hand, intermediate-frequency amplifiers are for radio, TV, and radar. The main aim is to amplify TV or radar signals before separating or demodulating the audio or visual information. Amplifiers operate at a lower frequency than received radio waves but higher than audio or visual transmissions. IF’s frequency. The amplifier’s bandwidth depends on the equipment utilized. AM radio receivers and I.F amplifiers operate at 470 kHz, and their bandwidth is 10 kHz, 465 kHz to 475 kHz. Home TV utilizes 6 MHz bandwidth for the I.F signal at 30 to 40 MHz, and radar may use 10 MHz.

Intermediate Frequency Amplifier for High Frequency 

An IF-based receiver layout reduces the number of components that must function at the signal’s high frequency. As frequencies grow into the gigahertz region, everything gets more difficult. Semiconductors have less power, passive components differ from low-frequency versions, and transmitting effects become more noticeable.

Intermediate Frequency Amplifier for Tunable Receivable 

Many of the high-frequency components and circuits of a tunable receiver must be consistent with the complete range of conceivable carrier frequencies. It is undesirable because it’s easier to build RF components and circuits tuned for a narrow range of signal frequencies. As a result, tuning would necessitate the usage of many knobs, as different subcircuits would need adjustment based on the specified frequency of the device. An intermediate frequency band is selected by a heterodyne receiver, which then optimizes its remaining circuitry for this frequency range after reducing the received spectrum.


Intermediate frequency amplifiers simplify receiver design and lessen the number of high-frequency components.  The design simplifies bandpass filter design because of the lower Q-factor.  IF-based systems implement quadrature demodulation more robustly.

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