We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is Intermediate Frequency?

By Geisha A. Legazpi
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Intermediate frequency (IF) is a replica of a received signal but with frequency that is shifted usually below radio receiver frequency. The use of intermediate frequency is a result of the efforts to build a receiver capable of a wide range of receiver frequencies. IF is often used to increase signal processing or convert frequencies to a common one for processing.

Radio receivers are a series of progressive signal amplification by a set of cascaded radio frequency (RF) amplifiers. Amplifiers increase the signal level, which means the antenna signal has to be fed to a very sensitive first stage, amplified, and sent to the second stage and so on for further amplification. The first radio receivers built were tuned radio frequency (TRF) receivers, which had RF stages that were all tuned to the receiver frequency. TRF receivers are best suited for receiving only one frequency. For tuning to a wide range of frequencies, TRF receivers may not be practical except in special applications.

A common broadcast amplitude modulation (AM) radio is capable of receiving about 580 to 1,600 kiloherz (kHz). In tuning, a resonant circuit, usually a tuned frequency transformer’s shunt capacitance, is decreased to tune to higher frequencies. At some point, the circuit ends up with a complicated ganged-tunable multi-capacitor with four separate capacitors. The next concern is undesired coupling of the signal on the fourth stage output, finding its way into the input of the first stage. All these result in noisy speaker output.

Other limitations of TRF receivers include complicated design of the inductance and capacitances needed in the tuned circuits. The solution is to replace most of the RF stages with IF amplifiers with fixed frequency tuned transformers. These intermediate frequency transformers have a primary winding and a secondary winding wound on an adjustable core.

The IF strategy is to shift the frequency of the received RF so that it is fixed at the IF value. For reception of 580 kHz, for example, the receiver generates a local frequency of 1,035 kHz. The difference of the local frequency and receiver frequency is 455 kHz, which is the intermediate frequency. This same process is duplicated at various local frequencies, which means tuning to a wide range of receive frequencies is simplified when using IF.

An intermediate frequency amplifier is tuned only once in the factory. A device that is already tuned to the specific IF is called an intermediate frequency filter. Most of these filters are quartz-controlled or pre-cut crystals tuned to the IF. The intermediate frequency is used in almost all radio receivers categorized as heterodyne or super-heterodyne receivers.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Link to Sources

Related Articles

Discussion Comments
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.