Part of the Wireless technologies glossary:

Superheterodyne refers to a method of designing and building wireless communications or broadcast equipment, particularly radio receivers. Sometimes a receiver employing this technology is called a "superheterodyne" or"superhet."

In many wireless applications, the equipment must function over a range,or band, of frequencies.  But it is easier to process a modulated signal at a single frequency than over a band, especially if the highest frequency in the band is much different than the lowest frequency. Toovercome this inherent difficulty when engineering variable-frequency wireless equipment,the desired data-carrying signal can be combined with the output of an unmodulated,variable-frequency oscillator (VFO) in a circuit called a mixer. When this is done,output is produced at a fixed frequency representing the difference between the input frequencies.

When the correct range of frequencies is chosen for the VFO, a receiver can be designed that will intercept incoming signals over a specific band. For example, if the desired input frequency range is 20 MHz to 25 MHz, a VFO can be built that generates an unmodulated carrier at 29 to 34 MHz.  When the incoming signal is mixed with the VFO output, the resultant has a constant frequency of 9 MHz, representing the difference between the frequencies of the inputs. The 9-MHz output retains the modulation characteristics of the incoming signal. In this case, the receiver is said to have an intermediate frequency (IF) of 9 MHz. This IF signal can be amplified and filtered more easily than signals having frequencies that vary from 20 to 25MHz.

The theory and design of superheterodyne equipment is a rather sophisticated business. Numerous books are devoted to this topic; some engineers make their entire living designing oscillators, mixers, and amplifiers that use this technology. For more information about superheterodyne engineering practice, a professional-level textbook or a formal course is recommended.

This was last updated in June 2010
Posted by: Margaret Rouse

Related Terms

Definitions

  • mPOS (mobile point of sale)

    - An mPOS ( mobile point of sale) is a smartphone, tablet or dedicated wireless device that performs the functions of a cash register or electronic point of sale terminal (POS terminal). (SearchCIO.com)

  • Wi-Fi Alliance

    - The Wi-Fi Alliance is a wireless industry organization that exists to promote wireless technologies and interoperability. The Alliance also certifies products that comply with their standards for W... (WhatIs.com)

  • Wi-Fi

    - Wi-Fi is the popular term for a high-frequency wireless local area network (WLAN) technology and standard that has gained acceptance in many companies as an alternative to a wired LAN...(continued) (SearchMobileComputing.com)

Glossaries

  • Wireless technologies

    - Terms related to wireless technologies, including definitions about wireless devices and words and phrases about radio, microwave and infrared communication.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question About superheterodynePowered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.