Browse Definitions :
Definition

superheterodyne

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
SearchCompliance
  • OPSEC (operations security)

    OPSEC (operations security) is a security and risk management process and strategy that classifies information, then determines ...

  • smart contract

    A smart contract is a decentralized application that executes business logic in response to events.

  • compliance risk

    Compliance risk is an organization's potential exposure to legal penalties, financial forfeiture and material loss, resulting ...

SearchSecurity
  • buffer overflow

    A buffer overflow occurs when a program or process attempts to write more data to a fixed-length block of memory, or buffer, than...

  • biometric verification

    Biometric verification is any means by which a person can be uniquely identified by evaluating one or more distinguishing ...

  • password

    A password is a string of characters used to verify the identity of a user during the authentication process.

SearchHealthIT
SearchDisasterRecovery
  • What is risk mitigation?

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a business.

  • change control

    Change control is a systematic approach to managing all changes made to a product or system.

  • disaster recovery (DR)

    Disaster recovery (DR) is an organization's ability to respond to and recover from an event that affects business operations.

SearchStorage
  • What is RAID 6?

    RAID 6, also known as double-parity RAID, uses two parity stripes on each disk. It allows for two disk failures within the RAID ...

  • PCIe SSD (PCIe solid-state drive)

    A PCIe SSD (PCIe solid-state drive) is a high-speed expansion card that attaches a computer to its peripherals.

  • VRAM (video RAM)

    VRAM (video RAM) refers to any type of random access memory (RAM) specifically used to store image data for a computer display.

Close