What is Frequency Translation (Frequency Mixing or Heterodyning)

In this post we will discuss, what is Frequency Translation. This is also known by other names like- Frequency Mixing, Frequency Conversion or Heterodyning.

What is Frequency Mixing (Frequency Conversion/ Heterodyning/Frequency Translation)

It is generally required to translate or shift the modulated signal to a new band of frequency in the processing of signals in the communication systems.
Because the received signal translated to a fixed intermediate frequency (IF), can easily be Amplified, Filtered and Demodulated (Detected).

For example- in most commercial AM radio receivers, the received radio frequency (RF) signal is 560- 1640 kHz. But this is shifted to an Intermediate Frequency (IF) which is 455 kHz band, for the purpose of processing.
This is done because the received signal, that has been translated to a fixed intermediate frequency, easily be Amplified, Filtered and Demodulated.

The device which is used to perform this operation of frequency translation of the modulated wave is known as the "Frequency Mixer" and this process is also called as frequency conversion, frequency mixing or heterodyning.

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Need and benefits of modulation
Amplitude modulation (time domain equations and waveforms)
Frequency spectrum of amplitude modulation (waveforms and equations derivation)
Amplitude modulation vs frequency modulation (advantages and disadvantages)
Conventional AM vs DSB-SC vs SSB-SC vs VSB (comparison of AM systems)
Low level and high level modulation block diagram (AM transmitter block diagram)
Frequency translation / frequency mixing / frequency conversion / heterodyning (basic concepts and need)