I have tried looking a couple different places but cannot find a concise explanation on the difference between a frequency synthesizer and a frequency mixer. My goal is to take a signal at 915 MHz and upconvert it to a 2.4 GHz signal. I am not trying to amplify so that I can stay down on noise. Would somebody be so kind as to help me out?

Thanks in advance.


1 Answer 1


A frequency synthesizer does exactly what its name implies. I synthesizes a frequency. Often these are adjustable so that they can generate a range of frequencies.

A mixer, on the other hand takes two signals and produces an output which amounts to the sum of the two and the difference of the two.

So this would be useful for your upconverter. If you take your 915 MHz signal and mix it with 1.485 GHz you will get two outputs, one at 2.4 GHz and another at 570 MHz. If you then high-pass filter the output you will be left with the 2.4 GHz signal.

  • \$\begingroup\$ This may be me just not understanding, but if I wanted to mix in both directions with one radio so that I could both transmit and receive data successfully, would I be able to accomplish this with a bidirectional mixer? \$\endgroup\$ Feb 19, 2021 at 17:15
  • \$\begingroup\$ Typically the receiver and the transmitter are separate sections and use their own mixers. In most cases the requirements for a receiver mixer and a transmitter mixer (often called an upconverter) are different enough that there is no point in trying to make one mixer, which is a simple enough circuit, share both duties. \$\endgroup\$
    – jwh20
    Feb 19, 2021 at 17:22

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