I am constantly on the lookout for effective yet inexpensive means to generate SSB signals. Analog Devices' LTC5598 Direct Quadrature Modulator turns baseband analog I/Q signals into RF from 5MHz to 1.6GHz. Sadly, the performance falls off dramatically for the amateur radio bands below 60 meters.

What would happen, theoretically, if the output of the LTC5598 could be processed through some frequency-dividing means to cover lower frequencies? Would the spectrum of the modulation be preserved, distorted or destroyed?


closed as unclear what you're asking by Kevin Reid AG6YO Mar 10 at 19:29

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    $\begingroup$ It looks like you've substantially changed the question you're asking (from a general technique question to analysis of a very specific case). It's not good to change a question such that it invalidates existing answers — please consider asking a new question instead. $\endgroup$ – Kevin Reid AG6YO Mar 10 at 16:12
  • $\begingroup$ @KevinReidAG6YO I edited my question when it became clear that my original question was not understood. Sadly, I was unable to delete my original question, but I didn't want to introduce confusion with two identical questions. If you have the power to delete my original question, I will be happy to post a new question. $\endgroup$ – Brian K1LI Mar 10 at 17:41
  • $\begingroup$ Yes, questions can't be deleted when they have answers (exact rules). That and the above are to ensure that answers people have worked on remain both accessible and in context of the question. Please post a new question and return this question to its original, more broad form (or I can do that for you, but you have to post the new question). $\endgroup$ – Kevin Reid AG6YO Mar 10 at 17:57
  • $\begingroup$ (If it helps, we can close this question too — that preserves the answers but indicates that the question is unclear/deprecated and new answers aren't wanted.) $\endgroup$ – Kevin Reid AG6YO Mar 10 at 18:02
  • $\begingroup$ Sure, please close the question. $\endgroup$ – Brian K1LI Mar 10 at 18:25

The spectrum of the modulation would also be reduced. Imagine a 1MHz suppressed-carrier upper-sideband signal (so that we can talk about the carrier, as well) that has a single audio tone of 1kHz as its modulation. The result is two frequencies: The carrier (1MHz), and the carrier plus the tone (1.001MHz). Now divide that by two and you get 500.5kHz. If we demodulate that, we get a 500Hz tone. (Also note that a true analog frequency divider is more complicated than a digital divider.)


You could use a device known as a downconverter (or "transverter"), like this (but there may be others that are cheaper and/or easier to setup and use). It can take a high-frequency signal and downconvert it ("shift" it down). In theory, the spectrum shape is not modified at all; it is just shifted from a larger to a smaller frequency.


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