Hi, guys!
I have a question about sub-harmonics.
when I calibrated signal generators, I had to calibrated sub-harmoics. But I cant understand about it what it is.
There are some kinds of definition about it like 1/n frequency of fundermental.
And some people says it is harmonics's harmonics.
what is real one?
Some generators use multipliers to generate the higher output frequencies.
For example a generator with an internal oscillator range of 500 to 1000 MHz (call this Band 1) can be extended to 2000 MHz by having a 2X multiplier. When this generator is set to 2000 MHz (band 2) it should only output the 2000 MHz signal but it may have a sub-harmonic of 1000 MHz, the sub-harmonic 1/n, in this case would be 1/2. This 1000 MHz sub-harmonic is actually the original Band 1 frequency that has not been filtered out after the 2X multiplier.
If this generator also has a 3X multiplier then at 3000 MHz (Band 3) you would look for sub-harmonics at 1/3 and 2/3 which would be 1000 and 2000 MHz. You might also see a sub-harmonic at 4000 MHz 4/3.
It is useful to know what band (multiplier) you are in when looking for the sub-harmonics but normally they will be exact sub-multiples like 1/2, 3/2, 1/3, 1/4, 2/3, 3/4.
Hope this helps a little.