Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
That circuit is not an oscillator. You could use a balanced mixer with 15 HZ mod frequency, will give Fc + 15HZ and Fc -15HZ on the same wire. It might be hard to filter off each component. The next step would be a phasing method of generating just one side band. The second side band could be generated using some of the common components (Fc+- 90 degrees, Fm +- 90 degrees).
Frank
Hi,
I have no good experience with two oscillators next to each other.
They usually influence each other resulting in clock jitter.
Many years ago i had two oscillators in one 74HC device, one was about 11MHz, the other 14MHz .. they always output the same frequency. Probably influenced by a not good pcb layout.
Klaus
I think the answer to the original question is "no", because the (necessary) nonlinearity of the oscillator doesn't allow independent oscillation modes to be build up. Particularly not with this low frequency difference which will most likely result in a single output frequency. In case of higher frequency difference you possibly get unstable behavior but unlikely two separate signals.
The diplexer method will work neither. Crystal Q isn't high enough to separate both frequencies (presumed they would be generated).
Obvious question, why not using two oscillator transistors? You still need to separate both oscillators thoroughly to avoid one signal "pulled" to the other frequency.
Hi,
what about using a (two) PLL to generate the two frequencies?
Klaus
If they are two close, they usually lock to each other. They need good buffering to avoid this and maybe something like this output network
(http : // www . ab4oj . com/test/imdtest/images/fig9.gif )
The reason I want to use a single oscilator with two resonators, is to eliminate different drifts, since any drift in the oscillator, will affect both output frequencies at a quite equal amount (asumming the crystals have relatively matched characteristics).
This is the solution.That circuit is not an oscillator. You could use a balanced mixer with 15 HZ mod frequency, will give Fc + 15HZ and Fc -15HZ on the same wire. It might be hard to filter off each component. The next step would be a phasing method of generating just one side band. The second side band could be generated using some of the common components (Fc+- 90 degrees, Fm +- 90 degrees).
Frank