2-60 MHz VCO?
2-60 MHz VCO?
(OP)
Anyone have an idea of how to design a 2-60 MHz VCO with low power consumption? A DDS approach would draw around 3X too much power. I was thinking about some sort of switched reactances resonating with a varactor....
RE: 2-60 MHz VCO?
2MHz-60MHz is too much range for a basic VCO.
RE: 2-60 MHz VCO?
I have been hearing about tunable thin film ferrites, etc. Was wondering if anyone had any wild ideas.
RE: 2-60 MHz VCO?
Thinking again about your first post, it seems as though you are able to use a VCO which is discontinuous in its tuning capability, having to switch between ranges. This obviously allows more flexibility.
I am not sure why direct digital synthesis must necessarily consume 3x too much power. What power consumption are you hoping for and for what signal level?
So we could make the fundamental as an on-off square-wave switched power rail. Now we have odd harmonics to infinity. That means we need 61dB attenuation at the third harmonic to meet your requirements. Any sort of tuneable filter is bound to create its own distortion problems so switching in fixed filters is more likely to succeed. If we went in octave fundamental tuning bands we would have:
2-4MHz
4-8 MHz
8-16MHz
16-32MHz
32-64MHz
In other words 5 switched harmonic filters, which is not too bad. The trouble is they now require 61dB attenuation from double the fundamental to three times the fundamental, quite a steep filter characteristic.
How about also creating the third harmonic as a switched square wave, then summing with the fundamental to remove the third harmonic. This simplifies the filter characteristics and should be workable.
RE: 2-60 MHz VCO?
I have maybe 35 mA at 3 V to work with.
RE: 2-60 MHz VCO?
The power available is one piece of data, but the signal level required is also important!
RE: 2-60 MHz VCO?