If xr2206 is used to generate a sine wave does it have dc component? Based on my analysis it does not have.
Risetime and slope are two different things. A sinewave of higher amplitude will have a steeper slope, but the rise time will be the same as it takes the same amount of time to get from the lowest point to the highest point. Also, a sinewave by definition has only one frequency component, regardless of its amplitude. A sinewave is fully defined by a frequency, amplitude, and phase offset.
Waves which are not sinewaves can be thought of as a summation of a bunch of sinewaves. For instance, a square wave contains all of the odd harmonics - 3, 5, 7, 9, etc. times the fundamental frequency. The more of these harmonics are present, the flatter the tops and bottoms of the wave become, and the steeper the transitions become. With a square wave, the sharper the edge, the more harmonics are required to represent it. However, this has nothing to do with the amplitude - if you double the amplitude, you don't double the number of frequencies required, you just double the amplitude of all of the harmonics.
However: The slope of a sinewave does change as you increase the amplitude, and slope can sometimes be an issue! Op amps generally have a specified output slew rate that limits the slope of the signal that it can reproduce. It turns out that if you build an op amp circuit that has enough gain, you can run into the slew rate limit before the 3 dB bandwidth limit with a large enough signal. When this happens, your nice sinewave will become a triangle wave at the output. Naturally, this distortion will create more frequency components than the original signal.
@rocketracket The frequency will change either by shunt attenuating or Series R. both resulting in attenuation and frequency shift. But the FET AC drop distorts low freq. sine. while the Pot does not.
I still don't know what this is for and it is better with a PLL. If you value your time. Contact me.
For 1~200MHz, custom video design with current control is needed.
The 199 vs 200 difference inversely controls the Q and so 198 is faster but starts to clip. This was designed for 5V R-R output. The Cap can be tied to 5V or 10V. This gives a step pulse to one CAP to kick start Oscillator otherwise it takes a long time to grow to full swing.
This is not a custom design service site, but this design is custom from me.
Obvious choices are Op Amp or video amp with BW > 30MHz. e.g. LT6236CS6IC OPAMP GP 215MHZ RRO TSOT23-6
It regulates by going into saturation which reduces the gain to zero. Since gain or Pot R controls frequency, and amplitude of the integrator, the output adjusts to peak to peak swing. Naturally, a quick change in R changes gain momentarily over a 4:1 range, but the sine Vpp regulates according to matched feedback with <1% R mismatch gain for loop bandwidth or Q or clipping tradeoffs.
It is not intended for rapid FM but for pure sine as the Q is quite high for pure sine.
The other approaches
- Take any simple Relaxation triangle VCO and convert to sine , with bipolar triangle, using back-back LED or Zeners and R to regulate smooth linear to sine gain reduction curve after 2/3Vpp.
- any VCO into a counter with R,2R,4R,8R DAC or use 1 or 2 Johnson Counters with sine function weighted resistors. Cheap and Dirty Compute R values from Sine in Excel.
reverse engineer the FM sine gen, in a old Wavetek , HP or sim. Sig Gen,
Use 400MHz VCO and down convert