LT6236CS6IC OPAMP GP 215MHZ RRO TSOT23-6It regulates by going into saturation which reduces the gain to zero. 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. The Cap can be tied to 5V or 10V. This was designed for 5V R-R output. Bipolar positive peak.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. Pulse generator, Wavetek Model 142 HF VCG generator.
Cheap and Dirty Compute R values from Sine in Excel.Reverse engineer the FM sine gen, in a old Wavetek , HP or sim. any VCO into a counter with R,2R,4R,8R DAC or use 1 or 2 Johnson Counters with sine function weighted resistors. 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. 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.
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