Hi,
I appreciate the input. The frequency isn't close to 70kHz as my target frequency is 40kHz. It works okay with the inductor-capacitor frequency wise, the inductor capacitor series "rounds" up the edges of the sawtooth wave so after the filter it looks almost sinusoidal. To be honest, I don't think it matters that much if I'm transmitting a triangle or a sinusoid. Vpp of the output should be as high as possible and in sinusoid waveform (ideally). The wave itself goes to the transmitter afterward, and I thought that sinusoidal wave absorbs less noise (the wave is w/o harmonics) so it'll be easier to detect in the receiving end.
I'm trying to design the filter a very narrow bandpass filter for this, without much success so far. Another problem is that I don't know where I can find the TL071 in such a short notice, I'm not sure the stock room in my school carries it.