Re: 1MHz output impedance query?
Thank you David. I’m absolutely in the “teaching themselves when they find they need it” camp - have been for years.
I’ve had a couple of days off the head-scratching but now I’ve checked that I have around 12V available there will be an LC filter with an emitter follower to provide the 1MHz sine output. Radio1950 provides useful values, but I’m interested to make this a design and learning exercise - it really is time I knew how to calculate filters, and to use the arcane dot commands in LCspice.
Although I know about filters in audio - I've worked with them for many years to roll-off, cut or boost above or below certain frequencies, I don't quite understand what sort of filter I need here. I think it's pass-band but a very narrow one for a single frequency and I get that the action of the filter is to 'round off' the edges of the square wave but that's as far as I've understood. Yes, I know how capacitors work and to a certain extent how inductors work, but the inductors I've used and designed in the past have been for SMPS and working at much lower frequencies. I used some in a 459MHz system I was developing years ago but a pal held my had a lot on that project and did all the tuning circuit calculations.
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Richard
Index:
recursive loop: see recursive loop
Last edited by mole42uk; 26th May 2021 at 6:30 am.
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