March 29, 2017 04:58PM
It seems most frequency control systems have gone over to synthesis, where a single common and cheap (I mean pennies) oscillating crystal is the reference for every frequency needed in a radio. It could be 10 mhz., and I've seen a single 32.768 crystal used as a reference in a tiny mp3 FM transmitter, creating the carrier and all other frequencies needed for an FM stereo signal digitally.

I'm excited about the possibilities, though it is sad when simple and direct circuits aren't as easy to make. A nice crystal oscillator with clean, stable output can be made from 5 parts, versus 25 parts for a phase locked (PLL) synthesizer. The PLL can tune a wide frequency range in steps, though the signal is not as pure. It's still cheaper for the parts for whole PLL than getting one custom crystal made.

I'd like to see VFO oscillators come back.. :) Those were used in the early days of radio, just an inductor-capacitor tuned circuit, with wire wound on an oatmeal box in those times. Simple circuits with discrete components are the best for a beginner learning electronics I think, the way to visualize what the circuit is actually doing.

Subject Author Views Posted

International Crystal Manufacturing Closing Shop!

ThaDood 503 March 23, 2017 07:23AM

Re: International Crystal Manufacturing Closing Shop!

Radio Animal 323 March 29, 2017 04:58PM

Re: International Crystal Manufacturing Closing Shop! Jan Crystals info.

ThaDood 354 May 21, 2017 09:40AM

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