- #1
mearvk
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So couple questions.
My assumption is that a radio antenna gets bombarded with all frequencies at the same time. So there has to be a discriminating circuit with a radio to act as a frequency filter.
Well could I do this naively with a low pass filter and a high pass filter together? In other words, if I made a tuned, static (no ability to change it) band-pass filter (say at 100MHz +/- 20Khz) and added another low pass filter at 20 kHz and then hooked that into an amplifier of some sort would I be able to listen to a radio station of my choosing? Adding variable resistors would allow me to tune it I guess. I guess the demodulation might be more complicated than that.
In the age of ICs how is the frequency generation for FM band transmission typically accomplished? There are frequency crystals which have some minor ability to vary, there are MCUs which can use PLLs but it isn't clear that a MCU w/ PLL @ 96 MHz can vary enough to really handle the FM spectrum. I'm really unclear on that. I don't want to mess with tank circuits since they sort of beg the question and can be unstable. So what does that leave?
Edit: Basic, basic question. How does one wire an antenna into one's circuit?
Thanks.
My assumption is that a radio antenna gets bombarded with all frequencies at the same time. So there has to be a discriminating circuit with a radio to act as a frequency filter.
Well could I do this naively with a low pass filter and a high pass filter together? In other words, if I made a tuned, static (no ability to change it) band-pass filter (say at 100MHz +/- 20Khz) and added another low pass filter at 20 kHz and then hooked that into an amplifier of some sort would I be able to listen to a radio station of my choosing? Adding variable resistors would allow me to tune it I guess. I guess the demodulation might be more complicated than that.
In the age of ICs how is the frequency generation for FM band transmission typically accomplished? There are frequency crystals which have some minor ability to vary, there are MCUs which can use PLLs but it isn't clear that a MCU w/ PLL @ 96 MHz can vary enough to really handle the FM spectrum. I'm really unclear on that. I don't want to mess with tank circuits since they sort of beg the question and can be unstable. So what does that leave?
Edit: Basic, basic question. How does one wire an antenna into one's circuit?
Thanks.
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