RF Generators
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What would it take to build an RF generator operating at cellphone frequencies? Just curious..
you can possibly do well with an audio amplifier circuit.
For example the LM386 chip probably can amplify 100 khz to
around 100 milliwatts. Maybe 5 watts out of an LM383.
Which reminds me, I saw a circuit for transmitting 1000 khz
made out of an LM317 voltage regulator about a month ago...
That's a 1-amp chip! Oh, Here it is!
Voltage regulator used as transmitter
You can power it with from 5 to 15 volts; its output swings almost down to ground and almost up to the power supply voltage and can supply up to 200 mA. By choosing the two resistors and the 1 capacitor sizes, you can vary its period of oscillation from hours to microseconds (yes, it can oscillate at 1 MHz). The LM555 costs $1.49 at Radio Shack; the resistors and capacitor $1.00 each (being overpriced). For what it does, it's a sweet chip. Great for toys, from timing applications to a metronome to an electronic organ; from a car burglar alarm to a touch switch to pulse width modulation applications.
Another way is to buy a clock oscillator, a little 14 pin metal package; you purchase it for the frequency you want. Again, the output is a square wave. They are mostly crystal controlled, and run from 1 MHz to 20 MHz; you could divide the output down by half (multiple times) with another IC such as the CD4017 to get to the frequency you want.
If the purity of your sine waveform is important, then a tank circuit based oscillator would be best.
If I'm unable to get one, I'll just make a variable tank circuit, though it won't be as good as a professionally made one :P
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