Author Topic: PLL FM  (Read 1337 times)

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PLL FM
« on: September 21, 2012, 12:02:13 pm »
I discovered how a simple radio can be built with a couple of pll's...

One is used as a transmitter generating the modulated frequency by applying an audio signal to the pin 9... of course the center frequency of the pll must be high as possible...

The other pll will be the receiver will have same capacitor and resistors, however at one of the inputs the antenna will be attached and from pin 10 the demodulated audio will be available.

i think the bigger problem is the antenna design and rf transistors maybe... I'm not familiar with that...

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PLL frequency to voltage
« Reply #1 on: September 21, 2012, 12:09:48 pm »
When you consider the pll as a receiver it can develop many functions that i just discovered...

For example at different frequencies of reception the voltage at pin 10 is different... so many different tasks can be done by pre-seting a function per each voltage level...

pin 10 voltage is = to the pin 9 except its an output of a voltage follower that follows the pin 9 voltage, while the pin 9 is the input of the vco

the filter than can be a band pass selected for the transmitting frequency.. connected to pin 9

There could be a kind of IC that has many outputs each assigned for a voltage level... could be handy... i guess it exists

A remote controller can be constructed employing this technics for example ...