Dear All!
Can some body help me in learning the basics of Oscillators, VCO and Phase detectors.
Thanks

 

That's too complex to sit here and spend hours writing about.

See top of page, note links in light blue:

Vol. I - DC
Vol. II - AC
Vol. III - Semiconductors
Vol. IV - Digital
Vol. V - Reference
Vol. VI - Experiments
Worksheets
Videos

Of course theres always this link: http://tinyurl.com/23uo7gs

 

Hello,

Your question is quite broad.
Can you be more specific?
I can only give some linkpages on the subjects:
http://www.educypedia.be/electronics/analogoscil.htm
http://www.educypedia.be/electronics/vco.htm
http://www.educypedia.be/electronics/pll.htm

Bertus

 

The basics?

Oscillators are circuits that create an AC signal. They ussually do this by inverting and delayed feedback - which is feeding the circuit its own output as an input.

A Voltage controlled Oscillator will have elements Like a reverse bias high capacitance diode or varactor that are changed by application of a control voltage. These changes will cause a shift in the oscillators frequency tuning.

 

A phase detector looks at two signals (one of them its own VCO for a PLL) and outputs the difference frequency. A phase locked loop or PLL is the normal method of doing this. It is a VCO that feeds back the phase difference as its control voltage. This allows it to demodulate FM radio signals.

Another use is clock syncing. If the clock drifts it creates a phase difference that controls the VCO back towards sync. The synced clocks willl have a flat 0 volt signal for the phase detected.