Limitations of LC and RC Oscillators
The LC and RC oscillators bandied so far have their own limitations.
The major problem in similar circuits is that their operating frequence doesn’t remain rigorously constant.
There are two top reasons for it viz.
(i) As the circuit operates, it’ll warm up. Accordingly, the values of resistors and inductors, which are the frequence determining factors in these circuits, will change with temperature.
This causes the change in frequence of the oscillator.
(ii) If any element in the feedback network is change, it’ll shift the operating frequence of the oscillator.
Still, in numerous operations, it’s desirable and necessary to maintain the frequence constant with extreme low forbearance.
For illustration, the frequence forbearance for a broadcasting station shouldn’t exceed0.002 i.e. change in frequence due to any reason shouldn’t be further than0.002 of the specified frequence.
The broadcasting stations have frequentness which are relatively close to each other.
In fact, the frequence difference between two broadcasting stations is lower than 1.
It’s apparent that if we employ LC or RC circuits, a change of temperature may beget the frequentness of conterminous broadcasting stations to imbrication.
In order to maintain constant frequence, piezoelectric chargers are use in place of LC or RC circuits.
Oscillators of this type are call clear oscillators.
The frequence of a demitasse oscillator changes by lower than0.1 due to temperature and other changes.
Thus, similar oscillators offer the most satisfactory system of stabilising the frequence and are use in great maturity of electronic operations.
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