[SOLVED] sine wave generation through analogue circuit

[fareen]

hi
im tring to produce sine wave using a LC oscillator
but im getting output as shown in figure
can sumone give a hint how to improve the output??

 

[LvW]

I think your oscillator works well - as far as the simulation is concerned.
However, the graph does not look as desired because of timesteps that are to large.
Repeat the simulation with smaller timesteps - and you will be satisfied (I hope).

 

[fareen]

thanks lvw
but can you suggest the setting required for the simultion

 

[LvW]

thanks lvw
but can you suggest the setting required for the simultion

As your oscillation period is approx. 100ns I would use 100ps as the max. time step.

 

[fareen]

thanks lvw
but if i want to simulate thhe same circuit in lt spice then what value of capacitances and inductances should i place in the model

 

[Syncopator]

The diagram is of a crystal oscillator, not an LC one.

 

[fareen]

The diagram is of a crystal oscillator, not an LC one.

so what u suggest i use???
i have another question how can we adjust the output gain wiith the help of capacitors??
is this circuit capable to give 3v peak amplitude??
i m having problem implementing the circuit
im getting ditorted output wave form with .5v peak??
can u suggest some improvemnet

 

[LvW]

Simple answer:
I suppose you have designed the circuit - and parts values are calculated according to the desired oscillation frequency.
Why not use these values for simulation?
(Do you expect that we select values without knowing the frequency?)

 

[Syncopator]

so what u suggest i use???

A Colpitts or a Hartley circuit, neither of which have crystals.

 

[fareen]

you are right syncopator but i have use crystal to ensure good quality of oscillation and to get the require frequency.
im having problem in adjusting the gain ???

 

[Syncopator]

i have use crystal to ensure good quality of oscillation and to get the require frequency.

That's ok. But you can also get a good clean sine wave from LC oscillators.

It's been a long ... long time since I constructed any of them. I would suggest looking for published circuits of all three types of oscillator, crystal, Colpitts and Hartley, and copy one which was designed to work at or near your frequency of operation. It should then be a simply matter to change the frequency to the one desired.

 

[LvW]

you are right syncopator but i have use crystal to ensure good quality of oscillation and to get the require frequency.
im having problem in adjusting the gain ???

fareen, what really is the problem?
In your first posting you have presented a circuit and a simulation result, which has confirmed the oscillation capability of the circuit.
For my opinion, only the time resolution was not OK. So - what is the problem now?

 

[Syncopator]

The inductor in the emiter shouldn't be necessary. Try removing it. Also try changing the value of the 300pF capacitor to 100pF.

 

[fareen]

in simulation its working fine but in actual implementation with discerete components im not getting the required result
the amplitude is too loo