Re: oscillaror simulation with ADS

Please ask your Professor what will limit the base current of VT2. As drawn the transistor will fail because of a very high base current that will blow the b-e junction of VT2. The b-e junction is connected virtually direct over the 5V supply with only the inductor resistance of the 18uH and 10nH coils in series. It should be obvious that a lot of base current will flow.

The transistors used in the ADS simulation was according to the original circuit. (BC848 and BFR93A)
The BC848 can be replaced by any general-purpose NPN like, 2N2222, 2N3409, 2N4401 etc. It won't make any noticeable difference in the results.

i have a question.in transient simulation in ads,output signal must be a pure sinusoidal signal or not?in harmonic balance simulation i achieve to diagram of harmonics,as your attachment.but output waveform is npt sinusoidal.why?

because there are a lot of harmonics, you need filter the base of your waveform.

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because there are a lot of harmonics, you need filter the base of your waveform.

Yes, sampling on the collector will be rich in harmonics. Try sampling on the emitter and you should get a much cleaner waveform. The best will be to sample from the tank circuit with a high impedance buffer.

thanks for your attention.this is true.because alot of harmonic exist,then waveform is not pure sinusoidal.
how i can sample in emiiter? namely i named emitter leg with Vout and see it?
another question:in a good design of oscillator,output waveform must be pure sinusoidal?namely other harmonics are weak rather than fundamental frequency?

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E-design...about second circuit,where VT2 transistor is really negative resistance,because of high collector current from DC analysis (Ic=51 mA),we must use from a transistor with Ic,max>51 mA.i will simulate this circuit with such transistor and attach my result.

can anyone give me NEC_2sc3358 BJT transistor nonlinear model?
thanks...

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namely internal inductances and capacitances of transistor and noise model of it.

such as:

NEC has ADS library for its transistor, but the library doesn't have 2sc3358, it has 2sc3357. You can download the library.

hi tony.I know that NEC site have library,but i need to NEC2C3358.i couldn't find any data sheet with equivalent circuit's 2sc3358.how can achieve to this transistor data sheet with equivalent circuit (namely capacitances and inductances of internal)?

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hi tony.I know that NEC site have library,but i need to NEC2C3358.i couldn't find any data sheet with equivalent circuit's 2sc3358.how can achieve to this transistor data sheet with equivalent circuit (namely capacitances and inductances of internal)?

there is not anyone help me?how achieve to nonlinear model of nec 2sc3358 transistor?

This website show 6 possible equivalents for the 2SC3358 http://alltransistors.com/transistor...ansistor=14541
There is a link that try and match most parameters and give possible substitutions.
Maybe it will be easier to find models for them

Why you have to use this transistor ? As I saw, it's a old type mesa type transistor and I believe there are higher performance mates...

thank you E-design.
hi BigBosse.because my circuit is designed in terms of this transistor and i must don't change circuit's element values.I want simulate with ADS.