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AC transfer characteristic with two sources.

Vikram Sharma
Prodigy 70 points

Can anyone tell me how to plot the AC transfer characteristics with two voltage generators (as input) having same frequency but different amplitudes in TINA ?
When ever i try to simulate it shows a error only one input is allowed.  

  • 0
    TI__Intellectual 2290 points

    Vikram,

            Tina only allows the use of one source during AC analysis, to circumvent this you could connect the input source to a voltage controlled voltage source (VCVS) and split the signal in two separate signals and tailor one of the branches as desired. I hope this answers your question.

    Best regards,

    -Marcos.

  • 0
    Prodigy 20 points

    When i try to simulate , possible two are more input signal at different frequency. at same frequency and varies amplitude not possible.

     

  • 0 in reply to pozhilan Samapth
    TI__Mastermind 30715 points

    pozhilan Samapth said:

    When i try to simulate , possible two are more input signal at different frequency. at same frequency and varies amplitude not possible.

     

    Pozhilan,

    The AC analysis is a frequency domain sweep, in which the "frequency" you specify as a property of your voltage source is irrelavant. Any SPICE simulators (TINA included) will ignore that frequency and sweep frequency over the range you specify in the analysis options, usually on a log scale. The entire circuit will be simulated at those swept frequencies, hence only one source is allowed.

    Amplitude in AC analysis is irrelavant as well, because the circuit is linearized at the DC OP. But same frequency/different amplitude is possible with Marcos' method.

    Different frequency implies AC sweep is not the right analysis to be used. A common example is the two-tone test for non-linearity, typically done with a transient analysis.

  • 0
    Genius 5430 points

    Vikram;

    If you do a Transient simulation instead of an AC Transfer Function simulation in TINA, it will allow two or more inputs.

  • 0 in reply to Marcos López - Online design tools
    Prodigy 125 points

    Hi TI,

    In order to trace several transfer functions (with AC analysis) with a single shematic including several op-amp circuits (4 to 6 circuits) and to avoid the error "only one input is allowed", I try a different way using a voltage source as a reference with 2 jumpers (n1 on voltage source + and n2 on voltage source -) on each input.

    Then, for each op-amp circuit, I put jumper n1 on inverting input then jumper n2 on non inverting input. The issue is that simulation for transfer function shows all curves as if they had the same characteristics (same gain, same phase) as if only one schematic was simulated and all the others were the same compared to the first one. But it is not the case as I put different closed loop gain for example.

    What is quite strange is that on another computer, this process is OK and work fine. Curves are different and this method using jumpers for multiple input voltage source is OK.

     

    thank you for your help