Re: How to simulate reactance in LabView

On Apr 2, 5:10 am, sod mala <x...@xxxxxxxx> wrote:
Hi All,
Thanks for response.
Well, I am trying to simulate effect of inductive load on square wave.
Basically, Square wave has got number of odd harmonics of fundamental frequency. And as Inductance is 2*pi*F*L, it wil act as low pass filter.
So, I want to show&nbsp;by using only LabView software (without any hardware), frequcny spectrum of voltage before applying to Inductor and frequncy response of current through inductor. I expect that current will have not have lot of high harmonics in it's specturm.
I am facing problem to simulate inductive load. How I can simulate 2*pi*F*L, as I am nopt checking for particluare&nbsp;F value but all spectrum.
Should I convert first all signals in Fourier domain?&nbsp;
&nbsp;
&nbsp;

The basic or full versions of Labview are not suited for simulating a
square wave voltage source connected to an inductor. Other tools like
SPICE and National Instruments add-on Simulation module for Labview
are better suited for simulating a square wave voltage source driving
an inductor. Then there is always the old fashioned way of converting
a square wave to a Fourier series and dividing each harmonic of the
series with the impedance of the inductance at the harmonic frequency
to determine the magnitude of the current at each harmonic.

For a 50% duty cycle square wave with an amplitude of plus and minus 1
and no DC component the components of the harmonic series are equal to
zero for even harmonics and are equal to 4/(PI*n) for odd harmonics.
Therefore the magnitude of the current at each odd harmonic is 4/
((PI*n)*|j*w*n*L|).
Which is equivalent to 4/(PI*n*n*w*L). PI = 3.1459, n is the nth odd
harmonic, w = 2*PI*f Or 2*PI/T where f is the fundamental frequency
and T is the period of the fundamental frequency. L is the inductance
in Henries.

There is a very clever demonstration of Fourier series at:
http://www.falstad.com/fourier/
You can use the demo to see what the amplitude oft the harmonics will
be for duty cycles other than 50%. Note you need to have Java
installed on your computer to see the demo. The demo runs runs
flawlessly with Firefox. The page also has links to clever
demonstrations of numerous technical subjects.

Howard
.

Relevant Pages

  • Re: seeking a sound effect creator for short task
    ... like the glockenspiel, but has duration of tone, ... not exactly a square wave, ... both odd and even harmonics with the odd harmonics ... other instrument types." ...
    (rec.audio.pro)
  • Re: Variable Square Wave to Sine Wave
    ... I've read about how you can basically use a low-pass filter to tune ... out harmonics of a square wave and get a sine wave output. ... The low pass filter reduces the amplitudes of the higher harmonics which essentially emphasizes the lower harmonics. ... So an ideal low pass filter inbetween f and 2f of *any* periodic signal will return a sinusoid of frequency f. ...
    (sci.electronics.design)
  • Re: DDS Selection
    ... involved and those have even harmonics. ... triangular wave can be considered the result of a square wave with its ... higher harmonics being attenuated by an integrating filter. ... I can see how an array of resistor values on a shift register can be ...
    (sci.electronics.design)
  • Re: DDS Selection
    ... involved and those have even harmonics. ... triangular wave can be considered the result of a square wave with its ... higher harmonics being attenuated by an integrating filter. ... It's more compact, and you can get 0.1% tolerance resistors, while 1% ...
    (sci.electronics.design)
  • Re: analog multiplier help
    ... > concerned about LO harmonics... ... > square wave LO drive usually improves the linearity of a mixer... ... But since this is multiplying by a square wave, ...
    (sci.electronics.design)