Tina-TI的傅里叶分析使用疑问

里面的设置参数一大堆。莫名其妙。然后试着用OPA134跑了一下-1倍的反相放大器，然后谐波分布和PDF中完全不同。按照PDF的描述，应该2次谐波明显高于3次。

但是分析做出来确是差不多。。。。

Hi, 你好！

谢谢你使用TINA-TI工具。TINA-TI是TI推出的一套Spice-based的免费电路仿真工具（TINA简洁版本），可进行DC、AC、瞬态、傅里叶、噪声分析等，包含有绝大多数TI的器件波形等，深受广大电子爱好者的欢迎。

对于你这个问题， 请帮忙提供详细信息，如仿真设置、波形等，便于分析。此外，在TINA-TI的帮助栏里，提供了傅里叶分析的使用说明，供你参考。谢谢！

TINA is a Spice-based circuit simulator running in the Microsoft Windows Operating system. It can do circuit DC, AC, Transient, Fourier, noise analysis, etc. TINA can be purchased through the vendor's (DesignSoft) web page located at www.tina.com.

TINA-TI is a simple version of TINA with full functionality in circuit simulation, but less circuit development utilities in the package. Also, TINA-TI contains more TI device models and TI part information. TI distributes TINA-TI free worldwide through www.ti.com/analogelab.

TINA-TI and TINA Design Suite Version Comparison

Fourier Series

The frequency domain characteristics of the transient responses can be examined using Fourier analysis. Fourier Series is obtained by computing the Fourier series of the output function of time, and then calculating the distortion factor from the Fourier coefficients. Harmonic distortion is displayed in units of %. After selecting Fourier Series, this menu appears:

Sampling start time  This determines the instant when the Fourier analysis starts. The default value is the Start of display parameter of the Transient Analysis Menu. You will not be allowed to set a lower value.

Base frequency  Here you must specify the fundamental frequency of the Fourier series. The default value is the lowest frequency produced by any of the generators available in the network with periodic (sinusoidal, general trapezoidal) waveform. Note that the end of the FFT sampling interval is calculated as the sum of the sampling start time and the reciprocal of the base frequency. This value cannot be greater than the Time of analysis parameter of the Transient Analysis Menu. Note, that for best accuracy, it is very important to set the sampling start time for the Fourier Series analysis to after the initial transient has died away.

Number of samples  Sets the number of sampling points for the FFT. Due to the nature of the Fast Fourier Transformation, this number must be a power of 2. Choose the desired value from the menu. The higher the number of samples, the greater is the accuracy—but this increases the computation time as well.

Number of harmonics  This shows how many Fourier coefficients (from 2 to 16) have been used for computing the distortion factor. These coefficients will be displayed on the screen, too.

Format  You can choose from the two usual formats for representing the Fourier coefficients; namely, with absolute value and phase (according to the exponential format), or with the cosine and sine factors.

Calculate  Press this button to calculate the Fourier series using the parameters shown. The Fourier coefficients will appear in an extendible table in the dialog box, and the harmonic distortion will appear below. Whenever you change a parameter on the dialog box, the results table will disappear and you must press the Calculate button again to obtain the results of the modified analysis.

Draw  Press this button to draw the spectrum lines. Note that when you move the cursor over a spectrum line, it assumes a + shape, and the actual magnitude of the spectrum line is displayed at the bottom of the main TINA Window.

Fourier (Frequency) Spectrum

Transient time functions can be examined in the frequency domain with this function. The continuous spectrum is determined by the Fourier transformation of the time response.

After selecting the Fourier Spectrum option, this menu appears:

Number of samples  Sets the number of sampling points for the FFT. Due to the nature of the Fast Fourier Transformation, this number must be a power of 2. Choose the desired value from the menu. The higher the number of samples, the greater is the accuracy—but this increases the computation time as well.

Sampling start time  This determines the instant when the Fourier analysis starts. The default value is the Start of display parameter of the Transient Analysis Menu. You will not be allowed to set a lower value.

Sampling end time  This specifies the termination time of the FFT. The default value (and the maximum allowed value as well) is the Time of analysis parameter of the Transient Analysis Menu.

Minimum and maximum frequencies The minimum and maximum frequencies of an FFT analysis are inherently related to the number of samples, the sampling start, and the sampling end. You can not arbitrarily set these frequencies; however, you can alter them to values that will restrict the range of analysis.

Phase correction  Enabling Phase correction (On) reduces the effect of aliasing which may occur if the waveform contains energy above the Nyquist frequency (half the sampling frequency).

Default diagram view  You can choose among four choices of the curve to be drawn initially: Amplitude, Phase, Real Part, or Imaginary Part. All four curves are immediately available by clicking on the appropriate tab below the curve.

best regards,

Steven