Day 24

Transfer Function：

Use FreeMat to graph a transfer function. 

Codes

Graph

Signals with Multiple Frequency Components

In this lab, we calculate the magnitude response of an electrical circuit and use this information to refer the effect of the circuit on some relatively complex input signals. In particular, we will apply a signal composed of multiple sinusoidal waves of different frequencies and a sinusoidal signal with a time varying frequency ( a sinusoidal sweep).

When the frequency is low, the capacitor is open, the voltage cross R2 is half of Vin. When the frequency is high, the capacitor is short, the voltage cross R2 is 0.

Calculate the theoretical phase shift at different frequency.

Input graph. A custom waveform, 20(sin(1000πt)+sin(2000πt)+sin(20,000πt)) and sinusoidal sweep function, was created. 

Used Analog Discovery to measure Vin and Vout in the circuit.

Sweep wave.

When the wave at 500 Hz

.
When the wave at 1000 Hz.

When the wave at 10K Hz.

Output and the input voltage has some phase shift.


In second part of lab, the input voltage, sinusoidal sweep, has frequency 100Hz to 10Khz in 20ms.

The Vin and Vout rise and fall have same rate, but they are not phase shif.