What's the difference between self-excited oscillation and sine wave generation circuit? Why is AF = 1 and AF = - 1

What's the difference between self-excited oscillation and sine wave generation circuit? Why is AF = 1 and AF = - 1

Self excited oscillation is an oscillation phenomenon that occurs outside the passband. Because there is a phase shift in the amplifier circuit, and generally speaking, the phase shift starts from DC and gradually becomes larger (\ \ X08 personal experience), and beyond the passband, the phase shift will become larger faster. If the phase shift is 180 degrees and AF is 180 degrees (i.e. - 1), the feedback will form a positive feedback and oscillate
Sine wave oscillation is an oscillation phenomenon within the passband. Within the passband, the phase shift is usually relatively small (especially in the frequency range far away from the cut-off frequency in the passband, because the phase shift and cut-off frequency are related to the position of the pole). At this time, the phase shift can be ignored, so in order to form oscillation (positive feedback), AF must be 1

The balance condition of the feedback sine wave oscillator is ()

Besides the amplitude balance condition, the phase balance condition must be satisfied
φA + φF = 2nπ （n = 0,1,2,…）
A is the phase shift of the amplifier;
F is the phase shift of the feedback network

What is the general composition of a sine wave oscillator

Sine wave oscillator is LC oscillator composed of inductance (L) and capacitance (c), RC oscillator composed of resistance (R) and capacitance (c), or composite oscillator composed of these three elements. The parameters of these three elements determine the oscillation frequency, and then combined with amplifying circuit and positive feedback circuit to form a practical oscillator with specific frequency and amplitude

As shown in the figure, it is a parallelogram made up of two identical right triangle iron sheets. What is the height of the parallelogram iron sheet?

Figure not inserted

What are the strange phenomena in life

There are two rainbows

1. The key sequence is 2 x to the power of Y. The result of 4 is ()

The result of the key sequence of 2 x to the power of Y 4 is (2 ^ 4 = 16)

Let a and B be matrices of type n * m and m * n respectively, and C = AB be invertible matrices. It is proved that the set of column vectors of B is linearly independent

It is proved that R (c) = n is known from C
So n = R (c) = R (AB)

In the triangle ABC, ab = AC, BAC = 80 degrees, P is a point in the triangle, PBC = 10 degrees, PCA = 30 degrees

Make ∠ pad = 10 ° in ∠ PAC, connect PC to D, and connect BD. then ∠ DAC = 30 ° = ∠ PCA, so Da = DC, BD bisection ∠ ABC, ∠ abd = ∠ CBD = 40 °. ∵ ∵ ∵ PDA = ∠ DAC + ∠ PCA = 60 °; ∵ PDB = ∠ DCB + ∠ CBD = 60 °. ∵ PD bisection ∠ ADB; and ∠ pad = ⊿ PAB = 10 °, that is pa bisection ∠ bad, so point P is ∠ a

Finding the zeros of the function F X = x ^ 3-4x
Answer it in ten minutes, gods~

The factorization is x (x + 2) (X-2) and the zeros are - 2,0,2

How to find the angle of line and plane with space vector

The angle between the oblique line and the plane normal vector is complementary to the actual line plane angle
Generally speaking, if the angle between COS & lt; oblique line and the normal vector of the plane = a (that is to say, the cosine value is actually the cosine value of the angle between the oblique line and the normal vector of the plane, but it is converted into the sine value of the line plane angle according to the induction formula), write the line plane angle = arcsina