Find the RC active filter design 100 points, additional points for satisfaction .

The ratio of the input-output of the filter is the gain. Its function is to allow signals in a certain frequency range to pass through signals outside the frequency range that are suppressed or sharply attenuated than the frequency range. Depending on the frequency range, it can be divided into four types: low-pass, high-pass, band-pass, and band-resistance.

Generally speaking, the higher the order n of the filter, the faster the rate of amplitude-frequency characteristics, but the more nodes of the RC network, the more cumbersome the calculation of component parameters and the more difficult the circuit debugging. However, any higher-order filter can be cascaded with a lower-order filter.

Active filter design software** Operating environment win9x win2000 winxp win2003 finishing time 2008-5-9 15:48:27 software star software language.

Enter the frequency you want, and the requirements, it will automatically calculate the components you want, and automatically generate the active filter circuit diagram you want.

I've answered this question once.

Please refer to My Parameter Settings.

Refer to the digital and electric model and electricity textbook ...

Check online to see if there are any chips that can be used.

Let's first understand the function and circuit diagram of the transistor.

You can refer to the digital and electrical model and electrical textbook.

You can check online to see if there are any chips that can be used.

But I suggest that you first understand the function and circuit diagram of the triode.

Here's how it works.

Won't post a picture, here.

Hope it helps.

It is recommended that you don't put too much effort into analog filtering, digital filtering is very mature, and sooner or later it will replace ordinary filters.

In the RC circuit, the capacitor and the resistor R are connected in series, and the filtering effect is mainly obtained by the different voltage divisions of the two components at different frequencies.

1) If the low frequency W is small, and the capacitive reactance of 1 Wc is larger than the resistance R, the partial voltage obtained from the capacitor is relatively large.

2) The high frequency W is large, and the capacitive reactance of 1 Wc is smaller than the resistor R, and the partial voltage obtained on the capacitor is small.

Therefore, the output of the low-pass filter circuit is the voltage on the capacitor, and the low-frequency divider is large and the high-frequency divider is small; The high-pass filter output is a resistive voltage with a small low-frequency divider and a large high-frequency divider.

Background: Filtering is an important concept in signal processing. Filtering is divided into classical filtering and modern filtering.

The concept of classical filtering is an engineering concept based on Fourier analysis and transformation. According to higher mathematical theory, any signal that satisfies certain conditions can be regarded as the superposition of an infinite number of sine waves. In other words, the engineering signal is formed by the linear superposition of sine waves of different frequencies, and the sine waves of different frequencies that make up the signal are called the frequency component of the signal or the harmonic component.

A circuit that only allows signal components in a certain frequency range to pass through normally, but prevents another part of the frequency components from passing through, is called a classical filter or filter circuit.

In fact, any electronic system has its own frequency band width (a limitation on the highest frequency of the signal), and the frequency characteristics reflect this fundamental characteristic of the electronic system. The filter is an engineering application circuit designed according to the influence of circuit parameters on the frequency band width of the circuit.

The basic principle of using analog electronic circuits to filter analog signals is to use the frequency characteristics of the circuit to select the frequency components in the signal. In frequency filtering, the signal is regarded as an analog signal composed of sine waves of different frequencies, and the signal is filtered by selecting different frequency components.

When higher frequency components of a signal are allowed to pass through a filter, this filter is called a high-pass filter.

When lower frequency components of a signal are allowed to pass through a filter, this filter is called a low-pass filter.

When only components of a signal in a certain frequency range are allowed to pass through a filter, this filter is called a bandpass filter.

The behavior characteristics of an ideal filter are usually described by an amplitude-frequency characteristic diagram, also known as the amplitude-frequency characteristics of a filter circuit.

For filters, the frequency range where the gain amplitude is not zero is called the passband, or passband for short, and the frequency range where the gain amplitude is zero is called the stop band.

r and c and bias are different; L and C are reversed.

The frequency copy rate range of the LC filter application.

1kHz due to limited BAI

in which inductive.

duq value, the frequency response as of zh

The area is not steep enough.

1. Compared with LC filters, RC filter DAO is easier to miniaturize or integrate, and the relative volume of LC is much larger;

2. The RC filter has loss, and the LC filter can theoretically have no loss;

3. The volume of RC is smaller than that of LC, and the cost is the bottom;

4. RC is used in low-frequency circuits, and LC filtering is generally used in high-frequency circuits;

5. The resistance in RC filtering consumes a part of the DC voltage, and R cannot be used in circuits with low current requirements. RC is small in size and low in cost. The filtering effect is not as good as that of LC circuits; LC filtering is mainly due to the small resistance of the inductor and the small DC loss.

It has a large inductive response to alternating current and a good filtering effect. The disadvantage is that it is large and bulky. High cost.

It is used in demanding power supply circuits.

6. The more filtering stages, the better the effect, but the higher the loss and cost, so it is not recommended to exceed 3 levels;

7. RC filters are generally used in combination with operational amplifiers to form active filters, mostly as filters for low-frequency signals. For example, it is used as a loop filter in a phase-locked loop.

The LC filter circuit has good stability, low sensitivity, high cost and large size; RC filter circuits are low cost and small in size, but due to the high frequency characteristics of capacitors, they cannot be used in too high frequency circuits. All of the above is for passive filters.

1. Passive filter and active filter can literally be seen that one only needs RC; The other one needs to have a power supply, and of course this will be done with a set of corresponding circuits.

2. The passive filter will attenuate, and the active filter can also be improved.

3. The frequency range of filtering is different, and the active one is more flexible, narrow or wide, etc.

4. The impedance matching of passive filters is easy to calculate, while the active filters are slightly complicated. ......

This is a simple low-pass filter circuit.

It is an RC filter circuit, which should be a low-pass filter.

1. R is limited by the impedance of the circuit, and the impedance of a typical high-frequency system is 50, so R cannot be too small, otherwise the circuit cannot be driven;

2. Affected by the distribution parameters, the wiring capacitance cannot be zero and inaccurate, so the capacitance cannot be too small;

3. The gain of the active device at the cut-off frequency must be 50 times greater than the gain of the filter, which is also a serious constraint;

Therefore, the highest frequency is not high, RC is usually used for low-frequency filtering, and LC filter should be used for high-frequency filtering.