# The role of ltc1566 low-pass filter

①What is the function of the filter in the circuit

The function of the filter is to effectively filter the frequency point of a specific frequency in the power line or the frequency other than this frequency point, Obtain a power signal of a specific frequency, or eliminate the power signal of a specific frequency.

Using this feature of the power filter, a square wave group or complex noise after passing through the power filter can be turned into a sine wave of a specific frequency.

Filters of high-power power supplies such as Satons, UBS, frequency converters, etc. will generate a large amount of harmonic current, and such filters need to use active power filter APF. APF can filter out the 2~50th harmonic current.

(1) The role of the ltc1566 low-pass filter extended reading

The power filter cannot have an electromagnetic coupling path:

① The power input line is too long;

②The input line and output line of the power filter are too close.

Both are incorrect installation methods. The essence of the problem is that there is an obvious electromagnetic coupling path between the input wire of the filter and its output wire.

In this way, the EMI signal existing at one end of the filter will escape the suppression of the filter and be directly coupled to the other end of the filter without being attenuated by the filter. Therefore, the filter input and output must be effectively separated first.

In addition, if the above two power filters are installed inside the equipment shield, the EMI signals on the internal circuits and components of the equipment will generate EMI on the (power) end leads of the filter due to radiation. The signal is directly coupled to the outside of the equipment, so that the equipment shielding loses the suppression of EMI radiation generated by internal components and circuits.

Of course, if there is an EMI signal on the filter (power supply), it will also be coupled to the components and circuits inside the device due to radiation, thereby destroying the suppression effect of the filter and shield on the EMI signal. So it doesn’t work.

②What is the function of the filter

It is a device used to eliminate interference noise, and the input or output is filtered to obtain pure direct current. A circuit that effectively filters a frequency point of a specific frequency or a frequency other than the frequency point is a filter, and its function is to obtain a specific frequency or eliminate a specific frequency.

③ Where is the low-pass filter generally used? What is the function of the low-pass filter?

The role of the low-pass filter in signal processing is equivalent to other Domains such as the role of moving averages in finance.

The low-pass filter concept takes many different forms, including electronic circuits (such as hiss filters used in audio equipment, digital algorithms to smooth data, sound barriers, image blurring, etc.) Both tools provide a smooth form of the signal by removing short-term fluctuations and preserving long-term trends.

Butterworth filter is a design classification of filters that uses a Butterworth transfer function, which has There are various filter types such as high-pass, low-pass, band-pass, and band-stop.

Butterworth filter has stable amplitude-frequency characteristics inside and outside the passband, but has a longer transition band. It is easy to cause distortion on the transition band.

(3) The role of the ltc1566 low-pass filter extended reading

The low-pass filter allows the transition from DC to a certain The signal with cut-off frequency (fCUTOFF) passes through. The high-pass and band-pass coefficients of the second-order transfer function of the general filter are both set to zero, that is, a second-order low-pass filter transfer formula is obtained:

For high At the frequency of f0, the signal falls off at the rate of the square of that frequency. At frequency f0, the damping value attenuates the output signal. You can cascade multiple such filter sections to get a higher order (steeper dip) ) filter. Assume that the design requires a fourth-order Bessel low-pass filter with a cut-off frequency of 10 kHz.

The roll-off frequencies of each section are 16.13 and 18.19 kHz, respectively, and the damping values ​​are 1.775 and 0.821, and the high-pass, band-pass, and low-pass coefficients of the two filter sections are 0, 0, and 1, respectively.

It can be implemented using these two filter sections with the above parameters The required filter. The cut-off frequency is the frequency point at which the output signal is attenuated by 3dB.

The function of the wave circuit is to allow signals in a certain frequency range to pass through, while blocking or weakening signals in other frequency ranges. Yes The source filter circuit is composed of resistors, capacitors and integrated operational amplifiers, also known as active filters. Active filters can also amplify the signal while filtering, which is impossible for passive filters.

According to the different frequency range of the filter circuit to pass or prevent the signal, the filter circuit can be divided into low-pass, high-pass, band-pass and band-stop circuits. The design and simulation research of active low-pass filter circuits are discussed. The source low-pass filter circuit can pass the low-frequency signal and suppress or attenuate the high-frequency signal.

④ Briefly describe low-pass.The role of wave filters and high-pass filters.

Filter different frequency bands of the signal, low pass filter the high frequency part of the signal spectrum, high pass vice versa.

⑤ What is the function of the filter

The filter, as the name suggests, is a device that filters waves. “Wave” is a very broad physical concept. In the field of electronic technology, “wave” is narrowly limited to specifically describe the process of changing the value of various physical quantities with time. Through the action of various sensors, this process is converted into a time function of voltage or current, which is called the time waveform of various physical quantities, or a signal. Because the independent variable time’ is a continuous value, it is called a continuous time signal, and it is also habitually called an analog signal. With the emergence and rapid development of digital electronic computer (generally referred to as computer) technology, in order to facilitate computer processing of signals, a complete theory and method of transforming continuous time signals into discrete time signals under the guidance of the sampling theorem has been developed. That is to say, the original signal can be expressed only by the sample values ​​of the original analog signal at a series of discrete time coordinate points without losing any information. Since the concepts of wave, waveform and signal express the changes of various physical quantities in the objective world, Nature is the carrier of all kinds of information that modern society depends on. Information needs to be spread, relying on the transmission of waveform signals. The signal may be distorted due to the existence of the environment and interference in every link of its generation, conversion and transmission, and even in quite a few cases, this distortion is so serious that the signal and the information it carries are distorted. buried deep in the noise.

⑥ Principle and function of low-pass filter

The capacitor can pass high frequency and block low frequency, and can filter out interference signals and clutter. It is enough to use this characteristic of the capacitor. To know how to calculate the cut-off frequency, f=1/2*3.14*RC

⑦ The main function and function of the filter

⑦ The p>

filter, as the name suggests, is a device that filters waves.

“Wave” is a very broad physical concept. In the field of electronic technology, “wave” is narrowly limited to describe the process of changing the value of various physical quantities with time.

This process is converted into a time function of voltage or current through the action of various sensors, which is called the time waveform of various physical quantities, or a signal.

Filtering is essentially the process of extracting the information carried by the original signal from the signal distorted and polluted by noise.

What is the use of low-pass filter?

“(7) The role of ltc1566 low-pass filter extended reading”

Power filter is a filter circuit composed of capacitors, inductors and resistors.

The filter can effectively filter the frequency point of a specific frequency in the power line or the frequency other than the frequency point to obtain a power signal of a specific frequency, or eliminate the power signal of a specific frequency.

⑧ What is the role of the RC low-pass filter?

The essence of the RC low-pass filter is a low-pass filter, and now RC is added to illustrate it It is composed of resistors and capacitors, which is the simplest form of filter composition. A low-pass filter is a type of filter. It is a signal selection circuit that allows signals below the cutoff frequency to pass, but signals above the cutoff frequency cannot pass. It has functions in circuits such as instruments, audio, and signal processing. It can realize the selection of signals according to frequency and avoid the interference of high-frequency signals.

⑨ The role of the low-pass filter in the phase-locked loop

The low-pass filter in the phase-locked loop is actually a loop filter. Component resistors, capacitors or operational amplifiers.
The function is to pass the low-frequency signal, filter out the high-frequency component of the error voltage, and take out the average voltage to control the VCO.
It can improve the spectral purity of the control voltage and improve the system stability. At the same time, it adjusts the parameters of the phase-locked loop, the stability of the output signal, the spectral purity, and the locking time. . .

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