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Low Pass Filter Usage and Types


A low-pass filter is the complement, of a high-pass filter; it could be known as a filter that passes the signals with the lower frequency than a cuff off frequency and attenuates signals are signals, which have the higher frequencies than the cutoff frequency. To know the exact frequency of response of the filter, there is need to know about the filter design. Consequently, the low pass filter only allows the low frequency signals to pass from the Fc point, from the 0Hz. The higher frequency is blocked in the process (Shamieh & McComb, 2011).

Low Pass Filter Usage and Types

Low Pass Filter Usage and Types

Low Pass Filter Usage and Types


Low-pass filters are exist in different forms, which also includes the electronic circuits example a hiss filter, which is used in the audio and the anti-aliasing filters, which have the conditioning signals. Conditioning signals are prior to the analog to digital conversation, digital filter for the blurring of the image, acoustic barriers, smoothing set of data and so on. The particular kind of low-pass filter is the average moving operation that is used in the field of finance. The average moving operation can be analyzed in the same way as the low-pass filter.

There is the signal processing technique, which is used for the low-pass filter, however, low-pass filter can provide the smoother form of the signals and the short-term fluctuations can be removed, the low-pass filter can leave the long-term trends. Low-pass filter can be often used as a prototype filter; the filter unity in this case can be impedance and bandwidth.

Electric Low-pass

Moreover, there are the electric low-pass filters that have the modify designs, the low-pass filter can be reject reshape according to the unwanted frequencies, the electrical signals can be accept or pass by the circuit designer. There are the consumer electronics low-pass filters, which are used to control the system of the industries, as referred to the facts, there can be multiple of mathematical operations, example of such operation are differentiation, addition, subtraction etc (Suresh, 2010).


In an electronic low-pass filter, the RC filter have the voltage signals, there are the high frequency in the input signal that are attenuated, the filter have the little amount of the attenuation, which is below the cutoff frequency as determined by the RC constant time. In the similar circuit or the current signals, the capacitor and the resistor, work in the parallel or the similar manner.

Usage of low-pass filter

Electronic low-pass filters are used in the inputs to loudspeakers and subwoofers, the inputs are there so that the high pitches can be blocked, or cannot efficiently reproduce. The radio transmitter also uses the low-pass filter in order to block the harmonic emission that can interfere in the process or the other communication. Many electric guitars have tone knob on the electronic low-pass filter. Constant low-pass filter has another name, an integrator.  Telephone lines, which are fitted with the DSL splitters also uses the low-pass filters, as high-pass filter separate the DSL and POTS signals, by sharing the same pair of the wire, however, low-pass filter is used in sculpting. Sculpting of the sound is created by the virtual analogue and analogues synthesizers.

Ideal and the Real Filters

The low-pass filter, which can be considered as an ideal eliminates the frequencies above all the cutoff frequency, while passing, the response of the frequency is the brick-wall filter and the rectangular function. In the ideal filter, there is no transition region, which is present in the practical filter. An ideal filter can be mathematically recognized or memorized as the rectangle functions can multiply the signals, while considering the frequency domain or convolution or equivalently (Saari, Ryynänen, & Lindfors, 2012).

However, the ideal filter cannot be realize if do not have the infinite, extent in the time. There are may be real ongoing signals, because the function supports the region, which may extend in the past or the future. However, the filter in this case needs to have the infinite delay, so that there could be knowledge about the past and the future, it is important to pre-record the digital signals so that the extension could be known.

Real-time application for the real time, related to the ideal filter cans windowing and truncating the infinite impulse. There could be delay in the signals and this shift of delaying the signals is known as the phase shift. If one wants a greater accuracy then there may be longer delay required.


There are different types of the filters, which get advantages or related to the different responses changing frequency, there are cutoff and roll off frequencies that are determined by the additional attenuation, such frequencies may be higher than the cutoff frequency. The first order filter and the second order filter, have the different ranges or levels of the frequencies, third order filter is roll off at the different rates.

  • https://www.sensorsmag.com/sensors/electric-magnetic/an-introduction-analog-filters-1023
  • https://www.electronics-tutorials.ws/filter/filter_2.html

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1 comment

Taylor Hicken October 20, 2020 - 3:01 pm

I liked it when you mentioned that signals can pass below the cutoff frequency with the help of a low pass filter. It is very important to choose wisely the one that can achieve your expectation since there are so many types of these components in the market. I would like to think if someone is working on an electrical project, he should decide on the right filter that can be useful for his application from a reliable supplier.


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