Questions tagged [band-pass]

Bandpass is an adjective that describes a type of filter or filtering process; it is to be distinguished from passband, which refers to the actual portion of affected spectrum. Hence, one might say "A dual bandpass filter has two passbands." A bandpass signal is a signal containing a band of frequencies not adjacent to zero frequency, such as a signal that comes out of a bandpass filter.

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Designing bandpass filter for audio amplifier

I am a 3rd year engineering student currently working on a project where I need to basically make an ultrasensitive metal detector. Basically, I need to create an alternating magnetic field by ...
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Cheap Audio Equalizer board converted to seperate outputs

You can get a cheap ten band equalizer board for about $10. I was inspired by circuit bending and modifying pre-made circuit boards. So I wondered if an equalizer such as this could output each of its ...
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RC filters in JFET negative feedback

I saw a useful answer about JEFT negative feedback here and so I thought I'd ask for some help too!! I'm attempting to create a JFET gain stage that uses a filter in a negative feedback loop to boost ...
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What is the relationship between bandwidth in the context of a passable range of frequencies vs bits per second being transferred

I am in school for electrical engineering. I am still in introductory circuits. I have seen bandwidth used in the context of a Bode plot, which was describing the range of frequencies that a filter ...
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Quality factor of capacitor and inductor in filter design

I designed my desired Chebyshev filter with these parameters (F0=100 MHz, BW=10 MHz, attenuation=40 dB at 20 MHz). The results are acceptable. After changing the quality factors of inductors and ...
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How to improve a bandpass filter design

I want to design an active RC bandpass filter to filter out frequencies between 5MHz to 10MHz for a radiation detection circuit. I am using LTspice for the circuit simulation. I have used a cascade ...
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Bandpass filter test results not same as simulated results

I am designing a 40 kHz bandpass filter for a university project involving a portable ultrasonic device. I have designed a 40 kHz filter using the Linear Technology Filter Design Tool with a single ...
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Gain and phase margin of multiple feedback bandpass filter

I designed a multiple feedback bandpass filter using the Analog filter wizard. The design is purely education therefore I used ideal op-amp. Fc = 50KHz; DC gain = 6dB; Q = 5; I followed the ...
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Multiple Feedback Band Pass Filter Noise

I designed a multiple feedback filter using the analogue devices filter wizard. I have never designed this type of filter therefore I followed up by reading about it and manually calculating the ...
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My Chebyshev filter band pass filter produce tiny values

I am using a Chebyshev band pass filter: Fs = 50 wc =[0.1,0.9] Ap = 0.025 filter_order=2 z, p = signal.cheby1(filter_order,Ap, wc, 'bandpass',analog=True) The ...
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Filtering Frequency Peaks of Sound File

I'm looking into using a 7 second long .wav sound file, and turning on an LED for 0.5s once a 500 Hz peak is detected. I have looked into several methods on how to achieve this. My main idea was to ...
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Loop Filter Bandpass Jitter Characteristic in PLL

I was watching some PLL video lectures by Professor Elad Alon, and he explains why intuitively the jitter transfer function of the loop filter to the PLL output has a bandpass characteristic. He says ...
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Very high frequency band pass filter

I designed a band-pass filter. I set the center frequency to 90 MHz. When I do an AC analysis, I see the filter graph I want, but the transient analysis results are not what I wanted. I'm giving a ...
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How to choose digital potentiometer bandwidth for filter?

We want to use a Digital potentiometer for an active bandpass filter. But we do not know how to choose the bandwidth of the potentiometer. The center frequency of the filter will be 90MHz. Should I ...
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PSpice and calculations don't add up for an active band pass filter

I designed a basic active band pass filter and used these equations to come up with a center frequency of 29.9 kHz: $$f_0 = \frac{1}{2\pi\sqrt{(R_1||R_2)*R_2*R_3*C_1*C_2}}$$ In PSpice, it looks like ...
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LC Topology for band-pass filters

I, as a beginner, am looking to design a passive band-pass filter for a crossover speaker system. This project that I am doing has the following specifications: The filter should be a Butterworth ...
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Frequency response of a low-pass, band-pass, and high-pass adder circuit

I'm doing a project and one of the steps consists of filtering a signal through a low-pass, band-pass and high-pass filter. All the filters are Sallen-Key with a passband gain of 1. The pass-band ...
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Difference in Bode plot with table and Bode plot in Matlab

I am trying to generate a Bode plot for a transfer function of a high pass circuit. It's part of a solution to another question but this is the part that is confusing me. I have a transfer function: ...
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What is the transfer function of this bandpass filter?

I have this bandpass filter for which I'm trying to get the transfer function. The amplifier is not idead and has an open-loop gain of 100k and a gain-bandwidth product of 10MHz. I tried everything ...
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Constant failure in bandpass filter simulation

some of you probably remember my last question, but I like to reiterate: I created a bandpass filter with the help of the online tool FilterWizard, which should block below 30 kHz and above 300 kHz; ...
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Is there a way to further optimize this band-pass filter?

Is there a way to further optimize this band-pass filter created by FilterWizard so that it completely blocks below 30kHz and above 300kHz? I played a little with the numbers and found that (in this ...
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Why is my active passband filter (LP and HP Butterworth filters in series) not working?

I did each filter alone and they work fine, but when they are made together to form a bandpass filter with the same components I used they don't work. The output on the oscilloscope is a very weak ...
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Why is my narrow bandwidth multiple feedback active bandpass filter oscillating?

When I put the following narrowband active bandpass circuit on a breadboard, using a MCP601 single-supply CMOS op-amp, it just oscillates at about 339 kHz with a Vpp of about 1.36 V at a supply of 5 V....
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What's the difference between these two Sallen-Key bandpass filters?

I am thinking about using a Sallen-Key bandpass filter for an audio project I am working on. While trying to understand the circuit, I came across two similar, but slightly different circuits. The ...
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How to calculate multiple pole active filter manually?

For example I want to make a 6-pole multiple feedback topology active bandpass filter that have the specifications of 0.25 db chebychev , that the range of the filter is 2000 hz to 3000 hz. I already ...
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Building a band-pass filter using an op-amp

I am quite new to op-amps but have looked at them in college and have done my own research on them. I am trying to use an op-amp to build a simple band-pass filter which has an in-band voltage gain of ...
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How do you combine 3 existing band pass filters to make a triplexer with 50 Ohm ports?

I have designed 3 microstrip band pass filters that each have a good 50 ohm match at the target frequencies (2 m, 70cm and 13cm bands) and I want to combine them into a triplexer to split one signal ...
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What is the difference between these two Active Bandpass filter circuits?

Both are bandpass filters. The circuit in figure 1 is easy to understand and I can calculate the gain and cutoff frequency without any problem. Regarding the configuration in figure 2, I would like to ...
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Apply S-Domain Notch to Time Signal

I have a signal in time domain which shows an 8Hz oscillation. I've designed a notch (band-stop) filter in frequency domain (S domain) to filter this 8Hz oscillation. Notch design parameters are Width,...
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Help identify ECG signal acquisition using AD2

I have recently got into electronics. I have access to an Analog Discovery 2 (AD2) kit with signal generator and oscilloscope functions. I have been trying to teach myself how to use this equipment ...
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Getting an error in Proteus while simulating the following circuit

I have built a circuit with a series of bandpass filters to detect specific frequencies. While simulating the circuit on Proteus, I was getting the following error. I tried looking for a solution to ...
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Cutoff frequency of RLC band pass and band stop filter

I have found in a website that the cutoff frequencies of a series RLC bandpass and bandstop filters are: $$ f_c = \sqrt{\left(\frac{R}{2L}\right)^2+\frac{1}{LC}}\pm\frac{R}{2L}. $$ This is the link ...
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How to properly design LC bandpass filters?

A little disclaimer. Electronics is a hobby to me so I learn it on my spare time. This leads to certain knowledge gaps that professionals might not have. I want to build a good filter using SMD ...
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Is the resonance frequency actually at the center of the passband of a bandpass filter?

Assume we have the following circuit It is a band-pass filter. There is something I don't get. We know the the resonance frequency is given by \$ f_{Resonance}=\frac{1}{2\pi\sqrt{LC}} \$ and we know ...
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Signal is always attenuated by passive bandpass filter

I'm trying to build a passive bandpass filter with the cutoff frequencies of 0.001 Hz and 10 Hz. It seems that my signal is always attenuated. Why?
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Why does a buffer amplifier change the behaviour of a bandpass filter?

Why does the implementation of a buffer amplifier separating the high-pass and low-pass filter of a bandpass filter affect the transfer function of the bandpass filter? I thought the point of a buffer ...
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Is it possible to acheive a band pass filter with a pass bandwidth sufficient to discriminate AM radio channels, without using an inductor?

I am wondering if it is possible to make a filter circuit that has a high enough Q/small enough pass bandwidth to discriminate AM channels, which are spaced 10 kHz apart in the ~1000kHz range - so ...
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Designing a band pass filter using given specifications

I am trying to design a band pass filter using the below emitter follower circuit : The Specifications for the filter include : $$ Z_{in} = 16k\Omega \\ \text{Current gain} = 35dB \\ \text{3dB ...
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Is the system linear, time-invariant and causal? Does the decomposition property hold? Sallen Key bandpass filter

I have this ordinary Sallen Key bandpass filter: - simulate this circuit – Schematic created using CircuitLab I'm being asked, if the system is linear and/or time-invariant and/or causal. ...
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Band-pass op-amp structure with parallel diodes in feedback?

It's been a while since I've done analog circuit theory, and I'm trying to interpret the 2nd gain stage sub-circuit in this schematic for a guitar pedal: I'm not sure if I'm approaching the circuit ...
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RLC band pass filter — getting the correct phase

Consider the RLC band pass filter circuit: I’m trying to construct this circuit with a maximum of the transfer curve at \$f=5-6\$kHz and bandwidth \$\beta=2\pi \cdot 2\$kHz and so I have chosen a 88k\...
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Coupled Line Bandpass Filter

I am trying to design a microstrip bandpass filter in ADS with a center frequency of 2.4GHz and a fractional BW of 10%. My results from the schematic look great: When I move to the layout and EM ...
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Filter Q factor with 4 pole filter question

I am designing something related to a vocoder and I need 10 filters with certain specifications and I am confused about the required Q factor. The specifications of the 10 filters that are needed are ...
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Why do 2 different online active filter calculators give way different GBW requirements for the same frequency range?

I am confused about 2 different online active filter calculators giving different GBW requirements for the same frequency range. One calculator is giving GBW requirements in the kHz range while the ...
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How does this notch filter work? [duplicate]

I am trying to learn filters. In the following circuit, the author says that negative and positive feedback are used. I couldn't understand what the circuit parts do. Actually I got the negative ...
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Variable band-pass filter for splitting audio signal into separate signals (high and low freqs)

I've been wondering for quite some time how to create a sort of audio splitter. The idea is to get an audio signal (e.g. guitar) at the input, and have two separate outputs, one with the input's low ...
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3 votes
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Detect an IR signal with a photodiode to use it with a microcontroller

I am trying to detect an IR signal with a photodiode to connect it to my STM32F411 and use it as a trigger signal. The signal I send are two pulses at 500 kHz which looks like this: I am using a ...
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Bandpass filter obtained by complementary transformation of lowpass Sallen & Key: what went wrong?

I am considering the following lowpass Sallen & Key filter: My components are the following \$R_1=10 k\Omega\$ \$R_2=10 k\Omega\$ \$C_1=150 nF\$ \$C_2=1.65 nF\$ Now I have performed a ...
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1 vote
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Can I change a frequency band of an EQ board?

Is it possible to change one of the frequency bands of this EQ board? In particular, the low frequency adjuster is 100Hz and I want to make it 60ish Hz. My understanding is that i need to meddle with ...
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Why won't the bandstop filter work in this circuit?

This is the EMG circuit I designed. The cut off frequency of the bandpass is 20-3k Hz. This somehow worked already. But the bandstop filter doesn't show. Why is this? This is the freq-vout graph and ...
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