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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lowpass prototype to bandpass filter
Bandpass filter with a center frequency of 10 rad/sec and bandwidth of 20 rad/sec here, wo= is mentioned as geometric frequency that's why I am confused.
The solution in which picture is correct?
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Understanding my basic parallel LC circuit, theory vs results
I made a basic LC parallel circuit.
2.9 µH inductance (measured with a cheap meter)
560 nF capacitor in parallel
following f = 1/((2pi)sqrt(LC)) it should resonate at 124.89 kHz, but was manually ...
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Analysis of an RCL Filter Utilizing a Potentiometer as R
I am trying to calculate the parameters ζ, Q, Fo, Gain (dB), and BW of this circuit. I am confident in the following equations:
Fo = 1 / (2 * π * √(L2 * C1)) ; Q = 1 / (2 * ζ) ; BW = Fo / Q
R2 = R5; ...
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Why isn't the output of this Sallen-Key bandpass filter made with transistors like the output of the op amp version?
I made a transistor Sallen-Key Butterworth bandpass filter using two filter sections for each high-pass and low-pass stage. The output is different from the op amp version.
I know it is possible to ...
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Laser detector circuit with ambient light rejection
I recently asked how to best detect dropped balls via laser detection.
Someone suggested ambient light rejection by modulating the laser and then filtering the photodetector input for that signal.
I ...
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How we change equations in passive bandpass filters?
I tried it myself, but I couldn't understand how the equation ended up in the given form. After bringing it to that form, the cutoff frequency values can be determined, but since I couldn't do that, I'...
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Band-pass filter characteristic parameters and maximum gain frequency
I think I have a big conceptual gap, I hope someone can clarify things to me.
The exercise asks the following:
The analytic expression of the gain \$A_v\; = \; \frac{V_o (j\omega)}{V_{in} (j\omega)}\...
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Is it possible to design a compact antenna for detecting the presence of 50 Hz mains voltage at very short range?
I have a mains cable buried in the wall. I would like to permanently place a small battery powered device on the wall over the cable's location and have the device be able to detect if the cable is ...
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Filter output of a bandpass filter
The following question was asked in GATE 2014 S-1:
A 10 KHz even symmetric square wave passed through bandpass filter with centre frequency at 30 KHz and 3 dB passband of 6 kHz. The filter output is:
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Can we find out RLC Circuit values from just cut-off frequencies?
For example, I've passive BPF series RLC circuit with the information of lower and upper cut-off frequencies. I need to find out the values of R, L and C. Is it possible?
Thanks in advance.
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Two bandpass filters in series, why use different voltage dividers?
I know my question is a bit broad, but I want to ask: Using the single supply configuration, why does the first stage's non-inverting input and second stage's non-inverting input use different voltage ...
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Multiple feedback band-pass filter issue in LT Spice
For a school project, we are tasked to make a band pass filter with a center frequency of 1000 kHz, 1 MHz. Everything works fine below 1.1 MHz. In the picture below, a sine wave with a frequency of 1....
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Band pass filter not filtering?
I am putting together this band pass filter for a guitar project but it doesn't seem to be working. Here is the diagram and the breadboard I'm working with. There is a button there that isn't doing ...
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Baseband circuit is not working as expected
simulate this circuit – Schematic created using CircuitLab
The circuit when printed on PCB, output isn't a bandpass signal as expected. When I am checking the output with CRO across output pin ...
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Design an AGC circuit for microphone using JFET
At the beginning of the circuit, I designed a 20Hz to 20kHz second-order Butterworth bandpass filter circuit, and then I tried to pass the filtered signal through an AGC circuit to achieve a smooth ...
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Transfer Function of Multiple Feedback Bandpass Filter in a specific format
I've been trying to study the Multiple Feedback Bandpass Filter.
I managed to find the transfer function and the natural frequency of oscillation.
$$\frac{V_\text{out}}{V_\text{in}}(s) = \frac{2\...
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Design of a band-pass filter with automatic gain control using a JFET
I have implemented this circuit which is supposed to do AGC and filter out the signal between 20 Hz-20 kHz, but it seems have some problems. The bandpass filter works well, but the agc circuit doesn't ...
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Narrow band band-pass filter design with LM358 op-amp
I am trying to design a narrowband band-pass filter with an LM358 op-amp, single supply 0-5 V. My requirement is a gain of 30 dB at center frequency 4 kHz and 20 dB attenuation at 3 kHz and 5 kHz.
I ...
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Designing an active bandpass filter and selecting R and C values
I have been assigned the task to design an active bandpass filter with a passband of 0.1 to 10 Hz. At these two frequencies, there should be an attenuation of -6dB or more. So far I have selected my ...
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How do I calculate resistor values for a second-order bandpass filter to achieve unity gain at 1 kHz?
The bandpass needs to have a bandwidth of 250 Hz with a centre frequency of 1 kHz.
The values I've calculated so far are R1 = 1000 Ω, R2 = 1000 Ω, C1 = 140 nF, and C2 = 180 nF.
I calculated these ...
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Selecting R and C values for a second-order active bandpass filter
I am using the below second-order active bandpass filter in my breathing rate sensor. I need to have a passband of 0.1 to 10 Hz with -6dB attenuation at these frequencies.
I am not sure what I need to ...
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I am seeing oscillation in this SK bandpass filter circuit even without any input
There is a constant 8-9 kHz oscillation without any input. Otherwise the output is as expected. The open op-amps were terminated as follows negative feedback connection made and non inverting input ...
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LC transfer function
How would I go about deriving a transfer function or expected cut-off frequencies for this LC moveable bandpass filter (wah-wah effect)?
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4th order transfer function
I have a 4th order transfer function. Given transfer function is below.
If given transfer function had been 2nd order transfer function, it would easily be factorization of transfer function like:
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Band-pass filter
How do I ensure that the output voltage is at least 20% below the input voltage in this band-pass filter if the given resistor value is 100 Ω and the input voltage is 2 V?
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RLC band-pass filter
No other values should be changed in this band-pass filter except the L and C.
I was trying to get a natural/resonance frequency the same as the input which is 1 kHz, and the following are the values ...
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Meaning of 'Bessel Filter'
Question
I'll get straight to the narrow point ahead:
I'd like an expert's opinion on the appropriate use of Bessel when considering a specific 4th order bandpass design.
I don't mind a more general ...
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Bandpass filter frequency response not the same as the one taken from analog filter wizard
I want a band pass filter with center frequency 5.5Khz and a passband of 1kHz.
I inserted that into a website and got the frequency response and the components to implement the filter:
I copied the ...
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Why isn't the frequency response of this band pass filter circuit the same as the band pass filter with an ideal op amp?
I'm trying to develop a band pass filter with center frequency 10 kHz:
The frequency response doesn't look good, but when i replace the circuit above with an ideal op-amp, I have the correct response:...
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Derivation of the transfer function of a 5th-order Butterworth LC bandpass filter
I am trying to derive the transfer function of a 5th-order Butterworth LC bandpass filter as seen in the first image. Rs is the source impedance of a signal generator and RL is where a load will be ...
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How to compute the cutoff frequency of a bandpass audio filter?
Much like the title says, I'm wondering how one would compute the cutoff frequency of a bandpass filter given the filter's specs, rather than the usual resistance and capacitance. In other words, how ...
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Complex transfer functions squared
Why is it true that, for a Butterworth filter, we have \$|H_n(jw)|^{2} = H_n(jw)H_n(-jw) = \frac{1}{1+w^{2n}}\$?
I don't understand why the absolute value squared of this complex function has to be \$...
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In Cadence AWR, why do the theoretical values for components yield much lower results than the optimized values?
I used Cadence AWR Design Environment to simulate a bandpass filter from 1.6 GHz to 3.2 Ghz, in both Pi and T formats.
I calculated the theoretical values for each component and put them in the ...
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Band-pass filter simulation
Passive band-pass filter simulation on LTspice. Given: cutoff frequencies Flow= 10 kHz and Fhigh= 22 kHz. The run isn't getting me -3 dB between the pass.
I calculated R and C and put them in the ...
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Bandpass filters using capacitively coupled series resonators
I was wondering how to decide on the gap size for capacitances. Here is the figure from Microwave Engineering by Pozar:
I can calculate the B values, θs and other related stuff. Furthermore, I can ...
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My bode plot does not mach with calculated cut-off frequencies
I have modelled a band-pass filter, but when I calculate the cut off-frequencies and amplitude it does not match with the bode-plot. I am not able to find out what is wrong, hope that someone might ...
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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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