# What is Bandpass filter: Definition and 27 Discussions

A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range.

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1. ### Finding R and C values for an active second-order bandpass filter

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 circuit layout which can be seen below I found my transfer function so that I could calculate...
2. ### Visualizing Series Bandpass Filters: A Graphical Approach

this is the circuit this is the theoretical graph
3. ### Engineering Bandpass filter Maths help please

Hello ,am posting this thread because i need help with 1Q , i was told by my tutor to measure Vo and Vi over the range of frequencies 1khz to 100khz , but i have no idea how to do that ,am not very good at maths and that's why i been really struggling to do it , i have tried doing it but am 100%...
4. ### Ladder-like bandpass filter theoretical analysis problem

I consider the band-pass filter of the following configuration (the ##u_m## is a voltage controlled voltage source): The transfer function is $$K_1(p)=\hat{U}_o(p) = \frac{p}{RC(p+1/RC)^2} = \frac{\omega_c p}{(p+\omega_c)^2}, \quad \omega_c=\frac{1}{RC}.\qquad (1)$$ Now I connect ##n## such...
5. ### Sallen-Key Filter Homework: Tips to Improve Peak Voltage

Homework Statement Homework EquationsThe Attempt at a Solution I worked out the Bandwidth at: 1500Hz so therefore Fh should be 4050Hz and Fl should be 2550Hz Could someone give me any tips as to how correct my key is? with respect to the Bode plot on the sinusoidal output of my design the...
6. ### I Predicting the decay time of a resonant bandpass filter

In a typical resonant bandpass filter, resonance is set as none at 0 and full at 1, such that the filter rings infinitely at 1 and not at all at 0. If there is a two-pole resonant bandpass filter, with an impulse excitation to a maximum amplitude of "1" and a resonance setting between 0 and 1...
7. ### Trouble with getting AM receiver to work

Hello, I have assembled the following AM radio reciever circuit: Purpose of the circuit: To receive AM radio signals and provide the output audio of these signals ( demodulated ). Circuit elements: L ~ 1.5mH , C ~ 300pF , Amplifier IC: LM324N , Diode: 1N4004 ...
8. ### Interpolating data of a bandpass filter with Q=10.4

Hello everyone. I'm trying to interpolate the data taken (frequency in Hz vs A in dB) from a bandpass filter with Q = 10.4. The problem is that I'm not entirely sure about the transfer function that I should use to interpolate it. I'm trying to extrapolate the peak frequency, Q factor and...
9. ### Optical Bandpass filter specification

Hello, For optical bandpass filter specification, what do they mean by 0.1nm bandpass filter? What is the equivalent bandpass frequency range of the filter? Thank you.
10. ### Zero phase shift Op-Amp bandpass filter design

Homework Statement "design a band pass circuit having a midband gain of 20 dB with -3 dB frequencies at 20 Hz and 20 KHz the amplifier should not produce any phase shift." does midband gain strictly apply to voltage gain (because that's how i look at it)? I was going to use a common collector...
11. ### Bandpass filter design - wideband

I'm trying to design a bandpass filter with a BW of 50MHz in LTSpice, however my simulations aren't coming out as I'd like. I'm using the frequency transformation method, with a centre frequency of 2GHz., fractional BW 2.5%. I'd like a wider passband, however I can't seem to get away from the...
12. ### Center Frequency and Bandwith of Bandpass Filter?

Homework Statement Determine the center frequency and bandwidth of the bandpass filter. Homework Equations center frequency of bandpass filter = ωc occurs when the magnitude of H = 1 H = V0/Vs Center frequency occurs when Im(Z) = 0 Zc = 1/(jωC) = 1/s ZL = jωL ZR = R I don't know a formula...
13. ### Engineering Where is the bandpass filter in this circuit?

Homework Statement I am doing a project on the Elenco AM/FM superheterodyne radio kit. I have been stuck for ages trying to figure out how the two common emitter amplifiers are tuned to filter out anything that is not around 455 kHz. I tried to find a bandpass filter, or a high-pass and a...
14. ### Bandpass Filter Homework Statement

Homework Statement A simple way to build a bandpass filter is to filter the output of an RC highpass filter with an RC lowpass filter, as shown on the left in the diagram below. The isolation buffer is a circuit element that keeps the two circuits isolated so they behave as they would on their...
15. ### Frequency Division Multiplexing. FM SSBSC system. Bandpass Filter

Homework Statement Due to its bandwidth and power efficiency, SSBSC is commonly used in Frequency Division Multiplexing (FDM) systems. FDM systems are used to combine a number of separate information channels into a single transmission. Each channel uses a separate carrier frequency and the...
16. ### Need guide to design FIR bandpass filter using calculation or MATLAB

Homework Statement hey there.. I really hope u guys can help me extracting the important element from the question below; A signal is sampled at the sampling rate of 10kHz. The signal has useful signal content between 1kHz and 2.4kHz, and distortion of not more than 1dB is required for...
17. ### Design Op-Amp Bandpass Filter for 500 & 1500 rad/s

Homework Statement Select component values to design for corner frequencies at 500 rad/s and 1500 rad/s. Homework Equations KCL, transfer function The Attempt at a Solution Gain: [1] G = 1 + \frac{R_{A}}{R_{B}} Voltage division: [2] V2 = V1\frac{R_{2}}{R_{2}+1/sC_{2}}...
18. ### Simple digital Bandpass Filter confusions

Lets assume I have a signal that exists in time and it has an unit impulse at t=5, I only want to filter out that portion of the signal. So I plan to design a passband filter to filter the signal out at t=5. This is where I get confused, my passband filter exist in frequency so how is that...
19. ### Resonate Frequency of Bandpass Filter

Homework Statement See attached. Can somebody explain how the resonant frequency w0=1/RC. I worked it out by setting imaginary Z(s)=0. The answer I get is j√2 which is obviously wrong. Is it wrong to calculate the resonant frequency in this manner in this case? Homework Equations...
20. ### Difference between Optical bandpass filter and normal/electrical bandpass filter

Hi there, I am very new to optical domain, and I am only used to the common bandpass filter that we use on circuits, those RLC and OP-AMP based bandpass filter. I went through few books and can't really find the difference, do anyone have any link regarding this issue or idea about this...
21. ### RL Bandpass Filter: Impedance & Voltage Signal

Does an RL low pass and high pass filter need to have the same impedance in the circuit as to the source impedance to work properly. I put an inductor in series with the source with a resistor to ground as the low pass, and a resistor in series with the source with an inductor to ground as a...
22. ### Bandpass Filter component calculations.

Once again I'm going through all my old homework and taking the notes I should have done in the past, and I am stuck on calculating the components on a Bandpass filter. How would I go about this. I have the answers I just want to know how to find them. Thanks...
23. ### Design Bandpass Filter 300Hz-3000Hz | 8V Out Voltage

Homework Statement I have to design a bandpass filter (300Hz to 3000Hz). I have been given a variety of resistors and capacitors to work with. Oh yes, another thing is that i need an output voltage that's <8V. I'm cascading it with another IC. Capacitors - 10nF, 0.1µF, 0.33µF, 0.47µF, 1µF...
24. ### Build a RC bandpass filter to pass only 60Hz

I'm wanting to build a RC bandpass filter to pass only 60Hz. But I do not know what capacitors and resistors to use. Can anyone tell me what capacitor and resistors I should use?
25. ### MATLAB Finding Realistic Data for Bandpass Filter Program Testing

I want to work on a bandpass filter program, but I'd like some realistic data to try it on. There's got to be something on the web to write/test programs with. Any suggestions?
26. ### Design idea about Microstrip bandpass filter

Hi everyone, I am recently starting a new project on designing a 2.4GHz microstrip bandpass filter, but there are so many ways doing this, which method is better for microstrip? hairpin-filter? interdigital filter? or combline filter? Is there any website or material anyone can recommend which...
27. ### Maximizing Bandpass Filter Bandwidth: Practical vs Theoretical Approaches

Cutoff Freq. = 1/2piRC. Theoretical bandwidth = 5000 - 1000 (APP) = 4000 But when I do it practically Or simulate as in the pic Bandwidth = 10000(Around). I asked the teachers in my college they say I did the practicals wrong. Those teachers gave signatures to everyone in the class even...