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.

Filter by
Sorted by
Tagged with
0
votes
0answers
47 views

How can I model an optical filter using python?

Say I have an RGB LED which transmit intensity modulated signals, at one symbol transmission I want to send a symbol with all three chips.. Can I just model three bandpass optical filters like RF ...
0
votes
1answer
86 views

Using active BPF to convert a square wave into a sine

I have an inverter that converts 24 V DC to a 48 VAC peak-to-peak square wave with a frequency of 55 Hz. I am then going to use a step-up transformer to output 120 VAC to power some rocket valves that ...
0
votes
2answers
217 views

Low pass filter not working properly

This is the pass band that I'm using to filter some EMG signals through electrodes. When I test it with multisim it works really well as you can see, but when I test it with real equipment (...
1
vote
2answers
86 views

Design a Band-Pass Filter

Recently I came across an exercise which I can’t confirm myself If I’m doing it right. The question itself asked to Design a Band Pass Filter Properties: Lower -3db cutoff-frequency 500Hz Higher -...
1
vote
1answer
58 views

Equivalent model of my (real) transformer

I have created a transformer using a small cylinder (a tube) made of ferrite. The primary coil has \$N_{1}=5\$ turns of coil wire, while the secondary \$N_{2}=50\$ turns. According to a recent ...
0
votes
2answers
56 views

Equivalent circuit of a simple transformer?

EDIT: My question is: How can you translate the first circuit into one that uses simple (linear) electrical elements and, as a result, can be solved using mostly Kirchhoff's laws? I am trying to ...
0
votes
1answer
57 views

Noisy output on active bandpass filter PCB Design

I'm trying to design a 40dB active bandpass filter with a centre frequency of 130KHz and a passband of 80KHz. I don't really know much about filter design so I used the TI filter design tool to design ...
1
vote
0answers
34 views

sallen-key bpf giving low gain after coupled to differential input

I designed a Sallen-key band pass filter where the gain at center frequency is 45.6dB. After feeding it with a sine wave at the center frequency, it amplifies the signal by 45.6dB. However, after ...
0
votes
2answers
103 views

How does the formula for calculating Low and High Frequency in a Band-pass Filter occur?

Our professor told us that we should use the formulas below to calculate the F-high and F-low frequencies that our band-pass filter should have. $$F_\text{low}=\frac1{2π\,R_1\:C_1}$$ and $$F_\text{...
1
vote
3answers
268 views

Differential filters: high pass, low pass, band pass

I am looking to use a band pass filter in an EMG circuit design using the differential signals you receive from an op amp (differential/instrumentation). I have been looking for what is the proper way ...
0
votes
1answer
38 views

Is there a configuration where a circuit acts as Bandpass filter in one direction and Bandstop in other?

I am not an expert in electronics. Hence, I am looking for a broad conceptual answer. Is it possible to a directional Bandpass/Bandstop filter i.e. Bandpass in one port and Bandstop in another.
2
votes
2answers
198 views

What are the differences between active bandpass filter topologies?

I want to use a narrow band active bandpass filter but I found generally 2 topologies as seen below. What are the differences between them?
0
votes
2answers
167 views

Transfer Function Derivation

Where did the following transfer function come from? \$H(s) = -H_o\frac{\frac{\omega_o}{Q}s}{s^2 +\frac{\omega_o}{Q}s + \omega_o^2}\$ \$H_o\$ is the gain at resonant frequency. I'm told it ...
0
votes
2answers
202 views

Active band pass filter + offset

I'm trying to know the fr equation for the following op amp configuration: I have some capacitors values for specific fr frequencies: fr = 34Hz -> C = 33nF fr = 50Hz -> C = 22nF fr = 160Hz -> C = ...
0
votes
1answer
318 views

Audio Equalizer LTSpice Simulation

First, I'd like to say i'm not experienced on circuits, but i'm doing my best to learn. I'm trying to create an audio equalizer which is capable of amplifying low frequencies (20Hz-200Hz), mid ...
1
vote
2answers
227 views

Construction of a Band reject filter

I'm trying to construct something like the band reject filter on the bode graph below. I know that I could make this by using four different filters and adding them up (low pass filter + high ...
0
votes
1answer
71 views

Adjusting the gain on a 4th Order Butterworth Bandpass fIlter gain

I designed a bandpass filter with the TI filter designer tool but I initially designed with a gain of 40 dB. However, I'd like to reduce the gain to 20dB but I'm having issues doing trying to figure ...
2
votes
0answers
111 views

Designing an audio amplifier, problems with bandpass filter

I am trying to build a Audio amplifier for a university project, I think that most of my circuit is done but I have an issue with my filter as my sine signal is not symmetrical after filtering to ...
0
votes
2answers
367 views

Band pass filter bandwidth problem

I am trying to design a band pass filter that allows frequencies between 16,384Hz and 32,768Hz. Firstly I tried to make it using a passive RC band pass filter: Using the formula fc = 1/2πRC, the ...
0
votes
1answer
109 views

How to calculate cutoff freqeuncy of Bandpass filter, given an attenuation dB level (OTHER THAN -3DB)

I know that -3dB is the accepted standard, where the power of the signal is at 50%, and that upper and lower cutoff frequencies are calculated with regards to this value, and there are simple formulas ...
1
vote
1answer
72 views

Why is the input reflection signal very weak?

I built a PCB filter in Class "Band-pass" with center frequency of 2.4 GHz. The board has two SMA's (input 1 & output 2). S(1,2) looks like this: The frequency is good, However, the attenuation ...
1
vote
3answers
148 views

Low capacitance value capacitors in LC bandpass filter

I am going to try to build a Butterworth LC bandpass filter. However, using some online calculators result in some very low value capacitors (sub-1pF). I am thinking that the performance will not be ...
1
vote
3answers
171 views

Band pass filter implementation using 741 op amp

My assignment for a school project on Circuit Theory, is to construct a Band Pass Filter at least 3rd order with a stop band around 20kHz. First things first, I need to design the circuit. I have to ...
8
votes
6answers
1k views

Why is superheterodyning better than direct conversion?

What is the advantage of having the extra stage of IF, extra local oscillator and extra filtering stage and amplification. It just seems like more work and circuitry. Surely the direct conversion to ...
0
votes
4answers
133 views

Tradeoffs for creating higher order butterworth filters

I am working on a bandpass filter to filter the output from a hydrophone. This is my first time designing a filter and using a cookbook from TI, I built a 4th order Butterworth filter with two partial ...
4
votes
1answer
109 views

How to generate this kind of filter?

I've been trying to understand this exercise proposed by my teacher. He asked us to find a combination of 2 ideal filters to generate a filter within the conditions of the image below. (That means, ...
0
votes
0answers
97 views

RC bandpass filter using two port network parameters?

So my assignment is about exploring two port networks and the use of the 4 parameters, now one of the tasks is to design a bandpass filter with cascaded high pass and low pass filters, now I am really ...
0
votes
1answer
207 views

Why Deliyannis bandpass filter with high Q does not have the expected transfer function bode plot

What i need is to design a delyiannis band-pass filter with Q enhancement technique. The theoretical analysis of this technique is referred here in pages 107-112. For those who don't know how to ...
1
vote
1answer
181 views

Parallel RLC bandpass filter Bandwidth incorrect

I have been trying to create a bandpass filter with the cut-off frequency at \$\mathrm{200Hz}\$ and \$\mathrm{4800Hz}\$ I have managed to get the centre frequency to \$\mathrm{2500Hz}\$. The bandwidth ...
1
vote
1answer
240 views

Passive band-pass filter conceptual analysis

I'm trying to chain a high-pass filter and a low-pass passive filter together to form a band pass filter to illustrate how you can combine filters together, but I'm having issues trying to understand ...
2
votes
1answer
392 views

Are these two circuits the same?

Are these rwo circuits the same considering the right hand sides of them where it is parallel for the C&R and C&L(meaning the way i should obtain the frequency response? And for the longer ...
0
votes
1answer
155 views

Ultrasonic transducer actual bandwidth for filtering

I have a pair of ultrasonic transducers with a "Thick Resonant frequency" of 975 kHz ±30kHz according to the data sheet. I did a frequency sweep test where I could see that they performed best at a ...
0
votes
1answer
110 views

Easiest way to find transfer function of a lossless ladder filter after we finish design?

I have completed my Lossless Ladder BPF design, but I don't know how to find the transfer function of the resulting circuit without going through the slow and rigorous process of getting resistances ...
0
votes
1answer
1k views

How do I create a working bandpass filter in LTSpice?

I am attempting to create a bandpass filter in LTSpice. I am fairly new to the program, which is probably contributing to my difficulties. The filter I am creating needs to have a center frequency of ...
1
vote
1answer
68 views

Designing a Band Pass Filter

I need a band pass filter that only accepts frequencies from 1000 to 1400 Hz and then toggles the transistor. It has to work from .1 Vpp to 1 Vpp and rejects anything else. I have been testing this ...
3
votes
2answers
627 views

Designing 4th order Butterworth Multiple feedback bandpass filter

I'm trying to design a 4th order Butterworth bandpass filter using Multiple feedback topology. The design requirements I am trying to achieve for this filter are; Q factor = 10, Av = 11, fc = 100kHz ,...
0
votes
2answers
205 views

What is the difference between a Sallen-Key Band pass filter and a band pass filter?

Am currently doing an assignment on sine wave generation and am using a sallen key band pass filter - i am unsure what the difference between the band pass filter and the sallen-key band pass.
2
votes
2answers
623 views

Parametric Equalizer with State Variable Filter

I'm new to this forum but hope to get some answers to a project I'm working on. I'm trying to build an parametric equalizer with several bands (5 Bass-Bands, 3 Middle-Bands, 3 High-Bands). In the ...
0
votes
1answer
97 views

Digitally selectable filter

I have asked a similar question but I did not get an answer, as it was too specific. So I will build on it but make it a bit more broad spectrum. I would like to make a digitally selectable BPF using ...
0
votes
2answers
248 views

Butterworth bandpass - higher roll-off than expected

I am looking into filters, and i am using FilterLab and MATLAB's Filter designer. I know that i need to make a bandpass filter, with a roll-off of about 48 dB/octave. This is quite high, and i would ...
1
vote
2answers
805 views

Transfer function of a bandpass

i was doing some homework and one thing I had to do was to derivate the transfer function of a given bandPass. I have done it myself but i dont know if it is correct nor if i followed the right path / ...
1
vote
1answer
283 views

First-order analog active bandpass filter with variable center frequency

I've thought about designing an active first-order bandpass filter with variable center frequency and fixed bandwidth, using OpAmps, as a project for an Applied Electronics class. My first try was to ...
1
vote
2answers
357 views

Active band pass filter that looks like a sallen–Key topology filter

I was using the Analog Devices design Wizzard in order to design a band pass filter with theese characteristics: Gain : 23 dB Passband: -3dB at 15 KHz Stopband: -40dB at 40 KHz The filter has 4 ...
0
votes
2answers
434 views

Calculating Phase/Time Delay induced by a 2-pole Bandpass filter? ie. Group Delay?

If you have a two-pole Butterworth bandpass filter described by a particular Q value (Q>0.5) and a resonant center frequency "f", is there any equation that will tell you the phase/time delay induced ...
0
votes
3answers
178 views

Predicting 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, ...
0
votes
0answers
489 views

whats the difference between a cascaded band pass filter and a normal band pass filter (Audio visualizer)

simulate this circuit – Schematic created using CircuitLab currently im building an audio visualizer i would like to know what is the difference between a cascaded 2nd order band pass filter ...
0
votes
1answer
137 views

components used to make a butterworth filter

I doing some amateur radio experimentation and want to create a bandpass filter. I believe that a Butterworth filter would be good because it has a flat frequency response in the pass band. My center ...
1
vote
1answer
59 views

Band Pass Filter Equivalent Components

I am designing a very simple first-order RC band pass filter with cutoff frequencies \$f_l = 0.5 MHz\$ and \$f_h = 4.5MHz\$. I have it pictured below (I'm using 5Spice): This filter acts the way I ...
0
votes
2answers
1k views

I need to design a bandpass filter by cascading passive high pass filter and passive low pass filter

I have a low pass filter with 3db cut off frequency of 200Hz and a high pass passive filter with 3db cut off frequency of 2kHz. I need to design a cascaded band pass filter which will isolate ...
2
votes
2answers
187 views

Band Pass Filter for musical note separation

I have a school project that i need to separate musical notes with filters at least i thought that i can do it with band pass filter, here are the results These are the resistor and capacitor values ...