A filter modifies signals based on their frequency.

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How can I make a band-pass filter?

How can I make a band-pass FIR filter using a PIC microcontroller? I'd like to have the most basic one. I don't know any specifications about a bandpass FIR filter but we can talk about it in the ...
18
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2answers
2k views

Why would you stack a resistor and capacitor on top of each other?

I've inherited an charge amplifier/shaping circuit from my predecessor. When he wanted to make a low-pass filter with current-to-voltage conversion, he had a standard circuit like: simulate ...
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3answers
44 views

bandpass filter

I was wondering why there is a low end pass ; low end stop; high end pass; and high end stop. I have never taken a analog filter class before, But if I want a bandpass filter wouldnt I just want a ...
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2answers
123 views

How to limit the bandwidth of an opamp?

A circuit i made using opamps and transistors causes lots of oscillations (parasitic maybe ?), a solution to that which i find very reasonable is to limit the bandwidth of my main driving opamp so any ...
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1answer
51 views

How to clean up ringing / noise on rising edge of CMOS output?

I am feeding an interrupt input with the output from a CMOS Schmitt inverter. The falling edge of the inverter is nice and clean, But the rising edge is really dirty, and can get downright ugly at ...
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34 views

Estimating Frequency in PLL from phase

Assume I have a digital PLL that outputs phase estimate of the reference signal, however I am wondering can I estimate the frequency of reference signal according to the given phase estimate? I know ...
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2answers
77 views

When is noise a factor in basic analog circuits?

I have a good understanding of circuit theory, but only a few large projects under my belt. In practical applications, at what voltage level does noise really become an issue. Is there any 'typical' ...
3
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0answers
97 views

How do I realize a transfer function with multiple zeros?

I designed a compensation function for a control system in Matlab and now I'm trying to figure out how to build it using op-amps. I thought I might be able to use a couple of Sallen-Key amplifier ...
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0answers
35 views

Photo-interrupter filter and digitizing circuit

I am trying to design a circuit that can filter and digitize a photo interrupter signal. I have the signal from the photo-interrupter (3.3V/ground) connected to a low pass RC filter with resistor ...
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3answers
64 views

Studying electronic filters

I'm studying this filter: And I want to know all the important points in this filter (the math way), can someone help me? What are the trivial points in this filter? My Work, transfer function: ...
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1answer
62 views

Circuit analysis of partial circuit

I want to analyze the cutoff frequencies, order and Qs of filters inside a complicated electronic circuit. Instead of solving equations, as a rookie I find using SPICE a lot easier. However, the ...
0
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2answers
37 views

four-order filter bandwidth and the two-order fileter bandwidth is same? [closed]

I have a two-order bandpass filter, the fc = 10k, bandwidth = 2k. Is the bandwidth changed, if I use this to make a four-order bandpass filter ? if No, why the image
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1answer
78 views

Which part of this circuit plays the role of filtration?

Can anyone say which part of this circuit plays the exact role of filtration and which part plays the role of amplification? How can I find and learn the calculations related to these parts? It's ...
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1answer
80 views

Admittance inverter realisation in filter design

I read some theory about lowpass prototype filters in the "Handbook of Filter Synthesis" by Zverev and in "Microwave Filters for Communication Systems". I read these two because I want to understand ...
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3answers
54 views

Determining cut offs frequencies of band-pass filter

I have an RC network as follows: simulate this circuit – Schematic created using CircuitLab As far as I can tell, this has the transfer characteristic: $$ \begin{align} \frac{V_{out}}{...
0
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1answer
140 views

What are the purpose of those resistors and capacitors network before the mic jack?

I was looking at M851 motherboard schematic to learn something from these documents and saw an interesting circuit for microphone. look: 1- What are the purpose of those resistors and capacitors ...
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0answers
11 views

Converting IMU (MPU6050) raw data for a single axis and gyro init

I am looking to use the MPU6050 on a self balancing bicycle. I am using a PIC micro as the interfacing MCU. I am only interested in the angle in one axis (I'm only interested in roll). I have some ...
0
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1answer
71 views

Input impedance from RC filter to inverting and non inverting op amp

I am building a preamp for a sinusoidal current source. I have a two stage amplification process, with a bandpass RC filter in the middle. The second stage amplification is has two outputs from an ...
2
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1answer
60 views

Is it useful to think of SMPS input capacitance as part of an LC filter?

I'm at the stage of learning about switched-mode power supplies that I'm focused on understanding the role of input capacitance. Just for background, I'm working with a buck topology for this ...
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3answers
28 views

How does the ELPF and XTAL inputs on the ADV7180 recommended circuit work?

I am looking at the recommended circuit for the ADV7180 by Analog Devices and trying to understand some of the reasoning behind the design choices. I realize some of these questions may be a lack of ...
2
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3answers
79 views

What do these two omega's say about this filter?

I've got the filter that's given in the picture below, they calculate the pole and the zero of the transfer function but what do these two values for omega say, is it kind of a cut-off frequency? (...
1
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1answer
45 views

What functions do EMC filters in variable frequency drives serve?

Most VFDs I've seen have EMC filters in them, though in many cases they're optional or can be disabled by the user. Exactly what function do these filters perform? What problem are they intended to ...
0
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1answer
63 views

Designing Butterworth Filter [closed]

I want to design butterworth filter in matlab only based on order of the filter and the cutoff frequency in Hz. the syntax is for returning the ABCD matrix of statespace is ...
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1answer
52 views

How to modify this tank circuit to obtain a 3rd order passive band pass filter?

I am very confused about band pass- and band rejectfilters. I have this circuit which represents a bandpass filter. A 2nd order (2 energy exchanging elements) bandpass filter if I am not mistaking: ...
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3answers
164 views

Why filter through hardware?

I am trying to measure a signal with a voltage amplitude between 10-100 microvolts and a frequency between 7-30Hz. The guide I am following suggests filtering out 60Hz noise using a notch filter, as ...
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1answer
47 views

Notch filter ECG

I am using the Sparkfun Development kit based on AD8232 for acquiring the ECG signal from the body. Sparkfun Kit. Now I am getting a perfect ECG signal when I turn off all the power in the house and ...
0
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2answers
56 views

How good should the regulated AC/DC power supply filter be in tube headphone amp?

I am building a tube headphone amplifier. I built a AC/DC regulated power supply (220v AC to ~250v DC) but I am not sure about how good is the filter. The filter contains 120uF and 68UF capacitors, in ...
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2answers
40 views

What is the meaning of |H(jw)| concerning the transfer function

Noob question here but my books talks about the magnitude of the transfer function |H(jw)| a lot but I don't understand the meaning of |H(jw)| itself. Because of this I can't interpret the meaning of ...
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4answers
99 views

How/Why Do Bode Plots Work?

So when you derive the Bode Plot from the transfer function you plug jw into the transfer function H(s). You then get the magnitude of H(jw) and plot it to get the Bode Plot. My question is why does ...
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1answer
44 views

Active highpass filter design?

How can I design an active highpass filter with |T(0)|=0.1 and |T(inf)|=1 and one critical frequency (either a pole or a zero) at 200 Hz?
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1answer
69 views

Low pass filter output

I have a weird but annoying problem. I have an inverting low pass filter as in the figure below: simulate this circuit – Schematic created using CircuitLab I want this circuit to act as ...
0
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2answers
51 views

Why is the capacitor voltage Vin*D?

I'm trying to understand turning a pwm signal to a analog signal. From what I saw online I found that using a lowpass filter, the capacitor voltage is Vin*DutyCycle. This was given as a fact and I ...
0
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2answers
63 views

How can we calculate the transfer function from this filter?

I'm trying to calculate the transfer function of this high pass filter : So basically I'm trying to find how I can find \$V_{\text{out}}\$. Due to the amplifier we know that $$V_{in} = V_{\text{...
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2answers
61 views

Do narrow-band single-chip bandpass filters for audio frequencies exist?

I am looking for a single-chip implementation of a bandpass filter for audio frequencies, but unsure if they even exist. All the filters I've seen seem to be at least in hundred KHz range. So my ...
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2answers
32 views

Optimization of component values in LPF

I'm designing a 2nd order low-pass Butterworth filter using a Sallen-Key topology (for reminder) : simulate this circuit – Schematic created using CircuitLab Now, I am trying to find the ...
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2answers
125 views

LC circuit in radio receiver

Why is it required in radio receiver to tune the LC circuit to the the resonant frequency of the station in order to receive the station ? How this tuning filters the desired signal from the other ...
2
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4answers
90 views

Advantages of filtering signals using analog or digital methods?

In my understanding, it seems that there are, broadly speaking, two primary ways in which signals are filtered for analysis by computers, which are software-side filters and hardware-side filters (...
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2answers
40 views

What is the Kuroda method for transmission lines and why is it usefull? [closed]

I recentrly heard about the Kuroda method (when speaking about transmission lines) but didn't understand what it really is and why it might be usefull. Could someone give a brief explanation? why ...
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1answer
55 views

discrete high order filter (passive?) [closed]

Well, not completely passive. But not what's usually meant when one uses the words 'active filter'. It's going to be a filter that consists only of discrete transistors, capacitors and resistors. ...
9
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3answers
845 views

Are there any quick way to tell if a filter is high-pass, low-pass, or band-pass, just by looking at the transfer function in the s domain?

How can I quicly determine if a given filter's transfer function like: \$ H(s)=\frac{k}{s^2+ks} \$, or \$H(s)=\frac{1}{s+k}\$, is either a low-pass, high-pass, or band-pass ?
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93 views

Decoupling Capacitor (High Frequency Spike)

Wondering if anyone could help me rectify my understanding of decoupling capacitors and their role in suppressing high frequency voltage spikes (particularly increases in supply voltage). Similar ...
0
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3answers
85 views

Why are ratios relevant, but not the increments when defining center frequency of a band-pass filter?

First of all, here is my directly related previous question: Why is center frequency of a bandpass filter is given by the geometric average of the two cutoff frequencies? Olin Lathrop explained very ...
1
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2answers
43 views

high frequency noise from multiple feedback op amp

I've built a multiple-feedback low-pass filter with a TL084IN op amp. I've simulated the filter for the chosen R and C values using LTSpice and it looks like I was expecting: . I've also assembled ...
1
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1answer
30 views

Can I use barrier rectifier as a diode in bulk converter circuit?

I have this LC circuit which will work under 12V and quite high load (10-20A): The diode D1 must be a shottky diode but the only similar thing I have at the moment is actually 3-leg MBR3045CT ...
2
votes
3answers
519 views

Using LC filter instead of RC filter in mains powered circuits

Above is a dimmer circuit. In some of these circuits I see a toroid inductor together with a capacitor forming a low pass LC filter which is called choke filter. My questions are: Why is RL used ...
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1answer
48 views

Are the terms corner frequency,cutoff frequency and break frequency the same?

I am studying electronics engineering and I came across these terms..how are these terms different from each other?
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4answers
50 views

Remote Controlled Vehicle Design

For our term project we have to design a vehicle which has to have three functions; move forward, turn left and turn right. The vehicle will have two dc motors that will work at the same speed for ...
0
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1answer
69 views

Avoiding electrolytic capacitors in high-pass filters with sub-Hz cut-off

We need to design a HPF filter to AC couple a bipolar signal to a high gain amplifier. Any substantial DC left would saturate the amplifier, and thus it must be removed with the high-pass filter(HPF)....
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0answers
31 views

Active damping for Application in High Power with LC-filter

I am working on a circuit which consists of inverter subsequent by a filter as shown in the figure, the filter consists of LC and RC as branch for the filter. I have gotten after the filter a ...
0
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1answer
49 views

RC filter with an square wave input (checking my math and find my error, if it is somewhere) [duplicate]

I've this RC filter circuit (r is connect to earth on the bottom): My Vin is a square wave: With Laplace transform I derived that: $$Vout(s)=\frac{r}{r+\frac{1}{cs}}\cdot Vin(s)$$ and this ...