Questions tagged [high-pass-filter]

A high-pass filter is an electronic filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency.

Filter by
Sorted by
Tagged with
0
votes
3answers
108 views

Is this a high-pass filter?

I am not very sure about how to completely solve this question. I tried to calculate the equivalent impedance by C and R and got R/(1+jwRC). Then I calculated the transmittance by using the voltage ...
-1
votes
3answers
50 views

Single capacitor for Powerline communication - AC coupling

First of all: I am not talking about traditional powerline communication (ethernet protocol etc) but about a very simple and primitive communication, like serial data transmission (https://en....
0
votes
1answer
45 views

Are there advantageous situations when we cascade filters by descending Q-factor instead of ascending?

We usually cascade filters in ascending Q-factor to avoid saturation in each individual stage. But are there advantageous situations when we cascade filters by descending Q-factor?
0
votes
0answers
18 views

Use a Passive High Pass filter to filter out voltages from piezocrystal under a certain threshold

I have a piezo crystal (SEN-10293, datasheet: 7BB-20-6L0) that I am using to detect if a person sits on a chair. The compression of the crystal generates enough voltage to wake up a microcontroller ...
0
votes
0answers
42 views

Output AC coupling: upper limit or lower limit?

I bought a DC2900A board for my project. In its datasheet it is stated: The maximum repetition rate of the pulsed laser should be 100kHz. The DC2900A repetition rate is limited by the output AC ...
3
votes
2answers
793 views

Why is the output of a high-pass filter not 0 when the input is 0?

I'm trying to design a 5th order Butterworth high-pass filter built on the Sallen-key topology with a cut-off frequency at 100Hz. For some reason, the output has a DC offset of around 5mV when the ...
0
votes
2answers
56 views

What is the behavior of electrons in a highpass filter circuit and what is an equivalent closed loop circuit?

I am being explained that an highpass filter in a circuit looks like this: It is hard for me to understand how this circuit works. Vin is AC voltage. I'm wondering what is an equivalent closed loop ...
0
votes
0answers
65 views

LPF 12dB/octave design

I'm designing a diode limiter for audio use where the signal is high passed through a discrete transistor circuit. After the diode stage the signal would need its low end restored and I'm struggling ...
1
vote
1answer
50 views

Treble bleed frequency cutoff

I built an attenuator for my guitar amplifier. I took the circuit from here but left out the 4 ohm toggle since my amplifiers all have 8 ohm outputs. Below is a simplified schematic of the circuit (...
0
votes
0answers
30 views

Transformation from Normalized Low-Pass Filter to Denormalized High-Pass Filter

I would like to ask a question about the a method (method number 2) to go from a normalized LPF to a HPF: Note: normalized refers to frequency normalization for the mentioned filters. 1- One method ...
0
votes
1answer
73 views

Active highpass filter for microphone, how to choose cutoff frequency?

I am currently taking a class on filter design, and I am learning by doing. I want to make a small project by building a microphone circuit. I found online a tutorial by Great Scott. He made a circuit ...
1
vote
2answers
426 views

Approximating the dirac delta function on LTspice to find the impulse response of a high pass filter

I have an assignment which requires me to find the impulse response of a high pass filter on LTspice. In order to do this the question suggest feeding a Dirac delta function as an input to a simple ...
0
votes
1answer
77 views

Having trouble with an aviation-band receiver

I finished assembling an aviation band receiver that I bought online. I thought it would be good project for my resume, as I am an electrical engineer major at a University in California. I read the ...
0
votes
1answer
55 views

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 ...
0
votes
1answer
49 views

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 ...
0
votes
1answer
35 views

Interpreting triangles in RC high pass filter circuit diagram

I came across the following image of a RC high-pass filter There is also an initial analysis that says that there is an initial condition for the output voltage that says $$v_O(0^-) = 0$$ which ...
0
votes
1answer
58 views

Help finding multiple feedback (MFB) high-pass filter design formulas?

I can't seem to find some easily code-able formulas for MFB high pass filter. I have found plenty for the low pass filter, but absolutely none for the high pass filter. For example, the formulas on ...
2
votes
3answers
904 views

Conundrum: High pass filter passes DC?

Consider a simple C-R 1-pole high pass filter. Apply a step input. The rising edge of the output rises up and then exponentially decays back to zero. Integrating the output over all times yields a ...
2
votes
1answer
46 views

Transistor Amplifier Signal Drops Off Below 200-300Hz

I tried to build a dual transistor amplifier from a schematic I saw, and used AC Analysis in LT Spice. What I found was that the current and voltage at my simulated 8 ohm speaker load was dropping off ...
0
votes
1answer
86 views

How to find a amplifier that named “ISP” on a circuit?

I am analyze the circuit. I can't find any relation about the name ISP of a op-amp. When we look the high pass filter we see there "ISP" name. I search it on google but I can't find nothing ...
0
votes
1answer
46 views

best high pass filter topology to extract low V kHz range pulse from noisy 60Hz line voltage before daq

I need to extract a 1 kHz-10kHz range voltage pulse created by a current pulse I inject on an harmonic rich 60 Hz network and that propagates on it. The line voltage is 120V AC. harmonics 2 and 3 are ...
2
votes
2answers
81 views

Detecting small AC current signal generated by phototransistor

I'm trying to detect a small AC signal (~10kHz) generated by a phototransistor on a magnitude of 10nA~1uA using the following circuit by converting the signal to voltage signal first and then filter ...
0
votes
0answers
50 views

Question about filter transformation

I'm studying filters. In particular, I'm studying low-pass to high-pass filter transformation. I know that you only need to design an equivalent normalized low-pass filter and then, by using a ...
0
votes
2answers
44 views

How to apply high gain to filtered signal without shifting voltage level?

I have an op amp gain circuit at the output of a 2 stage filter. It seems like at high gain settings (x500), the steady state voltage shifts significantly. I am trying to keep it at ~1.7V and it ...
0
votes
1answer
36 views

TPA0253: Help Understanding Mono Output

I'm working on implementing an audio amplifier into a circuit design, and I am trying to understand the output configuration for the speaker using the TPA0253. I will be using a 8 ohm, 1W speaker for ...
2
votes
2answers
174 views

Band-pass filter vs. Serial Low-pass+High-pass filter - Is there a difference?

Is there a difference between a band-pass filter (BPF) and tying a low-pass filter's (LPF) output to the input of a high-pass filter (HPF)? It seems to me that they should do the same thing---or ...
1
vote
0answers
36 views

High pass filter that locks voltage at certain amount until frequency is reached

I have a sine wave that is biased at about 1.5V DC. I want to create a high pass filter that allows any frequency through greater than 4000Hz. Want I want my high pass filter to do is to be at 1.5V ...
0
votes
1answer
46 views

What change should I make in my Lead Compensator circuit below to reduce the DC response? Vin be sine wave with variable frequency

I want to increase my cutoff frequency, Fc. As Fc=1/2piR*C, Should I reduce the value of either resistor or capacitor to increase my cutoff frequency?
0
votes
1answer
79 views

Why does this high pass filter behaves like band-pass filter on Multisim AC Sweep simulations?

I have this high-pass filter schematic and its AC Sweep simulation. Until the break through the end, the graph is right but I can't see why the graph breaks on the right hand side and filter behaves ...
0
votes
1answer
22 views

Shared via on 22pF cap only used to smooth differential clock signal?

Google's so cluttered these days, it's hard to find simple answers. I've got differential clocks running around 500MHz (1000Ms). There's some optional 22pf caps on each Address line, going to the ...
2
votes
3answers
108 views

Finding transfer function and tuning cutoff frequency of High-Pass FIlter

I have a schematic for a High-Pass filter that has a cut-off of around 7Hz. I obtained the designed online and want to tune it to have a cutoff of 5Hz instead. I assumed I would proceed in the ...
4
votes
2answers
365 views

High pass filter - Cut-off frequency calculation doesn't match simulation

I have made the following simulation with the circuit you can see below: I'm asked to find the cut-off frequency for this filter. From the simulation, it looks like it \$f_c = 500 \text{Hz}\$ or ...
0
votes
1answer
57 views

Dielectric absorption in capacitor (audio crossover)

I want to understand the selection of a proper capacitor type for a simple audio crossover (passive lowpass filter before woofer, passive highpass filter before the tweeter). Various blogs more or ...
0
votes
2answers
67 views

Analysis of a high-pass filter

I'm doing some analysis of op-amp circuitry including the high-pass filter shown below. I was given three questions to try further my understanding on the analysis of such system. However, I am ...
0
votes
1answer
84 views

How to derive the gain (ratio of output voltage to input voltage)

$$ \frac{V_c}{V_s} = \frac{\frac{j}{\omega\cdot C}}{R+\frac{j}{\omega \cdot C}} $$ Given this starting formula, how to rationalize the denominator and find the gain?
0
votes
2answers
102 views

How is dc restorer circuit used for PWM demodulation/detection?

In the Microelectronics Circuits textbook by Sedra & Smith, it is said that: As an application, consider a pulse signal being transmitted through a capacitively coupled or ac-coupled system. ...
0
votes
1answer
134 views

How to calculate cutoff frequency for a high pass filter in DC biasing circuit

I would like to DC bias an AC signal using a voltage divider as shown in the following schematic. I realise the bias point would be subject to noise from the power rails, but that is not a concern for ...
0
votes
1answer
199 views

how to design a low pass filter for square waveform

I have square wave signal of 100KHz with few high frequency ringing from 555 timer.when i tried to use a 100KHz first order rc low pass filter,i got a sawtooth waveform because the 100KHz square will ...
0
votes
1answer
1k views

How to remove DC offset (and make average DC value 0V) from ADS1261 square wave AC-excitation circuit

I am attempting to remove the DC offset from the 1 kHz, ± 2.5 V, AC square wave output pins of an ADS1261 (http://www.ti.com/lit/ds/symlink/ads1261.pdf). However, when measured on the oscilloscope (...
0
votes
1answer
45 views

PMOS unexpectedly passing current with capacitor on drain

I am designing a circuit to get a pulse when a switch opens. When the voltage source V1 is connected, the switch SW1 starts closed. I want Vout to briefly go high when SW1 opens. The circuit I ...
0
votes
2answers
805 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
1answer
88 views

Synthesizing this simple analog notch filter?

I want to synthesize this simple analog audio filter which is a notch: The inductor with resistor creates a simple one-pole low pass filter with the cutoff frequency at: fc = 1/(2pi L R) The ...
0
votes
2answers
77 views

Audio HPF cutoff frequency selection

I need to use a HPF for my headphone amp and I want some suggestions about at what frequency I should place the cutoff frequency. Currently I want to use a HPF with a fc=15~20Hz but this gives me -...
0
votes
1answer
62 views

What condition must be verified by the frequency so that an RC circuit acts as a differentiator? [closed]

So I am theoretically planning to make an RC differentiator circuit but I'm still a rookie with it so if someone can help me it would be appreciated.
0
votes
2answers
17 views

Should Passive LPF/HPF Component Selection Depend on Ability of Input to Source Current?

When choosing R and C for a passive LPF or HPF, should you take into account the input's ability to source current? I'm currently working on a passive HPF for an input that can supply up to 10 mA @ 3....
1
vote
2answers
98 views

\$V_o/V_s\$ of given circuit

I'm trying to calculate $$\frac{V_o}{V_s}$$ of the given circuit, but don't really know what to do with the voltage dependent voltage source. As I'm not an engineering student, this stuff is very ...
3
votes
1answer
145 views

Need help in designing a BJT Amplifier with Avnl = 100

For our final project, we need to design a "single-stage BJT-based highpass amplifier using voltage divider configuration". The amplifier has the following requirements: \$V_{CC} = 12V, f_L =...
0
votes
1answer
109 views

RC filter for emitter follower input

Please could someone explain how to compute the impedance with which to determine the frequency characteristics of the high-pass input filter in the following circuit? My question is prompted by an ...
1
vote
1answer
618 views

Questions about the baxandall circuit

So I understand that the baxandall circuit is a tone control circuit, able to configure a bass and treble through RC filters. The general understanding I have from it, is that the capacitance of the ...
0
votes
0answers
73 views

How does a high pass filter and a low pass filter work for an amp?

I'm researching how to incorporate treble and bass into an amp. X1 is for bass, X2 is for treble and X3 is for volume. Intuitively, for me, if a high pass filter only allows frequency above a ...