A filter modifies signals based on their frequency.

learn more… | top users | synonyms

2
votes
1answer
54 views

Light Organ — Need help with LED grid

I'm building a light organ for a school project. I've got a crossover to separate the frequencies, now I need to make an LED grid. The input will be an constantly changing analog signal (whose ...
0
votes
0answers
38 views

Demanding design on bandpass filter/ Notch filter with gain

I have posted a related question before, which can be found here: Very low noise high pass filter design However, since a different stage is to be considered, I started this new post. We are not ...
0
votes
0answers
25 views

Microstrip lines- 50 ohm line for designing filter at 3.6 GHz [duplicate]

I have a question regarding microstrip lines... why do we use 50 ohm line as a standard?? please answer and attach necessary links. Thanks
0
votes
2answers
73 views

why does passive RC filter create THD?

I am trying to make a fourth order passive RC low pass filter. I simulate it in Multisim but find that the filter creates THD. And the higher the order of the filter, the larger the THD. I can`t ...
1
vote
1answer
53 views

designing LC filter for linearizing PWM output

I have designed an h-bridge to run a TEC element. The circuit outputs output current is 4A output voltage is 4V Runs on PWM with frequency 5kHz Load resistance is 75Ω I wanted to linearize the ...
0
votes
1answer
59 views

Need comments on low noise band-pass filter design

I am a beginner in filter design. This is the bandpass filter and its central frequency is 2kHz. Would you please give me some comments on this design?
8
votes
3answers
1k views

Why too many capacitors in parallel for Vdd supply net? Can't we just add all to replace with one big capacitor?

I have given the image of Basys-2 board's power regulator IC and filters connected to it in schematic. This is just an example but this is pretty much a similar filtering design for most of the supply ...
0
votes
4answers
140 views

Very low noise high pass filter design

We are trying to design a high pass filter, which mainly goals are: very low noise. Low noise is the first concern. suppresses 1kHz by around 50dB and passes 2kHz. Gets rid of DC Dont care on other ...
1
vote
0answers
54 views

100kHz active filter design

I am designing a basic 100kHz active bandpass filter using opamps (LF353). I am only interested in receiving the 100kHz frequency (might drift a few kHz) from my input signal. I have used a basic ...
0
votes
1answer
37 views

Impulse Response of a series RC filter where the output voltage is taken across the Capacitor

I am finding it difficult to understand the steps to derive the impulse response of a series RC filter where the output voltage is taken across the capacitor, the equation to derive is: h(t)= (1/RC) ...
2
votes
2answers
99 views

Choosing between active opamp filtering or an LC filter

This question follows a previous one I asked, where I accidentally achieved undesirable results from an opamp. Since then I have read up on active opamp filters (here and here) and refreshed my ...
1
vote
1answer
50 views

DSB-SC modulation circuit

I have the following circuit which is used for DSB-SC modulation but, I can't understand Why we use High Pass Filter(I expect to be High pass filter , I'm not sure with that ) at the carrier ? Why ...
0
votes
1answer
49 views

How to filter low frequency noise on power supply from ChipCorder?

I've built a circuit using an ISD4003 ChipCorder, which is an IC for recording and playback of audio (in a telephone answering machine, for example). I've written code to send the SPI commands to ...
3
votes
2answers
113 views

RF Narrow bandpass filter (crystal ladder)

I am currently designing a narrow band pass filter at around 8Mhz, using the crystals having a resonance frequency of 8Mhz. Using the tutorial from ...
2
votes
3answers
69 views

Audio PWM DAC filtering

I have an msp430 synth project and can't decide on the output: I get an 8 bit ~45kHz PWM output out of the chip which I'd like to use as an audio signal, but I am unsure whether I can just stick ...
1
vote
1answer
71 views

How are the gain and corner frequencies calculated for this speech bandpass filter?

This speech bandpass filter circuit appears in the TI OPA344 datasheet. It says "G = 100" and passband is 300 Hz to 3 kHz. How is the gain and corner frequencies calculated from the various ...
1
vote
2answers
53 views

Optimal PWM Frequency for EMI & EMC

I am planning to design a 65W power supply which will use a PWM frequency of around 100kHz. I am specifically concerned about conducted EMI (not as much about radiated for now). I am currently ...
0
votes
1answer
45 views

How to decide to cuttoff frequecies of filter in case of using ADC( Flow: Analog-signal to ADC to bits to fir_filter to filtered_output) [closed]

FIR filter has to be used for removing the noise. I don't know the frequencies of the noise that might be adding up into the analog feedback signal I am taking. The ADC has takes just a voltage value ...
0
votes
0answers
84 views

How to scale output of FIR filter implemented in VHDL

For a DSP school project we need to implement sound effects in a SPARTAN 6 FPGA using VHDL. We tried to keep it simple and start off with a simple (100Tab) FIR filter. As coefficients we used those ...
1
vote
0answers
26 views

Powerline modem ST7580 single channel mode

I'm trying to implement a powerline module with the ST7580 modem. There is a passive and active filter design in the application note laid out which I plan to modify according to my desired carrier ...
3
votes
2answers
83 views

What is the purpose of a filter consisting of a capacitor and two inductors?

I have the following filter in a single device: It looks like a ceramic capacitor, but with 3 legs, and also states capacitance like such capacitor (only 103 printed). What is the typical purpose ...
4
votes
5answers
551 views

What is the purpose of this simple 1 capacitor 2 resistor high pass filter?

I have seen the standard high pass filter with the -3dB cutoff frequency = \$ 1/2\pi RC\$. simulate this circuit – Schematic created using CircuitLab However I have seen this particular ...
2
votes
4answers
154 views

Convert a PWM to analogue with double the voltage range?

I have a PWM output (0-5v) that I need to convert to an analogue voltage. Simple = RC filter. However, the voltage range from that analogue voltage needs to be twice that of the input voltage, and I'm ...
2
votes
4answers
118 views

Do digital Anti Aliasing filters exist for traditional ADCs?

I'm currently learning about Analogue to Digital Converters. From what I understand, aliasing occurs if the input signal being sampled has power above the "Nyquist frequency" of the ADC(Sampling ...
1
vote
1answer
43 views

Graphical Intuition for Band Pass/Stop Active Filter Responses to Square Wave Input?

In reading my text, it notes that, when a square wave of a certain frequency is applied to band pass/ band stop active op-amp filters: Band pass filters will output the fundamental frequency of the ...
1
vote
1answer
48 views

Derivation of Transfer Functions of Second Order Active Filters Resource?

We have covered the transfer functions and operation of some second order active filters (using op amps) in my electronic circuits course. However, the professor presented us with the transfer ...
1
vote
1answer
106 views

LC Low Pass Output Filters on Inverters

I've seen various schematics which feature a low-pass LC filter at the output of a inverter intended for a UPS or a Class D Amplifier. With a Class D Amplifier the load is somewhat predictable (i.e. ...
2
votes
2answers
77 views

Why use a filter?

What is wrong with just taking the Fourier transform of a signal, setting the unwanted frequency components to zero, then doing an inverse Fourier transform to get the filtered signal?
1
vote
2answers
99 views

How does this power supply (resistor/capacitor) divider filter work? [duplicate]

I've been looking at various valve guitar amplifier circuits and in specific, the power supply section. I've been seeing a particular circuit that's repeating itself here and there in the power ...
1
vote
1answer
98 views

Adding filtering to an opamp feedback loop

I am simulating a circuit based on the OPA3355 opamp using TINA-TI. Obvious warnings about simulation should be heeded but this is a TI amp in a TI program, so I'm hoping the results are largely ...
2
votes
0answers
59 views

I need to calculate the average power spectral density after passing packets through a butterworth filter using MATLAB

I am trying to generate 100 packets(row vectors each of size 8192) of random bits(1,-1),filter them using butterworth filter and then plot their average power spectral density. I have to do this ...
2
votes
2answers
103 views

Filter 5v pulse from micro input

I am monitoring an external system which sends out a 5v pulse every 2 seconds when in normal mode. When the motor is working, it sends out a constant 5v designed to power a flashing light or LEDs as a ...
0
votes
1answer
70 views

Application and uses of particular band pass filters

What are the uses of active inverting band pass filters? Also what are the uses of an infinite gain multiple feedback active band pass filter? Circuits on here: ...
1
vote
2answers
154 views

Why wont my opamp gain properly? (schematic attached)

I am trying to take a input signal which will shift between 1-5Hz and amplify only the AC portion of the signal (0.02V pk-pk, ~3 volt offset). The whole circuit has to run on 3.3v single supply DC. I ...
4
votes
1answer
124 views

Design criteria for an output LC-filter

When designing an output filter for a simple class-D amplifier I am unsure about sizing the components. Given: cut off frequency of approximately 50kHz the inductor DC resistance can be disregarded ...
5
votes
1answer
159 views

Why does this first-order RC filter with an op-amp display resonance?

I built this circuit and simulated it in CircuitLab and was trying to make an active low pass filter. However, it shows a frequency response like a resonant low pass filter and I can't figure out why. ...
-1
votes
2answers
80 views

Band-pass filter confusion

I'm having trouble understanding the concept of a Band-pass filter. Not, that I have the following signal (in the frequency domain): What I essentially need to do is remove the noise and only ...
0
votes
2answers
101 views

Simple LP filter - calculate cutoff frequency

If I am correct to calculate cutoff frequency in this LP filter I have to sum up the impedance of resistor and capacitor, right? simulate this circuit – Schematic created using CircuitLab ...
3
votes
0answers
133 views

passive high pass filter to iphone mic jack

I'm attempting to input a heart rate signal into my iPhone via the microphone jack. I need to pass the signal through a passive high-pass filter to remove the DC offset before inputting it in to the ...
2
votes
1answer
72 views

How to obtain the in-phase carrier for synchronous detection of an AM signal?

I am designing an AM receiver that has a carrier frequency of 2MHz with a bandwidth of 20kHz; i.e., the information signal has 10kHz bandwidth. What I've designed is basically like this: So I need ...
7
votes
5answers
440 views

Difference: Low Pass Filter and Large Capacitor?

When working with microcontrollers it is recommended to place filter/decoupling capacitors between a supply pin and ground. I understand the purpose of this implementation, namely that voltage across ...
0
votes
2answers
69 views

RC Filter for Low Power consumption

I was thinking about selecting R & C values for an RC filter, so that it consumes less power, in the overall circuit. Thinking about it, a larger value for R means a larger \$I^2R\$ loss. But a ...
2
votes
2answers
160 views

What is the best approach for reducing harmonic distortion?

I have a power system where on some buses, large converter driven machines result in high harmonic distortion. As far as I know, there are mainly two ways to reduce the harmonics. A filter to ...
5
votes
2answers
102 views

Hypothetical question about filters

As I understand it, the ideal frequency response for a filter is that we want maximum gain in pass band, a vertical or instant cutoff and 0 in the stop band, however this is ideal and can never be ...
3
votes
2answers
156 views

FFT + filtering sound = triggering signal

I'm trying to FFT the live input sound and filter it to have only 350 to 500 HZ. So, my goal is to turn the LED light on only when some sound has frequency between 350-500. I looked at FFT codes, but ...
2
votes
3answers
181 views

Recognizing low-pass filters

Does the capacitor in this circuit serve as a low-pass filter? The premise of the circuit is to be a small SD card based music player. The write up, Simple SD Audio Player with an 8-pin IC, says ...
-1
votes
1answer
90 views

Is it possible to buy high pass filters that work in the 100 kHz range?

I want a device that rejects 100 kHz but lets through 150 kHz. I tried building a simple passive first order circuit but the roll-off wasn't sharp enough. Most standard electronics vendors don't seem ...
0
votes
0answers
52 views

Measurement of frequency domain ripple of a filter

I am trying to analyze the passband ripple of various filter designs. I would like to know the correct way to measure the ripple. The trivial answer is to find the min and max amplitude in the ...
0
votes
0answers
71 views

Band-Pass Filter Using High-Pass and Low-Pass at PSPICE

I am trying to create fourth poles band-pass filter.I set up this filter using texas instruments programme but I supposed to do with PSPICE.I have a crucial problem.As you can see on the screenshot, I ...
0
votes
1answer
115 views

Problem with TDA2050_single_application_Circuit

I have many problems with TDA 2050. Why TDA2050 use high-pass filters? What is the bandwidth of it? Does the range of bandwidth is from the range of frequencies below the human hearing?(20-20KHz) I ...