Questions tagged [attenuator]

An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform.

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126 views

Attenuator Input Voltage Problem

simulate this circuit – Schematic created using CircuitLab I'm trying to use an attenuator with a PIC32 microcontroller. Basic idea is that; 1) I enter attenuation value through computer 2) ...
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2answers
966 views

Soft fade out circuit for turning off speakers

I have some loud speakers connected to an amplifier. The problem is when I turn the preamp off, it sends a loud POP noise through the speakers. The turn off of the amp is delayed by 1 or 2 seconds, ...
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Is there a difference between voltage divider and attenuator?

I am thinking about using a voltage divider to scale down the signal by 2/3 (-1.76 dB) as the following circuit diagram: When I googled with a keyword attenuator, I got a list of attenuators such as:...
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1answer
89 views

50 ohm Dummy Load With 50dB Attenuator

I am designing a 50 ohm 10 watts dummy load for 100-1000MHz frequency range. The signal strength should not exceed -10dBm. The load must be able to dissipate 5 watts minimum, that is +37dBm. The ...
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Why is an attenuator placed on the scope end and not the PCB end?

I've noticed when adding an external attenuator between PCB and the scope (1MOhm) that it is placed in this manner: PCB -> SMA Socket -> SMA Cable Plug -> SMA Attenuator -> SMA-to-BNC -> Scope Why ...
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89 views

Attenuating mid-supply biased audio signal before AC coupled audio amplifier

The context here is simple volume control of a DAC generated audio signal with a potentiometer before an audio amplifier stage in a single supply, battery powered system. Is there any advantage to ...
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3answers
415 views

Power Ratings of RF Attenuators In Series

If I connect RF attenuators in series, does the power rating of the attenuator closest to the antenna have to be high enough to handle the expected RF power on its own? Or does the placing attenuators ...
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21 views

Error in simulation results for balanced pi type attenuator

I wish to design a balanced pi type attenuator to give attenuation of 20dB and characteristic resistance of 500 ohms. I have found out the necessary resistances required to design the attenuator. ...
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1answer
44 views

Speaker to line level circuit and values needed please

First post, so please go gentle. I am simply looking to take a digital, mono amplified speaker signal (3w @4 ohms at 5v) and feed a Bluetooth transmitter, so I need to make sure I don't mismatch ...
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2answers
62 views

Noise figure of an attenuator is equal to the loss

Does anyone know a mathematical proof of this concept? Are there limitations of some kind or is this a general statement for all passive elements? Thanks in advance.
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2k views

Is there a 10X probe compensator BNC, but with out the probe?

Is there such thing as a compensation BNC like the ones found on 10X probes? I'm basically taking about a BNC coupler with a resistor and a adjustable cap in it. I guess it would be like a standard ...
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34 views

Attenuators in Waveguides

Let's consider for instance a rectangular waveguide with TE01 mode. As shown here, a possible attenuator may be realized with a metal card placed so that it is tangential to the electric field. Here ...
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38 views

Impedance Matching required at Output of RF sampling DAC?

I am designing a schematic with TI DAC38RF80. This DAC is having integrated balun and gives single ended output voltage upto frequencies 4.5GHz. Output power of this DAC is less as shown below: In ...
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2answers
783 views

Compensated Attenuator question

In the explanation, it explains that C2, C3, C4 are for frequency compensating the impedance of C1 which varies according to frequency. Can someone explain how C2~C4 does it? and why the designer ...
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1answer
73 views

Design of attenuators in microwave systems

A thin dielectric strip is coated with a resistive film to attenuate microwave signals. However, the dielectric strip is tapered at both ends to reduce reflections. Why does the dielectric strip even ...
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1answer
598 views

61000-4-6 CDN calibration - how to factor in the 6 dB attenuator?

I am seeking some clarification around CDN calibration for 61000-4-6 (RF conducted immunity test). By following the standard and some application notes, I am pretty sure I have it sorted. I just ...
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1answer
85 views

Lpad wiring, is gnd needed?

I'm building an attenuator using an Lpad. Do I need to connect '1' to GND? What difference will it make? Here's my circuit (Fritzing didn't have mono-jack connectors or an Lpad, so I'm using the ones ...
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133 views

How can I attenuate a video signal in discrete steps using digital control? [closed]

I would like to use a μController to adjust the brightness of VGA/EGA RGB signal. My intention is to allow for a setting from "full brightness" (0% attenuation) to "completely dark/black" (whatever ...
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5k views

Why do 0 dB attenuators exist?

I am reading this paper : Upgrade of a low-temperature scanning tunneling microscope for electron-spin resonance and found that for thermalization, they use 0 dB attenuators. Page 6: Having the ...
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1answer
114 views

Active analog attenuation with OPA2340

I wish to have active analog attenuation circuit. Following this page, I got myself some OPA2340. I use the B-side to keep the numbering somewhat intact. I go with the design on Figure 16-2 (p. 14/...
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2answers
227 views

RF Attenuator Failure

I am attenuating an audio frequency (50 KHz) signal that is pulsed at 666 W for 300us with a period of 300ms. I estimated the power dissipated averaged over a period to be approximately: \$\frac{300 \...
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1answer
121 views

DB25 to TTL logic (voltage control) [closed]

I am trying to control a 6-bit digital step attenuator for a project, with an Arduino (here, Arduino Due or Arduino Mega). The given attenuator has a software to control it. So, I connected the ...
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2answers
900 views

Adding audio-in port to plasma ball with built-in Microphone

I have a Plasma Ball with a built in microphone and would like to add another switch S1 and an audio-in port to the circuit J1. How do I calculate the line attenuation R1 and R2 resistors? My idea ...
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1answer
84 views

Energies of the fields in a plane wave, attenuated and unattenuated

This is a combination of two of my previous questions (question 1 and question 2) which are related. I'm trying to learn both how energy is carried in the electric and magnetic components of a plane ...
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1answer
89 views

What are the mechanism and effects of non-linearity in an attenuating barrier in the presence of a high-strength EM field?

It's my understanding that in electromagnetics, if an attenuating device is functioning linearly, it means that 1) input and output signal strengths are proportional; and 2) input f = output f. How ...
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1answer
229 views

Linear and non-linear attenuator

[edit 3/2/18] There are problems with the title and wording of this question. I would edit, but to do so would alter the relationship between the question and the answer that I accepted. So, I have re-...
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61 views

Strong H fields: electronic items susceptible to thier damaging effects and how to shield them

This is another question related to magnetic fields. I'm trying to determine the thickness of copper foil that would be required to shield common electronic items from H fields of about 133 A/m over ...
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3answers
78 views

The electric and magnetic components of far field EMR and shielding thereof

This is a newbie question. I'm pretty sure of the answer, but I would like confirmation. I found this thread in this forum that came close to what I was looking for, but I think my question is ...
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1answer
972 views

SNR and Attenuation Question

Hello, I have a question above from random material and tried to solve it. Here, I assume signal power to be S1(dB) and noise power to be N1(dB) at input, and S2(dB) and N2(dB) at output. So below ...
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3k views

What does the attenuation setting do in an RF spectrum analyzer?

I have to make measurements of the RF power which a circuit is delivering, and I am using an RF spectrum analyzer for that purpose. I am a beginner in this topic, so I apologize if the question is too ...
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3answers
175 views

Characterization of RF Amplifier Chain

I am using a 3 Amplifiers chain for a Receiver system. The required Output is -32dBm while the sensitivity of the system is -55 dBm, I am able to achieve this. But the maximum I/P power for the ...
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1k views

problem solving: line level to iphone attenuator buzzing sound

I'm trying to use the mic input on my iPhone to record line level audio. I have made a cable with an attenuator as shown in the picture below. Recording from my macbook pro works like a charm (3,5mm ...
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3answers
451 views

Transformer provides no attenuation for differential transients

I have read few articles about transformers and they all point to the fact that they are excellent attenuators for common mode transients, but not for differential mode transients! One of this ...
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1answer
360 views

Audio attenuator has audible pops

I'm copying the recommended circuit (the 'Higher Performance' one, actually) from the LM1971 audio attenuator datasheet but there are audible (loud) pops on the output. I'm using OPA227s for all op-...
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1answer
686 views

Adapting an HF attenuator to higher power

I want to make a 25W HF amplifier that can handle an input up to 8W. I found a schematic by ON6MU which can handle up to 2.5W input. There is an attenuator at the input that I copy here. R3-4 is 1W, ...
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2k views

Smith Chart Explanation

I'm working on designing some hopefully simple RF (912 MHz) attenuators. I need a few different levels of attenuation but each different attenuator can be fixed. I have prototyped one using just off ...
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2answers
277 views

Why are the ADC and DMM readings different?

While doing an experiment we reached a conclusion which we wrote down as the DMM and the ADC reading being different. Now after doing some research It does confuse me as a DMM does contain an ADC of ...
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1answer
645 views

Bandpass Filter Attenuation?

I'm trying to split an audio signal into 5 channels, letting 5 different ranges through each filter (low, mids, highs, etc..). What I'm finding is that each bandpass filter has different levels of ...
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2answers
1k views

How to test an RF attenuator with limited tools

I have an RF attenuator with the specification: Freq DC to 3 GHz 30dB attenuation 2W avg power rated VSWR = 1.2 max Imp = \$50\Omega\$ How can I test this attenuator without a spectrum analyzer? I ...
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1answer
96 views

generating a 10mVpp signal from computer

I have an input to a system that requires a 10mVpp max signal. I have to use my computer to input it due to constraints out of my control. I am well aware an audio card cannot go down that low. I ...
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2answers
574 views

Audio Mixer Passive Attenuator Circuit

I'm currently designing a digital audio mixer. One common thing found on audio mixers is a optional 20dB pad on the input. I've seen some attenuator circuits but all of them require you to know your ...
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1answer
859 views

Why does inserting a resistance in the common of my scope probe cause it to pick up AC noise so much worse?

I'm poking at the inside of a USB oscilloscope, with the hope of modifying it so that the scope probe commons can be referenced to different voltages. When I use my USB oscilloscope to measure a 24V ...
2
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2answers
957 views

Analog vs Digital attenuation for an ADC

I'm designing a digital parametric EQ that will go in front of a high gain guitar amplifier. I want to have the option to boost signals up to 12dB. I plan on implementing this either by attenuating ...
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1answer
151 views

In what order should I isolate and attenuate an audio signal?

I have a cheap bluetooth audio module (with no documentation) that outputs a signal greater than line-level. It was probably designed to be connected directly to small speakers, since the ground on ...
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2answers
6k views

Best topology for active attenuator

What are the advantages and drawbacks of each op-amp attenuator topology ? Which one would you use ? Resistor divider followed by a buffer : Inverting op amp attenuator :
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834 views

OpAmp: Better to actively attenuate, or drive full range into a divider?

I want to get a +-15V differential signal (60Vp-p) into an ADC that has a single 3.3V supply. When I asked a friend to proofread it, he was concerned about the noise performance of R5-R6 vs. using R1-...
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610 views

Using Op-Amp for attenuation to give input to sound card

I know there is lot of question asked about this topic before, I read them but there are some limitation on those circuits which make me ask this one. I want to do analysis of main voltages(220/50Hz)...
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1answer
973 views

RF load (terminator) at the end of RF attenuator

Do I need to install RF terminator at the end of RF attenuator? Let's say that max power output for RM port is 50W and I'm using 100W 50dB attenuator. What if I was using 50W 40dB attenuator? Is there ...
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3answers
889 views

Unbalanced pi- attenuator - Problem with simulation

I've been trying to simulate the asymmetric pi-attenuator example on this page with different source and load impedances: http://www.electronics-tutorials.ws/attenuators/pi-pad-attenuator.html I ...
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2answers
177 views

Digitally controlled smoothly variable gain?

I have a circuit that outputs about 600mVpk wave shape. I need to be able to output between 10mVpk to 10Vpk accurately, preferably with no calibration but a known error. The whole process should be ...