Normally related to EMI (see [tag:emc])

learn more… | top users | synonyms

0
votes
0answers
55 views

How to shield a USB device from high EMI

What is the best way to keep a USB device from disconnecting when exposed to a high EMI environment, such as when connected to a high voltage power supply under test? For example, in debugging a ...
0
votes
0answers
66 views

If my WIFI chip has poor performance at 5GHZ, what does that mean to the end user?

I'm testing my WIFI chip, and it has poor performance at 5GHZ. The transmit power I'm measuring is really low. How does this problem manifest to an end user? Will the internet connection be really ...
4
votes
0answers
108 views

Instrumented landing: why switching *everything* off [migrated]

Few days ago I took a flight to go back to my town. Towards the end of the journey, the captain demanded us to shut down any electronic device that we had on board, including iPods, CD players, phones ...
5
votes
4answers
747 views

Wireless Home Automation 2.4GHz versus 433MHz [closed]

Project specifications To make some things clear first(wow that sounds so arrogant): This is an Arduino project This is supposed to be internationally applicable I have experience with 433 MHz ...
-2
votes
1answer
37 views

Bluetooth Interference with High Pitched Tone

i'm building a portable stereo system and am having some unwanted noise from the bluetooth receiver. the noise is typically a high pitched tone. please see the attachment for my chicken scratch ...
0
votes
0answers
27 views

Suppressing interference in a pressure sensor circuit

I just looked over a circuit designed by my predecessor, which is used to interface with a pressure sensor. It works, but I have some doubts about the way the input filtering is done. The simplified ...
1
vote
1answer
49 views

pH sensor project: trouble with RF interference

I built this pH sensor project on a breadboard and I'm having a big problem. The output on the voltmeter is completely erratic, and I'm pretty sure it's due to RF interference. When I connect the ...
0
votes
0answers
39 views

How to debug and resolve an antenna interference problem?

We have had a board made that features an interacting processor, chip antenna and GPRS/3G module. We have proved the functionality of the board - it works - but the board is not stable. We have ...
2
votes
1answer
48 views

Atmel and coil close on a board - is interference an issue?

I'm going to build a circuit which uses AVR uC (probably ATmega8 or some ATtiny) and a coil with iron powder ring core. The coil has 330uH and will be working under current of approx. 6A. I'd like to ...
0
votes
0answers
57 views

Isolation between GSM and GPS antenna

We are doing a prototype for a gps based tracker. We got a problem in placing the GSM and GPS antenna. Both the GSM and GPS antenna are omni-directional antennas. In forums and application notes, the ...
0
votes
1answer
149 views

Microcontroller freezes (or doesn't) when plugged into different outlets in my home

I have an ARM development board (Marvell ARMADA XP CPU) and depending on which plug outlet I plug the system into, the system will freeze up after a few minutes or not. I found that plug outlets in ...
3
votes
1answer
236 views

Multiple nrf24l01, shared power, ripple/interference, DSO screenshot provided

I've got this circuit with 3x atmega328 & nrf24l01+ running off shared power supply, either 2x AA battery or 3v3 reg. It acts as a repeater, and depending on the origin of the message and the ...
1
vote
1answer
39 views

Reduce Interference in Wireless Mesh Network

I am playing with the idea of mesh network path finding. The goal is that each node can find the most efficient path through other node to a hub. One way I could approach it is by flooding the ...
0
votes
1answer
58 views

How do I place a long wire to make the EMI and inductance minimum?

I'm going to measure high current. After seeing that there is not a lot of low valued sensor resistors in the market and the available ones are very expensive, I decided to make my own current sensing ...
0
votes
0answers
46 views

How much electromagnetic interference/pollution is produced by home power-line network adapters?

How much electromagnetic interference/pollution is produced by home power-line network adapters? How do they compare for example to WiFi routers? They operate on high frequencies to achieve high ...
2
votes
2answers
64 views

Trying to Understand Spurious Sideband Interference (and some causality problems…)

Suppose I have a radio and I intend to transmit a 0.1 µs pulse on a 100 MHz carrier. Fourier theory tells me that this signal will produce some sideband interference resembling a Sinc function. ...
1
vote
1answer
91 views

NFC tag interfere with hearing aid device

I want to add NFC tag to hearing aid device for a child to monitor on smartphone (or smatwatch - either carried by children) if the tag is in the range - if not it means that child lost it and I can ...
3
votes
3answers
448 views

50MHz SPI PCB routing, use vias or resistors?

I am trying to route the SPI between MCU and ADC. However, the pin orders between MCU and ADC are not matched, there are crossings. A four-layer board is used.(signal - ground - power - signal) I ...
3
votes
4answers
562 views

How to prevent PA system from interference of 4G signal

I apologize if this is not the right place to post this. I am working on a small PA system for a weekly gathering. It catches the signal from wireless mics and output it to the speakers. I am pretty ...
0
votes
2answers
315 views

Stepper motor failing. Electrical interference?

Update: This question is already so long, I'm hesitant to add to it but it occurs to me to ask if electrical interference between the stepper motor wires could cause this sort of behavior (motor ...
3
votes
1answer
73 views

Audio oscillator cross-talk on small synth project

I am making a small 9V battery powered synthesizer with a square wave oscillator built around a 40106b Schmitt trigger (reference: http://richdecibels.com/blog/?p=11) and a few other components, one ...
4
votes
1answer
1k views

Permanent magnets near wifi device

Background I have a small circuit that consists of a microcontroller operating on 14Mhz and a wifi module. This circuit is enclosed in a small plastic box. I am considering gluing a few magnets on ...
2
votes
2answers
155 views

Verifying design that uses guard ring

I had a colleague design a board for pH sensor amplification based on schematic (fig 1)and spec in a paper. The paper recommends using the spec noted in figure 3. It uses a guard ring to reduce ...
6
votes
3answers
186 views

What Regulatory Requirements are Really Necessary for Sale in the USA?

I understand that unless you fall into some specific product categories that are exempt from FCC regulations, electronic products sold in the US are legally required to meet FCC EMC limits. However, ...
16
votes
4answers
2k views

How come radio signals don't interfere with each other all the time?

I'm a newbie on wireless technologies and I'm trying to understand how they work. One thing I don't understand is this: How come transmissions from different devices don't interfere with each other ...
3
votes
1answer
310 views

Why do library book detectors make my headphones buzz?

Whenever I enter or exit a library while wearing headphones (cheaper intra-aural type), I hear loud buzzing as I pass through the book detector gate. I can vaguely speculate at a high level that ...
1
vote
1answer
74 views

Can mobile cell stations cause interference in audio circuits near them?

It's a fact that if you put a GSM cell phone near a desktop PC and call it, the phone will interfere with the audio card and cause that noise most of us have heard somewhere. But is it the case with ...
3
votes
3answers
139 views

Are Wi-Fi 'transparent' buildings superior to antennas mounted on the exterior?

Looking in particular at wireless mesh networks in cities - is it advantageous to design a building that does not interfere with Wi-Fi (e.g. out of wood instead of steel and concrete), or would ...
9
votes
1answer
582 views

PCB clearance/keepout area surrounding wireless antenna

Suppose a PCB antenna or chip antenna is integrated onto a board design with a wireless IC, e.g. a Zigbee or Bluetooth module. What are some guidelines regarding clearance/keepout area on the PCB ...
1
vote
2answers
99 views

Radio or TV signal interference

I am curious to know why can not signals of different tv stations mix together while transmitting. I have seen many towers built near each other in mountain areas in my country. If two different ...
0
votes
1answer
146 views

Inductive phone charger mod - doesn't work with battery too close?

I am experiencing a strange issue, likely because I do not fully understand the technology I am trying to make play nice together, but maybe someone here can shed some light on it. I have an HTC Evo ...
2
votes
1answer
147 views

Possible wifi interference with processor

I am building a device that consists of an ordinary WiFi router (WDR4300) as shown here: Which works as a client and scans for networks OK when alone. The problems appear when I add another board ...
0
votes
0answers
159 views

Prevent interference caused by fan

I have several strips of addressable (LPD8806) LEDs hooked up to an Arduino. simulate this circuit – Schematic created using CircuitLab I have noticed that whenever I turn off a fan ...
0
votes
0answers
40 views

Will this RAM bypass interfere with linux's total memory count? [duplicate]

As the patent in this question shows, it may be possible to hijack a computer by bypassing the memory controller. If it's true that it only hijacks part of the RAM at a time, does that mean that it ...
0
votes
1answer
83 views

Should I use Magnet Wire as a conductor in this experiment?

I need to run a few wires from a HMC5883L compass sensor to a micro-controller to process the data. Can I use magnet wire to carry the signals from the sensor to the micro-controller or would the ...
16
votes
5answers
1k views

Why does a simple conductor start to emit EM waves when carrying a signal?

I understand that on circuit board traces with a clock, if the higher harmonics have sufficient power, it results in electromagnetic waves being emitted from the traces which creates EMI. What I don't ...
0
votes
1answer
165 views

Could an aluminum housing and passive cooling interfere with SoC's functioning?

I took the board out of a broken tablet. The SoC on the board gets hot pretty quickly. I thought about fixing the board to an aluminum plate, so that it touches the SoC and disctributes its heat, and ...
1
vote
1answer
181 views

I2C on FFC or IDE cable - interference?

This is a follow-up question on this answer. I need to communicate with I2C over approximately 10cm and I'd like to use an FFC or IDE cable for that. Earlier, I used an FFC cable to link a segment ...
1
vote
1answer
234 views

Bluetooth Interference between piconets

I am developing a device that consists of a base station and several wireless sensor nodes. In application there may be up to 30 of these devices in a laboratory with up to 5 sensor nodes ...
4
votes
2answers
441 views

Why are low frequency channels (10kHz - 200kHz) especially susceptible to interference?

I am working on a system which should communicate with a ~100kHz signal, and read that low frequency channels, e.g 10kHz to 200kHz, are especially susceptible to interference. Why is that? Are they ...
0
votes
2answers
508 views

Computer case causing interference with TV

I've recently changed my computer case to a new, bigger case. However, after I changed this case over, I can no longer watch TV due to interference with the signal. I have removed every output to my ...
12
votes
4answers
2k views

Microcontroller with a long wire for digital input

I have the doorbell button on my house wired into a GHI EMX dev board. The software evaluates the time of day and determines whether or not the doorbell should ring. Side Note: This was ...
0
votes
1answer
213 views

BBQ iginter power surge

I am building a home beer brewing rig that has several electrically actuated components controlled by an Arduino. The typical scheme is Arduino -> Shift Register -> Relay -> Component. One of the ...
1
vote
1answer
310 views

Can my weather station cause interference with my wireless network?

I know my weather station is on 433 MHz and my home Wi-Fi network is on 2.4 GHz and 5 GHz. It's ok so far and everything seems to be fine. But I found many cases on the Internet that cheap stations ...
2
votes
2answers
651 views

Would a digital compass work reliably when installed in a car?

I'm working on a project that needs dead reckoning sensors to combine to GPS readings, and is to be installed under the dashboard of a car. Currently I have an accelerometer and a gyroscope for that. ...
1
vote
1answer
620 views

How close can I place two transformers?

I need to place two of these transformers in a case. How close am I allowed to place them? Can they touch each other (of course, they will be electrically isolated)? Is their orientation with ...
-6
votes
1answer
246 views

Jamming Devices [closed]

Im am thinking about building a low power broadband jamming device to blanket a small area, around 400 sq.ft. I want my frequency range to be from DC to 100 ghz. Would amplifying the outputs of noise ...
11
votes
2answers
1k views

FCC part 15 “must accept interference from other sources”: what does this mean?

I've googled around a bit and here are the interpretations I've found in non-authoritative sources: that the device is unable to filter out interference caused by other certified equipment that if ...
0
votes
1answer
860 views

Could a bad hdmi cable be the cause of 60hz speaker hum?

I was at a friend's house trying to help him get his computer/tv/stereo connected in his new apartment. We had some difficulty getting the tv to acknowledge the video signal. The hdmi source option ...
2
votes
2answers
553 views

Ground induced noise between two connected boards

I have a CNC system that consists of a CNC controller connected to a PC via USB. The controller is in turn connected to a stepper motor driver board. My problem is that some time the turning off/on of ...