Questions tagged [wireless]

Using other than a wired connection to transfer signals or power. Includes optical and (ultra)sound, but most often refers to RF (radio-frequent). Distances can be as low as centimeters (e.g. RFID), there's no upper limit.

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18 views

Wireless Adapter to Bluetooth adapter

i had a Lenovo Essential Wireless Keyboard and Mouse Combo . but now i have only its wireless usb adapter that i used to insert in my pc so that my keyboard & mouse can connect through it ...
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69 views

I Need Help Making a Weird Custom Flashlight

As said in the title, I am trying to make a homemade flashlight. I have no experience when it comes to electrical engineering and I have a very basic understanding of this stuff. What I am trying to ...
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47 views

Custom products for home automation

Disclaimer: I am new to electronics and have very limited knowledge. Basically from coding background. I am looking to fix 2-3 basic home issues using some sensors and wifi, kindly suggest right ...
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1answer
22 views

SPI sensor wireless transmission using nrf24l01+ but without microcontroller

I have a tiny sensor which has SPI signal. The sensor has only two lines (other than power and ground) and it takes clcok signal from a board and sends the SPI signal back to the board. I want to take ...
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105 views

How does analog video transmission work in toy drones?

I'm trying to get a big picture understanding of how video transmission works. How is the video transmitted in FPV transmitters like here? In the specs, it says FM. So is the analog video (NTSC/PAL) ...
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33 views

Amplifier gain in budget links

How does an engineer calculate the required power/low-noise amplifier gain after she/he is provided with the link budget of the system?
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38 views

Simulate WiFi Stations for testing the AP

I was thinking if I can simulate WiFi stations(around 5 numbers) in my laptop, that I can try associating these stations to my AP and load test the AP. Could some one suggest on this or is there any ...
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2answers
115 views

Synchronization in digital communication

I am an undergraduate student and studying digital communication systems. I am not able to find any good resource where I can self-study about synchronization and it's types (time, frequency and phase ...
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2answers
42 views

MIMO system model

We consider a wireless communication system, where there is only Line Of Sight path between the MIMO transmitter and the MIMO receiver. MIMO antennas are used here to increase the directivity of the ...
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67 views

What sort of oscillator topology is used in WiFi/BT transmitters?

Thinking of cheap(er) consumer wireless products. Modulator aside, how is the RF carrier signal generated? Do they use really small capacitances/inductances on a chip die to make an RLC (say, Colpitts-...
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30 views

Unstable Phase of Channel Impulse Response

I'm using DW1000 UWB radio transceiver and extract its channel impulse response (CIR). The CIR output by the transceiver is the complex baseband CIR. In a static environment, the CIR is a LTI filter ...
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14 views

One Channel Relay Board with NRF24 / WiFi connectivity with built in power supply

I have been looking out for a board which has a one channel relay along with some wireless connectivity such as a NRF24 module or a Wemos D1 Mini attached to it aong with a built in power supply. Is ...
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26 views

Lora sx1278 implementation by Arduino Uno

I'm implementing a Lora network, with two SX1278 modules and Arduino Uno. Lora is based on three classes. A , B and C, The question is : for change For example A to B, what should exactly change in ...
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68 views

What properties differentiate specific wireless communication technologies?

Is it just the frequency range that a particular wireless communication technology operates in? (for example WiFi 2.4 Ghz band (2,400 to 2,483.5 Mhz)). Can a frequency range of one technology overlap ...
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33 views

CSMA/CA - What happens if a faulty WiFi station does not silence itself when an RTS/CTS is received?

In a WiFi network, assume a WiFi station does not silence itself for an RTS/CTS reception from other stations and it keeps on transmitting. I have few questions related to this scenario, 1.Will that ...
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42 views

Custom wave frequency for car radio [closed]

My car radio doesn't support Bluetooth and I am wondering how to solve this problem so I can play songs from my phone. The first idea that came to my mind is obviously just to buy a new radio. However,...
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61 views

Capacitance per centimeter

I need to design a 1 pF interdigital capacitor for a MMIC design, so I am using an online calculator to find out the dimensions ( https://www.rfwireless-world.com/calculators/interdigital-capacitor-...
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92 views

Figuring out transmission protocol in cheap wireless door bell

Due to boredom I've tried some reverse engineering of simple cheap wireless ring bell which uses 433.92MHz transmitter and receiver via OOK modulation. It sends several times the same information. On ...
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47 views

Time scale comparison between fast-fading and path-loss in wireless communications channels

As I know, when receiving mobile users move, the fast-fading channels between transmitter and receivers may vary very quickly as wavelengths change, e.g., every 2.5 ms. On the other hand, when we ...
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28 views

Is spatial multiplexing always required to define MIMO?

From Wikipedia: In radio, multiple-input and multiple-output, or MIMO (/ˈmaɪmoʊ, ˈmiːmoʊ/), is a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas ...
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30 views

Can i Increase the NFC range upto 50cm by making a bigger antenna? i only want to write data into a NFC enabled EEPROM?

As NFC are active upto 15cm range, i/m using a PN532 to write data into a NXP NFC enabled EEprom, which is successful, i want to increase its range by 2X by increasing the Power or size of Antenna for ...
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2answers
113 views

Reading bookshelf contents using RFID tags on books [closed]

I apologize if I make a grammar mistake... I'm a telecommunications engineering student and I have an idea for my grad project. It would be something like a SmartBookshelf. My idea is to implement a ...
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1answer
50 views

CC1101 not always working

Our project has one CC1101 transmitter sending signals to several CC1101 receivers. The transmitter sends signal to the first receiver, waits a couple of seconds before sending signal to second ...
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1answer
31 views

Are BLE attribute handles constant?

Say for example you have an embedded peripheral BLE device which has a single BLE service with some characteristics and the initialisation order is always the same (service is added, then ...
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36 views

Are there any special considerations for extending a UHF-carrying coax wire in a small device?

In the process of doing a repair on a mobile phone, I've tracked down a "no service" issue to an antenna lead inside the case. Specifically, it has detached from the U.FL/MMCX (I'm not sure ...
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1answer
79 views

How does my 802.11 a/b/g/n wireless card determine the modulation to use?

I was thinking yesterday about how the 802.11 a/b/g/n standards all use different modulation schemes, but my wireless card manages to detect frames from networks that may use any of those modulations. ...
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74 views

Is interleaving used in MIMO?

Correct me if I'm wrong, this is my understanding of MIMO: Is this how MIMO is able to increase data rate?
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86 views

How does MIMO increase data rate?

I understand how using multiple antennas helps improve reliability as it combats multipath propagation through redundancy. But how does using multiple antennas increase data rate?
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25 views

Confusion about basic reference distance based path loss formula in wireless communication

In the following, I am confused about results I am getting by the reference distance based pathloss formula. My transmitter power is 1 mW (i.e. -30 dB). But the received power is much much higher than ...
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88 views

Antenna Radiation Patterns Explained

Been struggling to find information that I find to be obviously missing on how to interpret antenna radiation patterns. For example have a look in the datasheet for my chip antenna. I can understand ...
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2k views

Why can a square wave (or digital signal) be transmitted directly through wired cable but not wireless?

Like ethernet cable, optical fiber. We have a square wave signal, do we just send that squre-wave signal directly down along the cable? If we do send it directly, why we can not send the square-wave ...
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72 views

Modifying library for the WSSFM10 Sigfox module for compatibility with STM32L476RG

Arduino IDE version 1.8.13 installed. Selected options: Board: "Nucleo-64" Board part number: "Nucleo L476RG" U(S)ART support: "Enabled (generic 'Serial')" USB support (...
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24 views

Having trouble setting up a data call via AT Commands and using the wifi chip as a hotspot

I have a WiFi chip embedded on an evaluation board which also has an application processor which runs A-grade Linux, in addition to a modem processor. I want to set it as a hotspot via hostapd which I ...
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17 views

Why use both packet detection and symbol time estimation in the receiver of WLAN(WIFI) in 802.11

n IEEE 802.11 Wlan, at the receiver side, we first use packets detection algorithm to detect the start of the packets, and then uses fine symbol timing estimation algorithm to find the start of the ...
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1answer
74 views

What connector is this? (Inside a wifi modem)

I was about to attach an antenna to my 4g modem and thus trying to identify which connector is there on my modem board and i found this connector (4 of them, 2 for 4g and 2 for wifi). I tried ...
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1answer
34 views

Wireless sensor network in practical for beginner

I am a master student, and I used to implement my protocol or scheme of WSN in the simulator(e.g., N3S or MATLAB). I am ...
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33 views

How to model MIMO channel matrix for numerical results

I am willing to include the channel matrix in my analytical model (which only includes pathloss and antenna gains). But from what I have seen, channel matrix can't be used to produce numerical results ...
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53 views

Does my Wireless Charging PCB need to have FCC, UL, CSA, certified marks?

I have a simple 5W output wireless charging device that uses a tx coil to transfer power to a phone, this is powered from a 1800mAh battery. Do I need any certifications for this?
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35 views

Open/close gate

This would seem like a problem that could be solved by buying it at a store, but it doesn’t seem to exist. I have a fenced backyard with two gates. When I let the dog out I’d like to be able to look ...
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1answer
31 views

Amplifying signal strength of a u.fl antenna

I have a mini pcie wlan card which uses a mini pcie to pcie x1 adapter card. The adapter card has 2 threaded male connectors which look exactly like conventional rg6 but smaller. Those lead directly ...
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1answer
68 views

Nearby jail's signal jammer affecting cellphone and devices using 2.4GHz band

I just rented an apartment that seemed perfect at the first sight. However, once I moved in, I noticed a lot of instability on my cellphone signal. I found that odd, so I did some research and ...
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88 views

What is the benefit of dual polarization in radio communication?

Why are some PtP antennas and radio units connected by two feed lines -- one for horizontal polarization and one for vertical polarization? I know the difference is in the orientation of the electric ...
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1answer
31 views

About discrete time model for wireless channel

I am trying to understand Section 2.2.3 of the book "Fundementals of wireless communication" by Tse and Viswanath. In this section the authors explain how to go from the continuous time ...
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2k views

What is the meaning of dBi?

When we say, for example, an antenna has spec of 22 dBi; Does it mean that its power is 22 dB stronger for any point at fixed direction than if it were to emit spherically?
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12 views

LTE FDD and TDD bands

Can an LTE band whether TDD or FDD in a user end (the mobile phone) be used for only one direction, i.e. only to transmit or only to receive?
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13 views

Integration of PSD (Doppler Spectrum)

The expression for received signal PSD corresponding to a simple cosine wave (frequency fC) being transmitted is given as: \begin{equation} S_r(f) = \mathcal{F}[A_r(\tau)]=\begin{cases} \frac{...
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2answers
166 views

How exactly does a basic EMF sensor work?

Halloween is coming up, and inspired by the simplicity of this project, I'm asking for a more technical explanation (and / or resources to do that) - this seems to be either missing or too obvious to ...
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9answers
2k views

Why doesn't wireless transmission and reception require a common reference voltage

so I have been struggling with this for a while now. I have tried to search for the answer but haven't succeeded yet. Here is how it goes: If we take USART as an example for wired communication ...
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1answer
134 views

Is Lora maximum transmission 1 km in real?

I'm new to wireless communication and Lora. I'm using Lora Ra-02 and Arduino UNO and small 800 Mhz antenna. I'm using Arduino website library. How can I increase that range? What do I need to do to ...
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8 views

MIMO suitability for CP-OFDM and DFT-OFDM

Is CP-OFDM more suitable for MIMO than DFT-OFDM? In both schemes orthogonal subcarriers are modulated directly by symbols and by the DFT of these symbols respectively, so I was wondering if MIMO ...

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