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 Frequency). Distances can be as low as centimeters (e.g. RFID); there's no upper limit.

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What exactly does the limiter do in FSK demodulators?

I wonder what exactly the limiter does in FSK demodulators. What are the advantages? Could it be just a saturation in ADC or fixed-pointing stages?
0 votes
1 answer
71 views

How do I convert a differential RF signal to a single ended signal? [closed]

I'm using an RF transceiver that has a differential pair output. I want to route it to an SMA connector. How do I convert the differential signal to a single ended signal?
0 votes
0 answers
39 views

Is my rough design of wireless powered leds with a capacitance touch sensor reasonable?

Disclaimer: I am not an engineer, but I have a background in physics, so theoretically I should know most of this stuff, but in reality, I might have made some very basic and dumb mistakes. The ...
0 votes
1 answer
220 views

Beamforming antenna beamwidth/frequency relation

What's the relation between the minimum beamwidth and frequency of a beamforming antenna (such as a MIMO transmitter)? I'd guess they'd have to be on the same order? $$ \lambda \propto BeamWidth \text{...
1 vote
1 answer
442 views

What is Channel Vector?

When I read research paper, there is a word named "Channel Vector". I think it is too abstract, so it is hard to understand for me. What does it mean? For example: Consider the downlink ...
1 vote
2 answers
70 views

Is BPSK better than QPSK in any way?

I wonder why there are still some modems using BPSK as their modulation. Is there any benefit over QPSK (power, bandwidth, synchronization techniques, etc.)? I have been searching and found these: ...
5 votes
1 answer
1k views

LTE UE REPORTED CQI - Defined by RS-SINR or by Transport Block Mapping?

First than anything, let me assure you I am fully aware that no one REALLY knows HOW UE manufacturers specifically implement the CQI reports sent on the UL, but there should certainly be a better ...
0 votes
2 answers
211 views

How to determine the radiation pattern of a receiver antenna

I am designing a receiver antenna for a wireless power transfer application. The transmitter is a 2m x 2m horn antenna array that transmits a power signal at a frequency of 35 GHz from 100 meters away ...
-1 votes
2 answers
256 views

What is the relation between bandwidth and data rate?

If I have a 20Mhz bandwidth provided by my 2.4ghz router then will my internet speed will be 20M symbols per sec which is equal to 20×4= 80Mbps (considering 16 qam modulator with 4 bits per symbol) Is ...
2 votes
1 answer
216 views

How are simultaneous transmissions decoded at the receiver?

I am finding it hard to understand how does a receiver differentiate between the interference and the signal intended for the corresponding receiver. For example in a case where two user pairs are ...
0 votes
1 answer
61 views

Making a USB connection over WIFI [closed]

I have been using wired Carplay/Android Auto in my car. I checked a few existing wireless auto solutions and realised the present solution has a complete system inside to handle the connection. This ...
0 votes
0 answers
71 views

Help with exploring the possibiltiy of "long distance" wireless charging

I have a question regarding the possibility of wireless charging (via coils and pads.) Essentially, I am trying to develop a product that will require charging from a car's battery and will be placed ...
0 votes
0 answers
44 views

Why do we get increase in BER with increase in Eb/N0 of the signal?

I'm working on a problem of MSK modulation scheme. I have passed my modulated signal through SUI channel Models and AWGN. But As I want to do analysis on the performance of SUI channels I'm getting ...
2 votes
2 answers
255 views

How to compute the energy efficiency in bits/s/watt

The energy efficiency (EE) in wireless communications is usually calculated as the ratio of data rate to power consumption: how many data (in bits per second) are delivered per consumed power (in ...
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0 answers
123 views

Can I connect my own hardware to a universal 2.4GHz RF wireless receiver?

I built a USB keyboard for PC with a microcontroller, and it works great. The next challenge is to do it wirelessly. I have seen that sell universal 2.4GHz RF to USB wireless receivers, similar to ...
0 votes
2 answers
107 views

Whats the point of the feedhorn on a dish antenna, why cant the dish just have a matching network attached to the dish directly?

Apologies if any thing i have said is incorrect. But, in the context of antennas, an unmatched feedpoint often leads to reflections, impacting both transmission and reception. It appears that if the ...
0 votes
2 answers
327 views

Passive Infrared (PIR) Motion Sensor

I want to have the PIR Motion Sensor: https://www.adafruit.com/product/189 Used to turn on a light whenever it detects motion. Simple enough, but would it be possible to have this done wirelessly? ...
0 votes
1 answer
252 views

Some questions regarding the SPI configurations to interface with nrf24l01 radio transceiver

I am looking at the product spec of nordic nRF24L01 transceiver module and trying to figure out how I can use with the STM32's SPI. The MCU that I have is STM32F4 nucleo and it's got 4 SPI peripherals ...
0 votes
1 answer
30 views

Wireless programming of MCU in liquid [closed]

Which methods can be used to program the device in a liquid reservoir (high voltage insulating oil) wirelessly quickly and safely? There will be a distance of 3-5cm between the programmer block and ...
0 votes
0 answers
79 views

Designing a circuit for wireless interrogation of a temperature SAW sensor

I'm currently working on a SAW-based temperature sensor. The gist of how it works is this: when the external temperature changes, the resonance frequency of the SAW resonator shifts. To detect the ...
0 votes
0 answers
56 views

Send wireless signal from a wireless relay to turn a wireless lamp on

I have this wireless relay: The receiver is connected to a pump which is on the 1st floor of our house and can be controlled from the 3rd floor of our house. We have a neighbor (my sister) who can ...
2 votes
1 answer
64 views

Non-contact powering of LED indicator from a high voltage cable

We manufacture fireproof power plugs for high-voltage transformers used in mines. The way it works is we take the incoming single-phase cable and epoxy it into the plug and attach it to the ...
0 votes
1 answer
943 views

SIM800L disconnecting issue

I'm doing a project using a SIM800L eBay module. I can send and receive SMS & calls. The problem is that on the workbench it's working, but in an actual site environment, when the GSM signal is ...
0 votes
1 answer
65 views

What is optical wireless communication? [closed]

What is the term optical wireless communication? According to my point of view, in optical communication there msut be a medium so the refractive index should be capable of keeping the wave inside the ...
0 votes
0 answers
56 views

Adalm Pluto SDR - Second RX channel signal issues

I have a Pluto SDR rev c, on which I just enable the second TX and RX channel. I am sending a simple sinusoidal signal at a specific frequency (fc), but different phase and amplitude, using the two TX ...
0 votes
2 answers
2k views

HC12 Serial RF Transceiver with PIC16F886 Microcontroller

I'm trying to do a wireless communication between two PIC microcontrollers (PIC16F886) using the TX/RX lines using HC-12 RF transceiver modules (datasheet link below). https://statics3.seeedstudio.com/...
0 votes
0 answers
21 views

Inductor based or switched capacitor DC-DC converter for given load parameters for mouse's headstage

For my master's thesis project, which focuses on designing a control loop for a DC-DC converter in the receiver of a resonant inductive coupling system to handle significant and unpredictable ...
1 vote
1 answer
2k views

RFID tag emulator

I'm having a hard time figuring out how to emulate 13.56Mhz RFID Mifare tags using an Arduino and basic components. I have tested some ideas but I couldn't read bytes due to difference in protocols ...
2 votes
2 answers
488 views

Alternative wireless technology for passive RFID tags

I am working on a project where I have 3 boxes and a RFID reader (MFRC522) attached at the bottom of each box. I keep my wallet/keys/etc. in these boxes and an LCD screen displays what is in each box ...
0 votes
1 answer
53 views

How to enable short distance data transmission between two devices without BLE or infrared communication capabilities [closed]

I have two devices, neither of them have BLE (Bluetooth Low Energy) or infrared communication capabilities, but I would like to be able to transfer data between them over short distances. I know we ...
1 vote
1 answer
554 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 ...
0 votes
2 answers
57 views

Small Wireless RGB LED Controller

We want to make a wearable accessory with at least one color-changing rgb led that you can set the color of by connecting to it wirelessly from a phone or computer. As this would be something to wear, ...
0 votes
0 answers
73 views

NRF24L01+ questions

Hello I have bought 2 NRF24L01+ (for instance: https://www.addicore.com/products/nrf24l01-pa-lna-with-antenna-2-4ghz-wireless-transceiver) in order to make a link between 2 Arduino. I am searching ...
3 votes
0 answers
97 views

Resonant Coupling for Optimal Power Transfer

I am trying to read the following paper: B. L. Cannon, J. F. Hoburg, D. D. Stancil and S. C. Goldstein, "Magnetic Resonant Coupling As a Potential Means for Wireless Power Transfer to Multiple ...
0 votes
1 answer
237 views

Trying to read the data from an ASK RF transmitter

I'm trying to duplicate the operation of a simple RF remote control (for some remote power outlets). In the remote control there is an unmarked 8-pin microcontroller. I've worked out which pins are ...
0 votes
0 answers
44 views

How to shield a wireless microphone receiver from hdmi cables running under it?

We have some wireless microphones set up with the receivers in a confined space. After adding some HDMI cables (for streaming purposes) we now have an interference problem. While the transmitter is ...
0 votes
2 answers
65 views

What's wrong with the tx circuit?

Whenever I connect the power source, the transformer heats up, measures 0v AC and rectifier doesn't measure any voltage in DC. I feel there are components I need to add to the tx circuit. I'm trying ...
1 vote
0 answers
71 views

What is the maximum relative speed at which wireless protocols can operate? (Doppler shift)

Let's take Wi-Fi and UWB. What determines in these standards their robustness to Doppler shift? The most obvious is the range of carrier frequency tolerance. But in both standards this range is ...
0 votes
0 answers
121 views

Untraceable datasheets of DC-DC buck converter (5 pin SOT23-5 IC) used in TP-LINK WiFi Router TL-WR720N V2

I am trying to search the datasheets of DC-DC buck converters used in the TP-LINK WiFi Router TL-WR720N V2. LD5AX and TR5XF A couple of years ago, an above mentioned router, belonging to one of my ...
1 vote
2 answers
214 views

Need advice on achieving 1 km non-line-of-sight wireless communication without internet

I'm currently working on a project that involves establishing a reliable non-line-of-sight wireless communication link with a range of 1 kilometer or more. The project does not have internet access, ...
3 votes
2 answers
389 views

WiFi/BT on Realtek 8723 - Is FCC, CE certification needed for WiFi if we disable WiFi and use only Bluetooth?

I'm planning on importing a generic mini pc that comes with an onboard Realtek 8723 for WiFi and Bluetooth. We will need to get it FCC, CE, and IC certified before we sell it in North America/EU. ...
2 votes
0 answers
36 views

What is the ideal wireless protocol that is best suited for wireless nerve impulse transmission? [closed]

I am working to develop a way to transmit nerve impulses wirelessly (or wired) past a break in the spinal cord. What would be the ideal protocol to effectively relay the signal? Even if the device was ...
4 votes
1 answer
288 views

Sensing an object’s motion using a motion sensor inside the object?

I am considering making a mouse that you can essentially use in the air. It would be wirelessly connected to a computer/laptop, and you could move it through the air to track motion in the mouse. It’s ...
0 votes
1 answer
50 views

Books/Material for RF transmitter/receiver design [closed]

I am doing my thesis for my BSc in EE. Due to a lack of equipped laboratories in my universities, I cannot do a project in microwave-integrated circuits, as I would have preferred. I am therefore ...
0 votes
3 answers
2k views

Is wireless power transfer by induction at 60Hz possible, or does the frequency need to be changed?

I want to build a wireless power transmitter that works over a very short distance. Can I use my line voltage(120V at 60Hz) through the primary coil to induce voltage into a secondary coil about 1/4" ...
5 votes
2 answers
1k views

Can wireless charging become more energy efficient?

I've stumbled upon a few articles saying that wireless charging takes more energy to charge something compared to the cable. Like this one. Like in the test from the article, it takes 47.33 % more ...
1 vote
0 answers
54 views

How do you find Image Rejection Ratio from doing FFT on ADC samples?

I'm trying to understand a particular code written by a former employee for measuring performance of an RX chain in a transceiver. I have to measure IRR(Image Rejection Ratio). Certain input RF ...
2 votes
0 answers
61 views

Information sources to design a spiral PCB antenna

I am starting a huge experimental project and I want/need to explore the frequency independent antennas. I settled on two very interesting antenna topologies that are possible to design as a PCB (...
1 vote
0 answers
28 views

How wireless charger automatic detect Rx Coil to turn on

I want to know how wireless charger can detect 2nd coil then the switching at 1st coil is on, but when the 2nd coil isn't detected by 1st coil, the switching at 1st coil is turn off. How it happens? ...
0 votes
1 answer
80 views

Bluetooth trilateration using nRF5340

I am a total beginner in working with RTOS and Zephyr and nRF devices. I would like to build a Wireless Sensor Network which consists of 3 nodes (maybe set in a Bluetooth Mesh) whose primary objective ...

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