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.

Filter by
Sorted by
Tagged with
3 votes
3 answers
262 views

Is it viable to send electricity through glass?

I know that there is a way to induct electricity with electromagnetic field. I also know that is the part of physics used by wireless phone chargers. I have basic understanding of physics and some ...
1 vote
0 answers
16 views

Antenna Trace Impedence matching

I'm developing a wireless board. Datasheet suggests to use an external UFL antenna 50ohm Trace impedance. UFL socket which I selected is having 50 ohm impedance. So should I offer 50ohm trace ...
0 votes
0 answers
62 views

Magnetic charging

I have a question about magnetically charging devices and would like to see if anyone can help. I understand we have things like cell phone chargers that wirelessly charge using inductive technology, ...
0 votes
0 answers
7 views

Acquiring the PSS & SSS: from a UE perspective

I have been reading LTE materials of late and stumbled upon the process of UE initial procedures to attach to the LTE network. The procedure starts with searching a suitable cell. The UE first scans ...
0 votes
0 answers
12 views

Layer Mapping & Antenna Ports in LTE PDSCH layer processing

I am reading LTE materials recently, and came across the antenna port term. I am quite clear about the term, however, what does a layer mapping exactly mean? Does 'layer' correspond to a logical ...
2 votes
1 answer
52 views

NRF24L01: SPI communication only writes zeros to registers

I am trying to write simple code for transmitting with the NRF24L01 wireless chip, but the SPI communication is not going very well. Using the code below I can read any register on the NRF24L01, ...
0 votes
1 answer
24 views

CSFB service vs SRVCC service - LTE basics

I have been reading core architecture topics on LTE. In a session, I was introduced to CSFB, as a service handover, instead of the coverage handover associated with the SRVCC. While I am able to ...
1 vote
3 answers
152 views

Using antenna instead of an AC source on the circuit diagram

Here's an LNA circuit I found on google: Can I replace the AC source with an antenna?
0 votes
1 answer
63 views

Is a LNA necessary in RF receiver circuits?

Is it possible to receive signals properly from the transmitter within a short range without a low noise amplifier in the receiver, or does the LNA provide more than power amplification, like helping ...
0 votes
1 answer
50 views

Why does an optical channel require non-negative and real signal to transmit?

I'm trying to find an answer to two questions. In most of the papers they use the term without further explaining the reasons. Why does intensity modulation require real and non-negative signals to ...
0 votes
2 answers
161 views

My Tesla coil is not working

I made a Tesla coil, but it doesn't not work. I used this circuit: I used 200 turns for the primary coil with 0.5 mm wire and 5 turns for the secondary coil with 1 mm wire on a wooden rod. Back to ...
  • 67
1 vote
2 answers
106 views

What do I need to make my receiving coil work?

I’m working on a wireless energy LEF idea for a buddy's kid who wants to light up his models. I got the base station with the transmitting coil working and the wireless LEDs I got to work as intended. ...
1 vote
0 answers
40 views

How to generate PWM from based on an AC signal?

I'm working on a project to improve the efficiency of the resonant wireless charging system. For one of the steps to do this, I need to find the phase shift between current and voltage and of \$I_{\...
0 votes
0 answers
37 views

What is the difference between sleeve dipole and patch antennas, apart from ease of manufacturing and low cost? [duplicate]

Why are patch antennas used instead of dipole antennas? If we want our dipole antenna to be more directive ,we can add a ground plane that acts as a reflector or print the dipole on a substrate to ...
1 vote
1 answer
131 views

Why are patch antennas used instead of planar dipole antennas?

As far as I know, the major advantage of patch antenna over dipole antenna is its directivity. If the planar dipole antenna can achieve the same directivity then why do we use patch antennas? Are ...
0 votes
0 answers
56 views

HDMI debug issues over wireless

I have designed board that carrier transmitter HDMI module. There are TX side and RX side, the board works well except one issue that which takes a lot of sleepless days from me. this is the ...
  • 129
0 votes
1 answer
57 views

Why is channel DC gain sufficient to model optical wireless communications?

I came across the following question at ResearchGate, but I fail to comprehend the answer to it. The question states: Why do we only study the DC gain in VLC channel modeling? In all the papers and ...
0 votes
1 answer
42 views

Singular Value Decomposition MIMO

Singular Value Decomposition in MIMO Spatial Multiplexing requires knowledge of the channel state information at both the transmit and the receive and allows parallel independent data streams to be ...
  • 343
0 votes
0 answers
11 views

2x2 MIMO communications, SNR, and data throughput vs link robustness trade off

With information about data throughput in a 2x2 MIMO environment and without knowing the channel state information is there a way one can reliably estimate the receive SNR based on the throughput in ...
  • 343
1 vote
0 answers
36 views

Is there any shortcut to wireless charging, preferably Qi compatible or NFC?

Qi charging is awesome, can push a lot of power from the sender to the receiver, enough to quite rapidly charge a mobile phone. I do however find the circuits to be very advanced and involve a lot of ...
0 votes
1 answer
171 views

Can I solder a wire antenna to the exposed PCB antenna of a BBC Micro Bit to boost its bluetooth signal?

Can I solder a wire antenna to the exposed PCB antenna of a BBC Micro Bit to boost its Bluetooth signal for both transmitting and receiving data? Can I solder this type of 2.4G antenna to boost the ...
0 votes
0 answers
42 views

Why don't you see UWB location systems running at lower frequencies?

Just something I was curious about. I was recently working with an indoor UWB tracking module and the frequency ranges are 3-6GHz. But there isn't anything at say 433MHz or lower which would better ...
  • 1,727
0 votes
2 answers
96 views

Unintentional Beamforming

Suppose I have two cross polarized transmit antennas sending the same signal in a rather line-of-sight dominated environment to a receive antenna, is there any chance of creating unintentional ...
  • 343
0 votes
1 answer
44 views

Multipath destructive and constructive fading and the law of conservation of energy

Multipath in a Rayleigh fading environment causes fading, this fading could be destructive or constructive at a certain point or location in the far field, how does that align with the law of ...
  • 343
0 votes
2 answers
77 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
0 votes
2 answers
59 views

Could the electromagnetic field (EMF) from a power station disrupt wireless signals?

I know that power stations can generate an electromagnetic field, but is that field strong enough to disrupt nearby wireless signals, such as Wi-Fi, Bluetooth, cell service, etc? I'm sure that, in ...
  • 103
3 votes
2 answers
282 views

Why does the quality factor include 2*pi?

The quality factor is defined as the ratio of stored energy and dissipated energy (see below). The formula includes \$2\pi\$ as a constant coefficient. Why do we need \$2\pi\$ to calculate the stored ...
0 votes
2 answers
55 views

Coding and SNR gain

How does coding reduce the amount of SNR required to detect data for a certain modulation and at a certain bit error rate and does that imply that coding reduces noise power?
  • 343
1 vote
1 answer
61 views

Unreliable wireless comunication between 2 arduino boards

I am facing a strange and very frustrating issue while realizing a basic radio comunication between 2 arduino boards, one Arduino Nano and one Arduino Uno. For such a purpose, I am using the NRF24L01 ...
1 vote
0 answers
33 views

Antenna mutual coupling and estimation of angle of arrival

If I have two RX (receive) antennas at a distance of lambda/2 from each other there is a formula which relates the phase difference to the angle of arrival. The formula is however assuming no mutual ...
  • 343
30 votes
2 answers
5k views

Why can't USB-C receivers be as small as their USB-A counterparts?

We're all familiar with the USB-A 2.4 GHz receivers from companies like Logitech that are absurdly small and barely protrude from the port. But when looking at available USB-C equivalents, they are ...
  • 411
0 votes
1 answer
78 views

Wireless charging IC

I am building this wireless IC circuit and I don't understand the term HOST, TRI-STATE an BI-STATE. What do they mean?
0 votes
0 answers
35 views

Max range between Bluetooth 5 LE device and a smartphones

What is the maximum range achievable between a Bluetooth 5 LE device and a smartphone? This would be assuming ideal outdoor condition with no obstacles etc. The amount of data to be transferred is ...
  • 1
3 votes
1 answer
172 views

Is there sufficient 'ambient hum' to obtain a 60/120 Hz reference wirelessly?

In a typical urban (USA etc) setting, we seem to be awash in 'powerline hum'. Has it been done, or could it be practical, to recover this to get a wireless reference for a battery-powered system, like ...
  • 213
1 vote
1 answer
241 views

How to send a large amount of data via LoRa

I'm trying to implement a LoRa communication between two devices (master and slave). I studied two modules that seem to be interesting RFM96WE and SX1276. From the ...
1 vote
0 answers
54 views

How should I understand this interpretation?

Studying spatial diversity in telecommunication engineering (Fundamentals of Wireless Communication, D. Tse and P. Viswannath), I read this paragraph. $${\text {In}}\,{\|}{\textbf h}{\|}^{2}{\text {...
  • 11
0 votes
0 answers
62 views

When running a wireless charging circuit, my power supply whines and the transistor gets super hot even though everything works, is anything wrong?

I created a wireless LED power circuit to drive adafruit wireless LEDs.The circuit works great, LEDs are fully lit but my desktop power supply lets out an awful whine whenever its running (it normally ...
0 votes
0 answers
32 views

Confusion about MIMO (spatial multiplexing) in Rayleigh fading

A Rayleigh fading channel is supposed to be constituting a rich scattering environment thus suitable for spatial multiplexing, yet Rayleigh fading BER performance is very bad when compared to an AWGN ...
  • 343
0 votes
0 answers
64 views

Wireless real-time control of RGB led strip using PWM and RF

I would like to send three 8-bit PWM values (generated using an ESP32 and the ledc library) wirelessly in real-time. From what I've come across, RF seems like a good option, however I would prefer not ...
  • 1
1 vote
3 answers
93 views

Interference effects on a wireless signal

I am trying to get my head around the effects of interference on a wireless signal and its signal strength. I do not have an engineering background, but I do have a background in wireless sensor ...
1 vote
2 answers
67 views

Best way to secure MMCX jack-to-jack adaptors?

I'm currently using an MMCX jack-to-jack adaptor to connect a wire from a transceiver to another wire from an antenna. Through this adaptor, the wires click into it. However, I would like to better ...
  • 557
0 votes
1 answer
88 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 ...
  • 15
0 votes
0 answers
22 views

Bluetooth pairing in wireless keyboard

I am trying to create a wireless USB keyboard. Currently, I have all the USB output information coming from a microcontroller and into an EFR32BG1 bluetooth chip and I have a BT851 USB transceiver to ...
1 vote
1 answer
154 views

Proof of Shannon capacity theorem

I was looking for a formal proof of the Shannon capacity theorem, which states the condition which is the maximum data rate possible between two wireless channels. I could not find the proof. Does it ...
  • 147
0 votes
0 answers
42 views

How would I make a wireless pressure switch for turning on and off a flash light?

I want to make a wireless pressure switch for a flash light mounted on an airsoft gun I have figured out that I would have to use an RF transmitter/receiver like this one: https://www.amazon.com/3-7-...
1 vote
1 answer
58 views

Estimating Received Signal Strength of a DTV transmitter

Goal: Estimate the received signal level in dBm (where 0 dBm corresponds to 0.224 volts) on a spectrum analyzer for a given TV transmitter. Scenario: I have many details on the transmitter, including ...
0 votes
1 answer
153 views

Are there any noise cancellation algorithm used in wireless communication? if so in which layer?

I understand that there are 7 layers in the OSI model. I would like to know is there any noise cancellation algorithm used in wireless communication? If so in which layer is it used? I am looking for ...
  • 147
0 votes
1 answer
54 views

Question regarding bandwidth of digitally modulated signals

Assume that there are two carrier frequencies, 20 GHz (RF) and 200 THz (Optical). Both of these carrier waves are modulated by a digital signal using QPSK scheme. Consider the frequency spectrum (or ...
0 votes
0 answers
78 views

Is it POSSIBLE for a wireless device to use the cellular frequencies without approval from the FCC

My question is purely hypothetical and does NOT apply to any real life scenarios. Is it possible for a wireless device to use the cellular quad band successfully without FCC approval or knowledge.
  • 77
0 votes
5 answers
180 views

How is our voice tone transmitted and received without the change of our own voice?

For example lets take mobile communication, transmitting and receiving what we speak is fine, but how does it retains different flavors of our unique voice (that is if someone who we knows speaks over ...
  • 11

1
2 3 4 5
23