Is it possible to construct such a computer peripheral device?

[somega]

There are many wireless communication standards like:
- WiFi
- DVB-T /DVB-A
- LTE
- FM broadcasting

As far as I know they are all using electromagnetic waves.
And if they are all sending then the electromagnetic field amplitude is the combination of them all.
Is it possible to construct a computer device (e.g. USB stick) which measures the electromagnetic amplitude (without filtering for a frequency)?
A computer program could then filter the signal for a specific frequency/standard.
This would mean you have 1 USB stick which can receive any kind of wireless communication standard.

 

[berkeman]

Good question -- keep on thinking like this!

Several issues:

• Efficient antennas are about the size of the wavelength of the EM. So it's hard to use a single antenna for broadband reception
• The broader your initial RF receive preamp's bandwidth, the more noise you also pick up. It's generally best for obtaining a good signal/noise ratio (SNR) to do narrow band filtering of the input signal (often with a passive resonant circuit right after the receive antenna), and then do your mixing and processing after that. It's very hard to make an RF receiver with good sensitivity if you try to make it too broadband.
• There are "software defined radios" (SDRs) that are pretty interesting. They aren't necessarily broadband, but they are generally pretty flexible. Do a search and some reading about them to learn more.

 

[Tom.G]

Something very similar is on the market and called "Software Defined Radios", starting price is USD $4 .

Google finds over 15 000 000 results!
https://www.google.com/search?&q=software+defined+radio+receiver
Cheers,
Tom

 

[davenn]

Something very similar is on the market and called "Software Defined Radios", starting price is USD $4 .

Google finds over 15 000 000 results!
https://www.google.com/search?&q=software+defined+radio+receiver
Cheers,
Tom

see Berkeman's post

 

[essenmein]

The other issue is to interact with something like a wifi or LTE network you need both transmit and receive, and generally you need to register on the network, so fundamentally quite different from FM radio and digital TV which are one way (large transmitter, lots of little receivers).

 

[Rive]

Is it possible to construct a computer device (e.g. USB stick) which measures the electromagnetic amplitude (without filtering for a frequency)?
A computer program could then filter the signal for a specific frequency/standard.

Just think about the requirements for processing power and IO/memory bandwidth for continuous operation. I did not delve too deep into the math but just a single upper limit check said that a barely adequate sampling for LTE g4 would consume a whole PCIe3.0 X8 slot. Just forget about any sticks here

BTW the math exists and for audio or low frequency (the 'low' here is subject of relativity) signals the method works.