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Electronics => Microcontrollers => Topic started by: NateDuong on July 03, 2015, 06:34:09 pm

Title: RF lab set up ...
Post by: NateDuong on July 03, 2015, 06:34:09 pm
Dear everyone...

I am trying to set up a RF lab at home to help me do DSP projects with very low frequency, as low as possible.

Anyone who has experiences about RF lab, please give me some ideals and what machines from basic to advance will be needed for the lab?

Thank you,

Nate Duong.
Title: Re: RF lab set up ...
Post by: mazurov on July 03, 2015, 06:40:22 pm
You meant 'high' frequency, not 'low', correct? You can detect RF with a diode, it will be very cheap. The oscilloscope/probes need to be rated for 10x the frequency of interest if you want to see well in time domain.
Title: Re: RF lab set up ...
Post by: NateDuong on July 03, 2015, 07:36:50 pm

I meant "low" frequency such as heart beat...so there is no way to measure it?
Title: Re: RF lab set up ...
Post by: T3sl4co1l on July 03, 2015, 07:40:31 pm
"RF" broadly means electromagnetic radiation, at frequencies able to be carried in wires and radiated through space; very loosely, 100kHz to 100GHz or so.

You can do "RF" at ELF (< 10kHz), but it's considerably more difficult.

Heartbeats have nothing to do with RF; perhaps you're confusing abbreviations?

Tim
Title: Re: RF lab set up ...
Post by: JoeN on July 05, 2015, 07:26:20 am
Quote from: T3sl4co1l on July 03, 2015, 07:40:31 pm
Heartbeats have nothing to do with RF; perhaps you're confusing abbreviations?

Perhaps he will be the first person to be able to detect heartbeats from radiated EMF rather than electrodes.  Now how cool would that be?    :P
Title: Re: RF lab set up ...
Post by: hendorog on July 07, 2015, 06:17:43 am
Quote
Perhaps he will be the first person to be able to detect heartbeats from radiated EMF rather than electrodes.  Now how cool would that be?    :P

He won't be the first. I remember reading a few years ago about a trial of a system which could detect people trapped under rubble after an earthquake. It detected respiration and heartbeat - RF goes all the way to DC :)
Apparently it was used for real in Nepal after the recent quake there.

Google found all these:
http://www.academia.edu/5382185/Contactless_Detection_and_Analysis_of_Human_Vital_Signs_Using_Concurrent_Dual-Band_RF_System (http://www.academia.edu/5382185/Contactless_Detection_and_Analysis_of_Human_Vital_Signs_Using_Concurrent_Dual-Band_RF_System)
https://www.youtube.com/watch?v=Lpwtwv5q960 (https://www.youtube.com/watch?v=Lpwtwv5q960)
http://www.ncbi.nlm.nih.gov/pubmed/19964829 (http://www.ncbi.nlm.nih.gov/pubmed/19964829)
http://nyuwireless.com/ThePulse/03/Heart-Rate-Measurement-Utilizing-Non-Contact-RF-Detection-From-Within-The-Mouth.php (http://nyuwireless.com/ThePulse/03/Heart-Rate-Measurement-Utilizing-Non-Contact-RF-Detection-From-Within-The-Mouth.php)
http://fox41blogs.typepad.com/wdrb_weather/2015/05/nasas-radar-found-4-men-trapped-under-rubble-in-nepal-by-their-heartbeats.html (http://fox41blogs.typepad.com/wdrb_weather/2015/05/nasas-radar-found-4-men-trapped-under-rubble-in-nepal-by-their-heartbeats.html)

Title: Re: RF lab set up ...
Post by: Alexei.Polkhanov on July 07, 2015, 06:26:40 am
I think I got it. He is talking about Doppler radar systems that are used by police for example to detect if there is anyone in a room behind a wall etc. Those are 3GHz as far as I know and yes they can sense heart bit of human or even small animal.

http://www.range-r.com/tech/theory.htm (http://www.range-r.com/tech/theory.htm)
This one?