Stories tagged radio

Watch now
Watch nowCourtesy NPR
Well, I learned about it a day too late to listen live, but NPR's Marketplace hosted a invigorating conversation on Climate and Sustainability yesterday. You can listen to audio and watch video of the event online. We need more events like this, bringing scientists and business leaders together to create a sustainable environment that works for humans in our modern economy.

Jun
21
2009

Inner ear provides secret to better radio reception

Cochlea model for radio reception
Cochlea model for radio receptionCourtesy Welleschik
A group of MIT engineers is looking to the human body for solutions to some of our technological problems. Many of us are discovering that our HDTVs or cell phones won't work without a better antenna.
Rahul Sarpeshkar, and his graduate student, Soumyajit Mandal, realized that the cochlea in our inner ear is like an antenna. In a paper titled "A Bio-Inspired Active Radio-Frequency Silicon Cochlea" (15 pg PDF) they explain that

The biological inner ear or cochlea is an amazing custom analog computer capable of the equivalent of 1GFLOPS of spectral-analysis and gain-control computations with 14uW of power on a 150mV battery and a minimum detectable signal of 0.05 angstroms. It achieves such efficiency because of the clever use of an active nonlinear transmission line implemented with fluids, membranes, active piezoelectret cells, micromechanics, and electrochemistry.The cochlea has an amazingly large input dynamic range of 120dB, analyzes frequencies over a 100-fold range in carrier frequency (100Hz-10kHz), and amplifies signals at 100kHz even though its cells have time constants of 1ms.

Mining the intellectual resources of nature

By modeling the cochlea with analagous electronic components, they created what they call an RF silicon cochlea.

The RF cochlea, embedded on a silicon chip measuring 1.5 mm by 3 mm, works as an analog spectrum analyzer, detecting the composition of any electromagnetic waves within its perception range. Electromagnetic waves travel through electronic inductors and capacitors (analogous to the biological cochlea's fluid and membrane). Electronic transistors play the role of the cochlea's hair cells.

The chip is faster than any human-designed radio-frequency spectrum analyzer and also operates at much lower power.

Looking to nature for technological solutions

This is not the first time Sarpeshkar has drawn on biology for inspiration in designing electronic devices. Clicking this link will direct you to ten papers resulting from bio-inspired projects in sensing and computing.

Source MIT News

Dec
25
2008

Greetings from lunar orbit, Dec 24, 1968

Forty years ago the crew of Apollo 8 delivered a live, televised Christmas Eve broadcast after becoming the first humans to orbit another space body.

"The vast loneliness is awe-inspiring, and it makes you realize just what you have back there on Earth," Lovell said. Wired

First public radio broadcast, Dec. 24, 1906

Speaking of famous Christmas eve broadcasts, it's worth remembering that Reginald Fessenden made what is generally recognized as the first public voice-over-radio broadcast on Dec. 24, 1906.

Radio Lab
Radio LabCourtesy WNYC

I just stumbled onto a radio show that I bet a lot of folks who read this blog are already aware of, but in case you are not... I caught the WNYC show Radio Lab for the first time on NPR a couple of weeks ago, and it is really interesting. It's a show that seems to be mostly about science (it is funded by NSF) and its interesting. The past few shows have been on race, sperm, choice and diagnosis. The show is available to download or subscribe to from their site or from iTunes. I recommend checking it out.

There was a particular part of an episode that I thought was really great. As part of their "diagnosis" show they had a part called How To Cure What Ails You. Its about 20 minutes long, and you can listen to it from the link. Its crazy interesting, I think.

The first radios (and transmitters) were home made. In 1920, Horne's department store placed an advertisement in the Pittsburgh Sun heralding the miracle that you could listen to music over the air:

Air concert picked up by radio here. The music was from a Victrola in the home of Frank Conrad. Mr. Conrad is a wireless enthusiast and puts on these wireless concerts periodically for the entertainment of many people in this district who have wireless sets. Amateur wireless sets are on sale here $10 and up. Wired

Jul
06
2008

The shrinking radio: Courtesy Zettl Research Group, Lawrence Berkeley National Laboratory and University of California at Berkeley.
The shrinking radio: Courtesy Zettl Research Group, Lawrence Berkeley National Laboratory and University of California at Berkeley.Courtesy Zettl Research Group

Tiniest radio yet

A fully integrated radio receiver, orders-of-magnitude smaller than any previous radio, was made from a single carbon nanotube (CNT).

When a radio wave of a specific frequency impinges on the nanotube it begins to vibrate vigorously. An electric field applied to the nanotube forces electrons to be emitted from its tip.

This nanotube radio is over 10,000,000,000,000,000,000 times smaller than the Philco vacuum tube radio from the 1930s.

The single nanotube serves, at once, as all major components of a radio: antenna, tuner, amplifier, and demodulator. (Berkely physics research)

See and hear a nano radio

Videos from an electron microscope view of the nanotube radio playing two different songs are linked below.