Inner ear provides secret to better radio reception
Cochlea model for radio reception
Courtesy WelleschikA 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
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Wardenclyffe tower and building c. 1903
Courtesy Public domainIn 1901, inventor and electrical visionary Nikola Tesla began building a laboratory near New York’s Long Island Sound complete with a gigantic 18-story radio tower that he hoped would not only broadcast wireless communications to the world but also supply free electricity for everyone. His grand schemes, however, never really got off the ground. Before the year was out Guglielmo Marconi (using seventeen of Tesla’s patents) would claim to send the first radio signal across the Atlantic, and soon after, Tesla’s investors - including steel magnate J. P. Morgan - began to lose faith in the project and withheld further funding. Eventually mounting debts, lawsuits and loss of patent income began to take their toll on Tesla and his visionary plans.
Known as Wardenclyffe, the site was designed by noted architect Stanford White. It operated for a few years in the early 1900s, even serving as the inventor’s main laboratory for a time. But by mid-decade Tesla himself abandoned the site, and for years it sat unoccupied falling to ruin. Inner machinery and equipment were salvaged and sold to satisfy monetary obligations, and the massive tower was dismantled for scrap during World War I leaving only its foundation. But the main building still stands today and, despite its dilapidated state, has the distinction of being the only remaining worksite of the brilliant Gilded Age inventor.
Now a group of Tesla devotees are pushing for the site to be preserved and designated as a historical site and memorial to a man they say is worthy of a monument.
Nikola Tesla
Courtesy WikipediaTesla contributions were certainly monumental. The Serbian-born inventor held over 700 patents and introduced to the world such things as fluorescent lighting, the first remote controlled robot, x-ray photographs, and wireless communications. One invention, the Tesla coil, is still used in today’s radios and television sets and other electrical devices. One of his greatest contributions, the development of alternating electrical current (AC) technology, went against his former employer Thomas Edison's big push for direct current (DC). The threatened Edison went so far as to hire a man to electrocute dogs, old horses, and even a rogue elephant(!) to show the public the dangers of AC current. But AC’s superior technology proved more efficient and cheaper, and near the end of his life, Edison admitted Tesla had been right.
Tesla in his element: Typical promotional photo of the inventor
Courtesy Public domainTesla was a bit of a showman when it came to promoting his inventions and theories, often portraying himself in composite photographs sitting peacefully in a display of electric current. During the height of his career he was a wealthy and dapper household name who hobnobbed with the scientific, artistic, and political elite of his day, and had several laboratories in the New York area. In the late 1890s he set up a lab in Colorado Springs to supposedly “transmit a radio signal from Pikes Peak to Paris”. With funding from Colonel John Jacob Astor (who later went down with the Titanic), Tesla built an 80-foot tower on the prairie for that very purpose. Whether or not he achieved his objective remains a mystery, but he and his assistant did manage to put on quite a lightshow for Colorado Springs residents. Reportedly, the tower discharged a high-voltage flurry of 145-foot sparks in every direction that subsequently blew out the power for the entire town. After nine months of experiments, he abandoned the lab and returned to New York to continue his experiments at Wardenclyffe. The Colorado Springs facility was eventually torn down and sold for scrap and no sign of it remains today,
A consortium of science enthusiasts, preservationists, and plain old fans of Tesla’s genius want the Wardenclyffe facilities preserved as a national monument and museum. The group includes Tesla biographer Marc Siefer who helped pen a letter to President Obama asking for the necessary funds to purchase the 10,000-square foot brownstone structure and surrounding acres from the Belgium-based Agfa Corp, which is eager to sell the property to soften the effects of the present economy.
But Siefer and his colleagues think Tesla’s many accomplishments warrant its preservations. For one thing the group contends it was Tesla - not Marconi - who was the true inventor of wireless radio. The issue of who owned the patents for radio broadcast has gone back and forth since the early 20th Century. In 1904 the US Patent Office ruled in favor of Marconi for the patents even though it had ruled in Tesla’s favor in the prior year. Marconi’s many powerful investors may have been the reason for this. After Marconi won the Nobel Prize in 1909 the furious Tesla sued him for infringement and lost again. But in 1943, the US Supreme court proclaimed Tesla was the inventor (probably because the Marconi Company was suing the US government for infringement of the same patents). Unfortunately, for Tesla, this final designation came two months after his death.
Even today, Tesla still seems to elude proper recognition, but Marc Seifer and his colleagues hope to change that by acquiring and preserving Wardenclyffe, a site they say has great historic significance as the last remaining trace of the eccentric inventor’s once grand vision.
“It’s hugely important to protect this site,” Seifer said. “He’s an icon. He stands for what humans are supposed to do — honor nature while using high technology to harness its powers.”
Watch a YouTube video detailing Tesla's life and accomplishments.
LINKS
Tesla Memorial Society of New York website
NY Times Wardenclyffe story
PBS Tesla site
War of the Currents
1899 Tesla interview
Belgrade Tesla museum
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
Courtesy 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
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.
- Good Vibrations (Quicktime, 8.06 MB)
- Star Wars (Quicktime, 8.68 MB)
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