Thursday, January 15, 2009

Did you know?

Blogging has been light this week, but we think this post will make up for it!

Did you know that the ear (and brain) constitute a regenerative detector? [At least if Wikipedia can be trusted on this point].

From Teh Great Wiki:

The inner ear contains thousands of minute hairs, called stereocilia, which vibrate in response to sound waves and cells which convert neural signals back into acoustical vibrations. The sensing cells are connected with the vibratory cells through a neural feedback loop, whose gain is regulated by the brain. This loop is normally adjusted just below onset of self-oscillation, which gives the ear spectacular sensitivity and selectivity. [One does wonder just how many of these loops there are...]
Edwin Armstrong invented this system for Radio back in 1914.
A regenerative radio receiver is unsurpassed in comparable simplicity, weak signal reception, inherent noise-limiting and agc action and, freedom from overloading and spurious responses. The regenerative radio receiver or, even super-regenerative radio receiver or, "regen" if you prefer, are basically oscillating detector receivers. They are simple detectors which may be used for cw or ssb when adjusted for oscillation or a-m phone when set just below point of oscillation. In contrast direct conversion receivers use a separate hetrodyne oscillator to produce a signal.


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