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Re: [Discuss-gnuradio] using GNU Radio for research?

From: w_esco_m
Subject: Re: [Discuss-gnuradio] using GNU Radio for research?
Date: Sat, 20 Dec 2003 11:30:38 -0800

Dear Seth:

I am hoping to do this at some point in the near future. We use lasers to detect individual molecules, and the signal-to-noise requirements are extremely severe. See http://www.stanford.edu/group/moerner/research and also L. Kador, D. E. Horne, W. E. Moerner, "Optical Detection and Probing of Single Dopant Molecules of Pentacene in a p-Terphenyl Host Crystal by Means of Absorption Spectroscopy," J. Phys. Chem. 94, 1237 (1990).

In the past, I have detected single molecules with fluorescence and with laser FM spectroscopy, and we are now working on optical Sagnac interferometry to see if a new method can be added to the mix. The rf detection problem consists in detecting weak, possibly modulated rf signals in the MHz range that result from optical detection of lasers probing the sample. Often rf excitation (transmit) is not used, but I can imagine scenarios where the transmitter signal might be used to pump the molecules in a special way, which might produce a more detectable signal on the receive side. In particular, spread-spectrum excitations and detections have already been used for laser spectroscopy. See K. P. Dinse, M. P. Winters, J. L. Hall, "Doppler-free optical multiplex spectroscopy with stochastic excitation," J. Opt. Soc. Am. B 5, 1825 (1988). The difficulty lies in the fact that we are already at the quantum limit, so new schemes have to be extremely good.

The gnuradio project potentially provides extreme flexibility in the digital processing of signals for ultimate detection at reasonably high data rates, and my graduate students with the proper background could alter the programming as needed. I have not yet purchased the high-speed ADC that is required, since USB2.0 interfaces were potentially in the works, and naturally, this is mostly a hobby. But in the end, I hope to use it for research.

73 Weo  WN6I  Prof. W. E. Moerner

At 03:30 PM 12/19/2003 -0800, you wrote:
While it can be argued -- and has been argued -- that all current uses
of GNU Radio are research uses, I am interested in hearing from people
who think of themselves as using GNU Radio in traditional research or
teaching roles, particularly at academic institutions.

The FCC has issued a Further Notice of Proposed Rulemaking in its
broadcast flag docket, with comments due January 14 and reply comments
due February 13, on issues including the status of software radios
under the broadcast flag rule.  I would like to be able to describe
some of the benefits in speech, science, engineering, and education
that are resulting from the GNU Radio project.  If you can help, I
would appreciate it very much.

(The FNPRM is buried inside the FCC's Report and Order issued in
November, which deferred and sought further comment on software
radios.  There are many likely arguments from the movie industry, but
one is: _Other_ software radios don't come with source code or
encourage the public to experiment, why does _yours_ have to?)

Seth David Schoen <address@hidden> | Very frankly, I am opposed to people
     http://www.loyalty.org/~schoen/   | being programmed by others.
     http://vitanuova.loyalty.org/     |     -- Fred Rogers (1928-2003),
                                       |        464 U.S. 417, 445 (1984)

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