Re: [Discuss-gnuradio] MRFM (Magnetic Resonance Force Microsocopy) andGNU Radio

[Jeff Brower]

Jon-

> The UW Quantum System Engineering Laboratory has written
> code for Magnetic Resonance Force Microscopy (MRFM).
> The code is available from
> 
>   http://staff.washington.edu/~jon/gr-mrfm/
> 
> Some of the code might be useful to other GNU Radio users.  On the
> FPGA side, there is a 2-stage biquad filter with 24-bit (not 16-bit)
> data path and filter coefficients.  There is also an input multiplexer
> and adder.  On the host side, there is code (in Python with SciPy)
> that transforms transfer functions, expressed as ratios of polynomials
> with floating point coeffcients, into cascaded biquad stages with
> scaled integer coeffcients.  The host side code acts as a server, so
> it can communicate with the MRFM experiment software over TCP/IP
> sockets.  There is a sample client, also in Python with Scipy.
> 
> I have put links to our site on the Wiki OurUsers and OtherCode pages.

I'm curious .. what do use the 'biquad filters' for?  I assume you mean that 
you've
implemented a 4th order IIR filter?  If so that would mean somewhat non-linear 
phase
depending on the IIR design type.  What type are you using?  Elliptic?  Other?

Thanks.

-Jeff