A digital NMR has been developed on basis of a Spincore radioprocessor. The Spincore radioprocessor board is controlled by Matlab using a USB 2.0 connection. Using Matlab the NMR pulse sequences are programmed to the board. Using a NI USB-6501 board variable attenuators are controlled for both the RF-out and RF-in. For  better signal-to-noise ration the power amplifier is switched by using one of the free digital output ports of the radioprocessor. In figure 1 a schematic diagram is given. An overview of complete setup is given in figure 2. We use an electro magnet for making the main field

 


Figure 1: A schematic diagram of the NMR using a spincore radioprocessor board



Figure 2: The complete digital NMR setup


MATLAB control


The NMR is controlled from Matlab. There are two version available  for each NMR sequence: a command line function and a user interface. Both can be  called from  within Matlab. An example will  be given for  the Hahn sequence.  By calling set_freq_hahn the userinterface for  the Hahn sequence is started.  A  screenshot is given in figure 3.  As can be seen using this graphical interface all parameters can be controlled.


Figure 3: The Hahn spin echo user interface.


Once using this interface the optimal parameters are found a Hahn spin-echo can also be called from Matlab script (m-file) using do_sslc_hahn. An example is:

As can be seen still all parameters can be changed from within a m-file while at the end of a Hahn-echo sequence all the data are available in structures (here data.freqx ad data.freqy). A complete manual is available with all source codes for the various sequences and user-interfaces.

DOWNLOAD: Source code (Matlab + C file of pulse sequences) + Manual