TOP Page > Projects > OPENCORE NMR
  OpenCore NMR
-- Open-source core modules for implementing
an integrated FPGA-based NMR spectrometer --
[ Japanese | English ]

This page only serves as a brief brochure of the project. An extensive description of this project is currently under progress.... (Unfinished link).

[Background -- an integrated FPGA-based NMR spectrometer --]
Recently we have developed integrated, FPGA-based NMR spectrometers[1]. The word "FPGA" stands for Field-Programmable Gate-Array. FPGA is a kind of semiconductor device. Its remarkable feature is that you can implement digital circuits inside an FPGA chip by writing a corresponding codes in hardware description language.

Figure 1. (a) A snapshot of an FPGA chip on a board, and (b) a schematic description of FPGA programming.

In our NMR-spectrometer development, we have taken a strategy of letting a single FPGA chip do all digital jobs required for an NMR spectrometer. As a consequence, the spectrometer has been realized (Figure 2) with such a compact size that you can put it in your bag! The integrated FPGA-based NMR spectrometer has 3 rf channels, each of which is capable of operating at up to 400 MHz, and of modulating amplitude, phase, and frequency of rf irradiation. For such parts that cannot be implemented with FPGA (e.g., non-digital stuff), peripheral circuits have been developed separately. An example of such peripheral circuits is shown in Figure 3.

Figure 2. The integrated FPGA-based spectrometer in action.

Figure 3. (a) A circuit diagram, (b) board drawing, and (c) finished product of a DDS board.

Here, a kit for implementing the spectrometer inside FPGA is to be open to public. This kit, referred to as OPENCORE NMR, is composed of core modules such as an asynchronous triple pulse programmer, a direct-digital synthesizer, a digital receiver composed of a digital quadrature demodulator and a digital low-pass filter, and a PC interface. There modules are written in VHDL, and the source codes are to be available, together with documentation describing the principle of operation. Also, resources necessary for reproducing the FPGA-based NMR spectrometer will be available, including
  (i) technical documents
  (ii) circuit diagrams
  (iii) board drawings
  (iv) control software

A home-built NMR spectrometer can serve complementary roles to a sophisticated commercial spectrometer, should one comes across such new ideas that require heavy modification to hardware inside the spectrometer. This work can lower the barriar of building a handmade NMR spectrometer in the laboratory, and promote novel and exciting NMR experiments.

[1] K. Takeda, Rev. Sci. Instrum. 78, 033103 (2007).

[People in contribution]
  <- Scene of development
Kazuyuki Takeda


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