MDSP - a Multichannel Digitizer and Spectral Processor for Smallsat Radiometer Applications

This paper presents the MDSP, a modular, scalable spectrometer baseband processing unit appropriate for use in general smallsat (similar to 3U) missions. Currently, THz and GHz radiometers have one RF front-end and one back-end spectrometer. Modern technological advances have permitted the front-end receivers to be extremely compact and operate non-cryogenic. However, to meet the needs of Ionospheric Thermospheric Mesopheric (ITM) and Magnetospheric-Ionospheric (M-I) coupling sciences, one needs multiple THz and GHz sensors, making a scalable Size, Weight and Power (SWaP) profile a key factor for resource-limited missions. To meet this need, we propose an integrated, scalable, multichannel, spectrometer baseband processing unit that accepts multiple down-converted RF signals from several independent front-end receivers and processes them to obtain multiple radiance spectra simultaneously with minimum amounts of power. We present the formulated requirements for the low SWaP scalable spectrometer back-end, followed by the derived architecture and design. A brief discussion of parts selection is followed by presentation of a prototype hardware/firmware solution and test results. A concluding discussion of alternative uses for the multi-channel integrated base-band receiver design are presented as well.