[PCG21-P04] Small Plasma Waveform Capture Receiver on the analog-digital mixed chip
Keywords:Small Plasma Waveform Capture Receiver, ASIC (Application Specific Integrated Circuit)
In order to reduce the required resource for plasma wave receivers, our research group has been attempting to miniaturize plasma wave receivers using ASIC (Application Specific Integrated Circuit) technology.
In the present paper, we focus on the development of a small waveform capture receiver based on an analog-digital mixed chip. The waveform capture receiver is a receiver to acquire waveform data of plasma waves sampled directly. The amount of original waveform data is large, so it is difficult to send them to a ground station without data compression. The onboard data compression is realized by a digital part of a plasma wave receiver. On the part of the digital processing, we succeeded in implementing the data compression logic on the FPGA in Kanazawa University. By using the logic in the FPGA, our research introduces the data compression logic onto an analog-digital hybrid chip. The target of our research is to achieve the ultimate miniaturization by putting both analog part and digital part which are in the waveform capture type receiver into one chip. In this presentation, the digital filters used in the waveform compression are implemented on the ASIC chip and its operation verification was carried out.
On the other hand, we added the additional function to the analog part of the waveform receiver chip. In addition to the dipole measurement taking the differential of the dipole antenna, there is an interferometry mode in which the two antennas of the dipole antenna are monopole antennas. By using the interferometry mode, we can identify the phase velocity of the plasma wave, which is a necessary observation item in next scientific satellite missions. However, since the differential is not taken in the interferometry mode, it is weak against external noise. Also, crosstalk between different channels should be examined. The chip which was made this time has two circuits, a circuit which performs dipole measurement and monopole measurement at the same time, and a circuit which switches between dipole measurement and monopole measurement. We show the performance in each circuit on the chip and results of immunities against external noises. We also check the linearity of the switch that alternatives the circuits for the dipole mode and monopole mode.
In this presentation, we present the details of the design of the circuit mounted on the chip made this time and its operation verification result. Moreover, we explain the results of its operation verification, and guidelines for further development as a more advanced waveform capture receiver in the future.