Fig. 7
From: OCTAD-S: digital fast Fourier transform spectrometers by FPGA
(Top) Solar radio type II burst observed by OCTAD-S (2G64K) on November 4, 2015. (Middle) Zoomed up image of one burst element indicated by the white rectangle in the top panel (observed between 3:26–27 UT). (Bottom) The solar radio burst observed by HiRAS at the same time and frequency ranges as the middle panel. Color of the radio dynamic spectra indicates the radio enhancement in dB from the background (BG). Horizontal lines in the radio dynamic spectra are artificial radio frequency interferences (RFIs)