The wideband receiving system will generate a large number of real-time astronomical signals, but the signal preprocessing, transmission, processing and storage have become urgent issues in the operation of large radio observation equipment.

Channelization technology uses decomposes wideband signal into several adjacent sub-bands and then realizes signal processing separately. It can effectively reduce the system pressure and improve the efficiency of wideband signal processing. And the oversampled polyphase filter bank technologies can solve the problems of spectral leakage, sub-band edge signal attenuation and aliasing in the traditional channelization.

Recently, Dr. ZHANG Meng from Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences, under the guidance of Dr. ZHANG Hailong, designed an 2× oversampled polyphase filter bank to realize channelization and solve the problems of sub-bands edge signal attenuation, spectral leakage, and aliasing encountered in wideband signal channelization.

The study was published in Research in Astronomy and Astrophysics.

Using the wideband baseband data generated by the Collaboration for Astronomy Signal processing and electronics research Parkes Swinburne Recorder (CASPSR), the researchers implemented sub-band division and multi-band output. In addition, they confirmed that a flatter overall passband was obtained by removing the redundant data at the edge of each sub-band in oversampling channelization.

The researchers channelized the 400MHz baseband data of J0437-4715, and compared the pulse profile obtained by direct processing of the original baseband data with the pulse profile obtained after the channelization and recombination. The results verified that the correctness of the oversampled channelization algorithm, the phase and amplitude information of the pulse profiles are consistent, and the comparison is shown in figure 1.

According to the researchers, applications of the oversampled polyphase filter bank related technologies can effectively improve the quality of radio astronomical observation data.