Design Of High-speed Broadband Spectrometer For Radio Astronomy

Spectrometers for radio astronomy have played an important role in observations of pulsars, coronal mass ejections, galaxy spectrum redshift and other studies, and have aslo provided a powerful tool for exploring unknown astral as well as searching for extraterrestrial civilization. The growing demands for astronomical observations put forward higher requirements for spectrometers including wider bandwidth, higher frequency resolution, higher time resolution, real-time processing and continuously recording, and therefore the research of high-speed broadband real-time spectrometer has important theoretical significance and application value.This paper analyzes the development status of spectrometers for radio astronomy, combined with the actual needs of radio astronomy observations, and then completes the design and implementation of the spectrometer for radio astronomy, which is high-speed, broadband, high-frequency-resolution, high-time-resolution, real-time processing and continuously recording. The hardware is based on the software defined radio receiver, composed of ADC, FPGA and ARM board. FPGA design includes data input interface module, Fourier transform module, Bartlett periodogram module, ARM control module and gigabit ethernet interface module. The data input interface module uses IDDR technology to devides the 2.4 GSps signal to 8 channels 300 MSps data, and uses IDELAY technology to compensate the phase delay caused by routing; Fourier transform module adopts the high-speed parallel algorithm of complex FFT to complete 32K-channel Fourier transform; Bartlett periodogram module calculates the power spectrum and finishes the accumulation and gain control operation according to user setting; ARM control module completes the initialization, parameter configuration and other work through the GPIO interface and AHB bus; gigabit ethernet module sends the spectrum data through GMII interface using "Request-Confirmation" handshake technology.The function and performance of spectrometer for radio astronomy is tested after implementation, the results show that the design is good to complete the spectrum analysis work for astronomical observations, and meets the design requirements.