Acquiring pulse a priori information for chirp transform spectrometer systems through phase error measurements

Abstract With the rapid advancement in deep-space exploration, back-end systems such as chirp transform spectrometers (CTSs) must be equipped with larger bandwidths, higher frequency resolutions, and enhanced sensitivities. Phase errors in chirp signals distort pulse compression waveforms, significantly affecting CTS system performance. To correct the distorted pulses, we acquire a priori information about the pulse waveform by measuring the phase errors in the CTS system. This paper measures and analyzes phase errors in the expander and compressor signals of a 1 GHz bandwidth CTS system. We discuss the impact of these phase errors on pulse waveforms, system frequency resolution, sensitivity, and other critical performance parameters. Additionally, we plot the in-band phase error curves for the system. By utilizing these phase error curves, we can determine the phase error for any input frequency, thereby providing valuable prior information for pulse compression waveform correction. This approach is crucial for guiding subsequent error optimization and compensation in the CTS system.