<title>Surface Acoustic Wave Chirp Transform Techniques For Analog Signal Processing</title>

Abstract

Recent improvements in broadband, large time-bandwidth product surface acoustic wave (SAW) chirp filters have led to significant advances in the implementation of the Chirp Transform algorithm for analog signal processing. This paper concentrates on real-time Fourier transformation techniques for performing broadband spectral analysis and correlation using SAW chirp transformation. First, the fundamentals of the SAW chirp filter and the Chirp Transform algorithm are reviewed. Next, chirp transform system architectures are discussed, including the relationship between SAW filter de-sign and signal processor bandwidth, resolution and signal to noise ratio. Performance data is then presented for a new radar pulse-compression processor* which utilizes the Chirp Transform and incorporates state-of-the-art SAW chirp filters to perform cross-correlation between large time-bandwidth product waveforms. This "programmable" correlator is compatible with arbitrarily coded signals up to 60 psec long, with up to 60 MHz bandwidth. Finally, the SAW chirp transform is compared with other techniques for performing Fourier transformation, and specific applications of this technology for spectral analysis and correlation are discussed.