A SAW analog correlator using the chirp transform
Abstract
Two programmable analog signal processors for use in modern radar and communications systems have been developed utilizing a chirp transform algorithm to perform the Fourier transform operation. Three operations are used to implement the algorithm for the Fourier transformation of the two input signals: (1) multiplication of the input signal by a linearly sweeping local oscillator (SLO), (2) convolution of the resulting signal through a linear FM dispersive filter (surface acoustic wave chirp filter), and (3) a final multiplication with an SLO. One of the chirp transform correlators (CTC) provides asynchronous operation, which allows correlation of incoming signals independent of their time of arrival, and also cross-correlates the signals having nonuniform spectra, such as a nonlinear FM, PSK, and gated CW waveforms. The CTCs are notable for their large time-bandwidth product and adaptability for any waveform within the processor's time and bandwidth windows, and they also provide low-power, real-time signal processing utilizing available technology.
- Publication:
-
Microwave Journal
- Pub Date:
- July 1982
- Bibcode:
- 1982MiJo...25...97E
- Keywords:
-
- Analog Circuits;
- Chirp Signals;
- Correlators;
- Fourier Transformation;
- Signal Processing;
- Surface Acoustic Wave Devices;
- Bandwidth;
- Convolution Integrals;
- Cross Correlation;
- Microwave Circuits;
- Real Time Operation;
- Spectral Correlation;
- Electronics and Electrical Engineering