Theoretical assessment of the use of pulse compression in a panoramic receiver

The paper presents a theoretical investigation of the application of the pulse-compression technique to a panoramic superheterodyne receiver. The sensitivity and resolution of such a system have been calculated and compared with those of a receiver without compression. Receivers having square-law or linear detectors, with both rectangular and Gaussian i.f. responses, have been considered. For the receiver without compression, the calculated sensitivity is that of the tangential setting; for the receiver with compression a similar calculation is made, based on the peak power of the compressed pulse. For a given receiver bandwidth, B1, and a sweep rate, R, the sensitivity improvement has a theoretical upper limit of approximately B21/R. Practical limitations to the magnitude of the increase are, however, set by the ability to design and construct suitable, dispersive delay networks operating over a wide frequency band, by unintentional variations in the sweep rate and by the possible difficulty of maintaining a good noise factor in a very wideband receiver where the i.f. extends to a very high frequency. In practice, improvements in sensitivity of up to 20dB should be possible. Information is also given for the design of a panoramic receiver without pulse compression.