COMMUNICATION RECEIVER

Abstract

Disclosed is a communication receiver for use in a burst communication system. A typical system is composed of a transponder and an interrogator. The transponder receiver and interrogator receiver operate in an asynchronous communication mode. The incoming coded signal is down converted to an i.f. frequency compatible with surface acoustic wave (SAW) convolvers. The i.f. signal is then divided between two SAW convolvers, each having a convolution interval of two times the message symbol length (2T). Reference signals having a bit length of T provided to each of the two convolvers are time reversed to the coded spread sequences and applied to each of the convolvers at a 50% duty cycle. Each of the convolver outputs are processed through log video detection circuits to reduce the dynamic range followed by peak detecting and stretching to reduce the pulse bandwidth. The outputs from each peak detection and stretching circuitry are coupled to a sample-and-hold circuit which are in turn divided such that one path is to synchronization and interrogation sidelobe suppression (also referred to as sidelobe inhibit, ISLI or control signal) matched filters designed to look for the particular symbol sequences between the two convolver channels characteristic of the preamble and ISLI signals. The synchronization signal and the sidelobe suppression signal are used in order to determine if valid synchronization has been detected by the receiver and if the receiver is in a desired portion of the interrogator radiation pattern; if so, then a timing or address signal clocks into a memory the remaining portion of the message which contains the data.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1DONALD W. MELLON

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