Communication receiver

A communications receiver for receiving overlapping multibit coded message input l.f. signals from at least one transmitter, said message comprised of a preamble and data signal wherein one bit is of length T, comprising

• a convolver having a convolution interval of 2T, and an input port connected to receive said multibit i.f. coded message, a reference port connected to receive a reference signal having a bit length of T and a 50% duty cycle and an output port producing a full correlated i.f. bit amplitude signal when said reference signal and a bit of information from said coded input message exactly correlate and overlap in said convolver,
• a signal processing means coupled to said output port for converting the full correlated i.f. signal to a video signal,
• preamble detection circuitry coupled to said signal processing means for detecting the time arrival of each preamble to provide synchronization and generation of a clock signal for each such preamble, and
• data processing and storage means coupled to said signal processing means and said preamble detection circuitry having a plurality of storage locations related to the number of overlapping messages such that the data signals from said signal processing means is entered into each of said storage locations as clock signals are generated by said preamble detection circuitry and provided to said storage locations.

A receiver system for receiving overlapping coded multibit message input signals from at least one transmitter, said input signals comprising a synchronization and data information on its sum pattern and a control signal on its difference pattern and having a bit time period equal to T, comprising

• (a) at least two receiver channels A and B,
• (1) channel A comprising a first convolver having a convolution interval of 2T and having an input, reference and output port, said input port connected to receive an i.f. representation of the coded multibit signals, the reference port coupled to receive a reference signal A having a bit length of T and a 50% duty cycle, such that said first convolver produces at its output port an i.f. amplitude correlation of said coded multibit input signal when said reference signal A and a bit of information from said coded input message exactly correlate and coincide in said first convolver,
• (2) first signal processing means coupled to said output port for converting such correlated i.f. signal to a first video signal and producing its maximum amplitude during predetermined time intervals to form the output signal of channel A,
• (3) channel B comprising a second convolver also having a convolution interval of 2T and having an input, reference and output port, said input port connected to receive the same signal as the input port of said first convolver, the reference port coupled to a receive reference signal B, also having a bit length of T and a 50% duty cycle, such that said second convolver produces at its output port an i.f. amplitude correlation of said coded multibit input signal when said reference signal B and a bit of information from said coded input message exactly correlate and coincide in said second convolver,
• (4) second signal processing means coupled to receive said output port for converting such correlated i.f. signal to a second video signal and producing its maximum amplitude during predetermined time intervals to form the output signal of channel B,
• (b) processor means coupled to receive the output signals of channels A and B for detecting, storing and de-interleaving said overlapping messages, and including a plurality of memory locations, and
• (c) synchronization detection circuitry coupled to receive the output signals of channels A and B for identifying synchronization of said overlapping messages to establish time of arrival of said overlapping coded multibit message input signals and produce signals selectively to said plurality of memory locations to transfer the data bits into selected memory locations.

An IFF system comprising

• (a) at least one interrogator comprising an interrogator transmitter and receiver, said interrogator transmitter transmitting a multibit coded message including synchronization and data information on the sum pattern and a control signal on the difference pattern, each bit being of length T,
• (b) at least one transponder comprising a transponder transmitter and receiver, said transponder receiver detecting and validating receipt of said message and control signal and said transponder transmitter transmitting a unique message in response thereto which is detected by said interrogator receiver,
• (c) said interrogator and transponder receivers each comprising
• (1) at least two receiver channels A and B,
• channel A comprising a first convolver having a convolution interval of 2T and having an input, reference and output port, said input port connected to receive an i.f. representation of the coded multibit signals, the reference port coupled to receive a reference signal A having a bit length of T and a 50% duty cycle, such that said first convolver produces at its output port an i.f. amplitude correlation of said coded multibit input signal when said reference signal A and a bit of information from said coded input message exactly correlate and coincide in said first convolver,
• first signal processing means coupled to said output port for converting such correlated i.f. signal to a first video signal and producing its maximum amplitude during predetermined time intervals to form the output signal of channel A,
• channel B comprising a second convolver also having a convolution interval of 2T and having an input, reference and output port, said input port connected to receive the same signal as the input port of said first convolver, the reference port coupled to receive a reference signal B, also having a bit length of T and a 50% duty cycle, such that said second convolver produces at its output port an i.f. amplitude correlation of said coded multibit input signal when said reference signal B and a bit of information from said coded input message exactly correlate and coincide in said second convolver,
• second signal processing means couple to said output port for converting such correlated i.f. signal to a second video signal and producing its maximum amplitude during predetermined time intervals to form the output signal of channel B.
• (2) processor means coupled to receive the output signals of channels A and B for detecting, storing and de-interleaving said overlapping messages, and including a plurality of memory locations, and
• (3) synchronization detection circuitry coupled to receive the output signals of channels A and B for detecting synchronization of said overlapping messages to establish time of arrival of said overlapping coded multibit message input signals and produce signals selectively to said plurality of memory locations to transfer the data bits into selected memory locations.