Abstract: A retrodirective interrogation responsive system wherein a responder, illuminated by an interrogator, receives an interrogation signal, modulates information onto the interrogation signal, and retransmits the encoded interrogation signal back in the direction of arrival of the collected interrogation signal. The responder uses a Van Atta array antenna and is capable of responding to an interrogator signal incident over a wide solid angle of arrival while retrodirectively retransmitting without amplification substantially all of the collected signal within a narrow solid angle. The responder may be implemented using monolithic microwave integrated circuit technology (MMIC), thus being suitable for high volume production.

Abstract: The present invention is a system that performs code compression in stages where each stage includes two processing paths 36 and 38. The two paths allow bidirectional crossover cascade complementary code compression reducing the number processing stages to log.sub.2 N and reducing the number of processing by a factor of N/(2 log.sub.2 N) where N is the length of the code. Each path includes a delay provided by a delay unit 44 and each path arithmetically combines the data from its own path with data from the other path. The upper path 36 uses an adder 40 while the lower path uses an adder/substracter unit 42 which adds or subtracts depending on the phase of the transmitted complementary phase code. The delay provided in each stage increases in a binary progression with the delay of the last stage being N/2. A systolic processor 68 is the preferred embodiment although the invention could be implemented in a programmable digital signal processor.

Abstract: A synthesizer combines frequencies for multiple targets, accumulating the phase components separately and allowing the targets to change velocity separately. The amplitude of the simulated signal at the phase secified is generated using a method that combines coarse and fine angle components of the desired angle signal allowing small high speed memories to be used. A first ROM is addressed by high order bits of the phase component and a second ROM by the lower order bits. The outputs of the first and second ROM's are multiplied and then added to the output of the first ROM producing the amplitude of the desired phase. The system also allows the amplitude of the signal being synthesized to be modulated by multiplying the synthesized digital value by an amplitude modulator. The synthesized amplitudes for each frequency are combined. Digital zero order hold correction removes amplitude distortion from the output spectrum.

Abstract: A document transfer system for receiving a cluster of stacked documents within the first end of an output holder and, by using movable partitions, advancing the clusters to the second end of the output holder, thereby permitting a next document cluster to be received within the output holder at the first end. A document cluster at the second end of the output holder is then, using extendable and retractable gates, transferred from the output holder to a separate holder for further processing.

Abstract: A method for increasing the throughput of a multiple pass document sorting device that sorts documents into a plurality of output holders by automatically displacing the sorted documents within the receiving areas of each output holder into recirculation holders. The recirculation holders are then sequentially aligned with the input holder and the associated document cluster is transferred to the input holder. In this manner a next sorting pass may be initiated, using documents from the recirculation holders, with documents being sorted into the available output holders.

Abstract: A method and apparatus for increasing the throughput of a multiple pass document sorting device that sorts documents into a plurality of output holders by automatically displacing the sorted documents within the receiving areas of each output holder into a transitional area to make the receiving areas available. In this manner a next sorting pass may be initiated, using documents from the transitional area from the output holders, without the need to empty all of the output holders before a sorting pass can be initiated.