A circuit for allowing one microwave oscillator to be time shared between multiple incoming radar pulse trains for electronic countermeasure jamming purposes. Each pulse train is composed of pulses of radio frequency energy at a particular carrier frequency which is generally different from the carrier frequencies of other pulse trains. The circuit allows the microwave oscillator to be time shared on a pulse by pulse basis between all of the incoming radar pulse trains. When an individual pulse train first enters the circuit, the circuit searches for the carrier frequency of the pulse train, and after lock-on digitally memorizes the carrier frequency for use in jamming as succeeding pulses are received in that pulse train. As each pulse in the pulse train is received, the circuit compares the frequency in memory with the carrier frequency of the received pulse. During the search period the circuit first goes through a coarse tune search sequence and then a fine tune search sequence. During the coarse tune search sequence the two frequencies are compared and if the two frequencies are greater than 10 megahertz (MHZ) apart, the circuit adds 10 MHZ to the frequency in memory. In this manner, the frequency stored in memory is stepped by 10 MHZ with each succeeding pulse until the frequency in memory comes to within 10 MHZ of a currently received pulse in the pulse train. At that point, the circuit enters a fine tune search sequence, and steps the frequency in memory by one MHZ increments until the frequency in memory is within one MHZ of a currently received pulse in that pulse train. Upon receipt of succeeding pulses in the pulse train the correctly memorized carrier frequency drives the microwave oscillator, the output of which is utilized for electronic countermeasure jamming purposes. If the carrier frequency of a pulse train is slewing, the circuit has the ability to track the slewed frequency without going into a search mode provided the slew rate is less than .+-. 10 MHZ per pulse.
An apparatus for measuring the rate of change of voltage and the polarity of a pulse having a two input terminal differential amplifier with a delay line connected to one of the input terminals.
A system for selectively storing parallel trains of digital information produced in a converter from a plurality of received signals, comprises a plurality of stores arranged in parallel storing channels, a plurality of comparators connected between a pair of stores and between corresponding outputs of the converter to ascertain coincidence between received and stored information, counting circuits for registering each match in respective comparators, and preference logic circuits for resetting all stores except the ones at which a match occurs.
An antenna system for a flying body for jamming radio/radar signal transmitting and receiving devices. The antenna system includes a receiver with a frequency discriminator, a transmitter with a variable frequency oscillator, a transmit/receive device for conducting signals to the receiver and for conducting the transmitter signal to the antennas, a switch for selectively or cyclically connecting the antennas to the receiver and transmitter, a time which enables the receiver device to receive signals from antennas during one complete cycle of the switch and which enables the transmitter during the subsequent transmit mode to furnish transmitter signals to selected antennas for at least one complete cycle of the switch and a memory in which frequency representations are stored so that each representation corresponds to a particular antenna via which signals were received.
The standard interface unit (SIU) is used with the AF-EWES Threat Radar Simulator which selects the best ECM (electronic countermeasure) techniques to counter threats such as surface-to-air missiles (SAM's) and anti-aircraft artillery (AAA). The SIU comprises three modules: (1) Serial Bidirectional Party Line (SBPL) Monitor (2) Acquisition Subsystem Interface Unit (ASSIU) and (3) Multiplex Terminal Unit (MTU). The SBPL Monitor accepts data in serial format and converts it to a parallel format for storage in one of two buffers. The data in storage is next sent to the ASSIU which also has a double buffer set-up for storage of data on a FIFO basis. The data is then transferred to the MTU for reformatting into MIL-STD-1553B, and shipped out serially.
A device for determining the frequency range and chirp rate of chirp radars or other sources of frequency-modulated signals includes a compressive receiver (16, 22, 24) for time-compressing single-frequency signals and a discriminator (26) for generating an output that represents the instantaneous frequency of the compressive-receiver output. For narrow-band signals, the frequency-modulated components in the output of the compressive receiver do not last long enough to cause a response from the discriminator (26). When the input of the compressive receiver is a chirp signal, on the other hand, the resultant compressive-receiver output lasts long enough to cause a discriminator response, and its time of occurrence and rate of frequency change are indications of the frequency range and chirp rate of the compressive-receiver input. The discriminator (26) accordingly generates an output whose slope is an indication of the chirp rate of the compressive-receiver input.
