Abstract: The precision microwave/millimeter wave modulated signal source is a relatively low cost, compact, highly accurate and stable signal source covering the 2 to 40 Gigahertz frequency range. The pulse width and amplitude level of the output signal can be changed on every pulse in the signal pulse train. Pulse width range is 5 nanoseconds to 1 millisecond. Pulse repetition intervals can be changed between each pulse set with usable range from 10 nanoseconds to 100 milliseconds. Interval parameters can be adjusted with 1 nanosecond resolutions with stabilities of +/−200 picoseconds. The highly accurate and versatile selection of signal parameters, along with its compact size, makes this design useful as an embedded built in test signal source. This built in signal source can be used for verification of system performance for many electronic warfare systems.

Abstract: The system and method for calibrating a signal detection threshold circuit is used in a radio frequency (RF) receiver, such as a in an early warning radar (EWR) system, in which a signal detection threshold circuit rejects signals below a predetermined threshold setting and prevents noise signals from causing false alarms. The system and method include setting an initial threshold setting and receiving noise signals in one or more channels. A threshold comparison circuit rejects noise signals below the threshold setting, and a pulse repetition frequency (PRF) detection circuit detects noise pulses above the threshold setting and determines the PRF. An automatic threshold determiner and setter determines whether the PRF has reached a predetermined frequency (e.g., 400 kHz) and lowers the threshold setting until the predetermined frequency is reached. When the predetermined frequency is reached the threshold setting is stored as a noise measurement.

Abstract: A multi-function radio frequency (RF) signal warning system detects different types of RF signals, such as radar signals, provided in various RF bands and provides an indication of the type of radar signal and the RF band. The system detects pulsed radar signals having different pulse repetition frequency (PRF) ranges as well as high duty cycle radar signals and continuous wave radar signals. The system includes a receiver processor that detects the radar signals, video amplifies the radar signals with baseline correction, and processes the radar signals to determine the type of radar signal, e.g., the RF band and PRF range. The receiver processor generates audio and visual control signals and transmits the control signals to one or more remote units. The remote units receive the audio control signals and generate an audible alarm.

Abstract: A ten db coupler receives an RF input signal and transmits an attenuated signal through a wideband/narrow band select switch to an RF amplifier. The signal is next processed through an RF amplitude detector. A comparator then receives the signal and generates a pulse in response to signals exceeding a predetermined threshold. A pulse stretcher then eliminates excessive pulses due to noise or other signal oscillations that exceeded the comparator's threshold. A circuit comprising a retriggerable monostable and an OR gate determine if the pulses received exceed a pulse repetition frequency threshold. A ripple counter than eliminates unwanted signals by resetting if a predetermined number is not reached in a specified time. A unique audio signal is then generated if the desired signal is detected. The output signal is audible even though the input signal is of a frequency above the normal hearing threshold. Also a visual signal is provided by a light emitting diode.

Abstract: A receiver selects and amplitude demodulates an RF signal from one of a pality of directional antennas. The demodulated signal is then delayed to put it in time synchronism with the same signal information from an omnidirectional antenna. A signal is then generated of the peak pulses of the demodulated signal when the pulses are in time synchronism with pulses from the omnidirectional antenna. A control indicator receives the peak pulses along with periscope bearing signals and ship's heading signals and gives an r,.THETA. display of the amplitude of the RF signal selected from the directional antenna at the periscope true bearing angle.