Abstract: A modular solid-state radar transmitter apparatus for producing waveforms whose amplitude may be varied over time. The transmitter achieves pulse modulation on either an intrapulse or pulse to pulse basis, while at the same time reducing stress on individual solid-state modules. Intrapulse modulation and pulse to pulse modulation can be produced with the disclosed modular solid-state transmitter because the number of modules and the sequence in which they are activated is selectable. These selections provide the various desired levels of transmitted power and thus effectively achieve modulation. In order to achieve this intrapulse modulation, a variable combiner is introduced whose coupling factor is coordinated with the module activations. In one embodiment, variable combining is accomplished by the use of RF switching logic for combining pairs of signals in parallel. In this case, RF switches are programmed to act as a conventional combiner when all modules are active.

Abstract: The maximum amplitude of an input signal (IN) is compressed or reduced to a smaller value suitable for operation on the compressed signal (OUT) by a downstream signal processing stage (16) having insufficient dynamic range, ratio of maximum amplitude to root-mean-square (RMS) noise, to accommodate the original input signal (IN). The input signal (IN) is digitally sampled with coarse resolution to generate a correction signal (44) having a waveform which approximates only the large signal components (24) of the input signal (IN). Where the input signal (IN) consists of recurring received radar pulses, the large signals (24) represent clutter. The amplitude of the correction signal (44) is lower than and increases as a predetermined function of the amplitude of the input signal (IN), and is subtracted from the input signal (IN) so that the large signal components (24) are reduced whereas the small signal components (26), which represent desired target information, retain their original amplitude.

Abstract: Electronic priority map storage and control for prioritizing radar detections for fire control or monitoring purposes relative to batteries of mortars or artillery or other projectile sources. Use of a priority map to increase probability of location of at least one weapon in each battery is desired. The theory is based upon the premise that all guns in a battery are firing at the same target and, consequently, all projectiles from a battery will be detected within a relatively small area. By distributing track initiations over a large area of detection, the probability of tracking projectiles from all batteries is increased. The use of the priority map to accomplish this function is made in order to save time in a general purpose data processing computer employed additionally for other functions. A group of priority map cells are combined to form a track initiation cell. That is, a second map is formed with coarser granularity for the purpose of controlling the priority of track initiations.

Abstract: An adaptive, fail-soft digital filterbank for digitized Doppler-modulated video signals. A plurality of modules are controlled by the impulse filter weighting technique to each respond to a set of discrete Doppler frequencies. A built-in test feature is included, the module inputs being multiplexed between system digitized video and synthetic signals to continuously confirm proper operation. Module failures are recognized by the control (programming) circuitry and spare modules can be activated. Control and communications link circuitry is constructed with multiple redundancy.

Abstract: A radar system is provided with first and second moving target indicator (MTI) systems. The first MTI system generally works better against ground clutter than against sky clutter. The second MTI system works well against sky clutter but generally requires a greater number of radar return echoes to discern targets in the sky clutter. A correlation estimation circuit is employed to calculate the correlation of clutter-like return echoes not suppressed by the first MTI system. If the return echoes are sufficiently correlated, the second MTI system is invoked against the clutter. If the return echoes are less well correlated, on the other hand, then electronic counter-counter measure systems may be invoked.

Abstract: A system for quantitative measurement of pulse circuit stability parameters, such as pulse time, amplitude and duration, and frequency or phase of an RF source. The device is a video instrument and the input pulse is ordinarily a demodulated RF pulse from a system to be evaluated, and includes an analog conditioning section and a digital processing section allowing for an analog indication of RMS "jitter." Means are provided for sampling and converting all parameter variations to amplitude variations and for quantizing them to digital form. Digital signal processing such as FFT, MTI Cancelling circuits, etc., are provided, after which there is digital-to-analog conversion and RMS detection and indication. Thus the measurement effected may be thought of as based on the MTI residue resulting from transmitter pulse instabilities of the type aforementioned.