Empfangseinrichtung in einer Radaranlage

Korrelator und Detektor für die Videosignale einer Radaranlage

Multilevel Digital Skimmer

... 1,156,896. AID converters. HUGHES AIRCRAFT CO. 15 Feb., 1968 [23 Feb., 1967], No. 7559/68. Heading G4H. [Also in Division H4] In a radar receiving system the peak level of video returns is detected during each range bin, the receiver gain is determined at selected instants to afford a reference voltage related to the receiver gain and detectors are each responsive to the peak magnitude, the reference voltage and an adjustable threshold (" skim ") level, each detector providing an output signal when the peak video level exceeds the skim level by a preselected magnitude which is different for each detector. In the embodiment the receiver is logarithmic and the skim level is set by known means to maintain a constant false alarm rate related to " hits " 3dB above R.M.S. noise. The peak video level detector is a box-car and the detectors D2 . . . D7 include resistors R2 ... R7, operational amplifiers 30, inverters 33 and bi-stables 32. The outputs of detector D2 . . . D7 may be applied to a ...

Improvements in Pulse Radar

... 1,167,671. Pulse radar. HUGHES AIRCRAFT CO. 20 Feb., 1968, No. 8283/68. Heading H4D. In a pulse radar with range sweeps effected sequentially in elevation at each azimuth position, the video returns for each range interval in each range sweep are amplitudequantized and the quantized signals are correlated over several elevations to provide a target detection signal. In the embodiment the video amplitude quantization covers eight steps which are three-bit coded and "hits are enumerated as e.g. 7-hit and the acceptable hit patterns are as shown in Fig. 3 where each three-by-three matrix (" window ") represents adjacent azimuth (columns) and elevation (rows) positions for a particular range interval (see also Fig. 2), a moving window technique is incorporated. Detailed embodiment. Figs. 2, 4.-In the embodiment there are ten range sweeps sequentially in elevation and each range sweep has 400 range intervals. A memory 25, Fig. 4, has a capacity of 4000 words each of eighteen bits and the capacity ...

IMPROVEMENTS RELATING TO PULSE RADAR

... 1,220,704. Pulse radar. HUGHES AIRORAPT CO. 19 June, 1968 [19 June, 1967], No. 29152/68. Heading H4D. In a radar receiver the video returns are amplitude-quantized, into a multilevel code consisting of several bits, for each range "bin" interval, and are utilized to update the count in a multibit counter associated with each range bin; the count for each radar sweep, as well as the counts in preceding sweeps, and/or adjacent channels in a stacked beam radar, are used to generate leading and trailing edge signals for target azimuth detection. In the embodiment a 3-bit code is utilized in the quantization of amplitude e.g., the code 001, representing an amplitude of one, corresponds to a peak video level X of between 2À8 dB and 5À8 dB above r.m.s. noise: the 3-bit code utilized is designed to reduce false alarms due to noise. A threshold count of eight is selected for leading edge detection of a target and when the leading edge is detected the counter logic is modified, the counter is reset ...