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US 4,306,237 AGranted
Pulsed solid state device having a preheat circuit to improve pulse shape and chirp
AssigneeThe Bendix Corporation
InventorCarl P. Tresselt
Life of this patent
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AssigneeThe Bendix Corporation
InventorCarl P. Tresselt
Estimating the term…
A timing circuit (20, 22, 24) for use with a pulsed solid state radar generates signals which are applied to a pulse forming circuit (33) to provide preheat and immediately subsequent thereto current drive pulses applied to IMPATT diodes which in response thereto generate RF signal pulses (10, 12) having reduced chirp and level variations. The pulses are formed by transistors (70, 74) which are rendered conductive when their current return paths (28, 38) are established through resistors (34, 44) whose values determine the levels of the preheat and drive pulses. The duration of the preheat pulse is made responsive to ambient temperatures by using a negative-temperature-coefficient thermistor (86) as the time determining element of the timing circuit. The level of the preheat pulse is made responsive to ambient temperature by using positive-temperature-coefficient silicon thermistors (34) in the above mentioned current return path.
A pulsed radar system having solid state elements responsive to drive pulses for generating RF signal pulses, the drive pulse interpulse period being used to receive radar return echoes from targets illuminated by said RF signal pulses, the time of arrival of a particular radar return echo at the radar system after a particular RF signal pulse being a measure of range to the target producing said particular echo, characterized by means for generating and applying preheat pulses to at least some of said solid state elements during the drive pulse interpulse period and including level attenuation means for maintaining the level of said preheat pulses below the level of said drive pulses.
A pulsed radar system which periodically generates and transmits RF signal pulses and receives radar return echoes from targets illuminated by said RF signal pulses wherein the elapsed time from the transmission of a particular RF signal pulse to the receipt of a radar return echo from a particular target illuminated by said particular RF signal pulse is a measure of range to said particular target, and wherein said radar system has a maximum range of interest, and wherein said radar system includes means having IMPATT diodes responsive to current drive pulses for processing said RF signal pulses, comprising:
The pulsed radar system of claim 12 wherein said means responsive to ambient temperature includes means for interrupting said preheat pulses above a predetermined ambient temperature.
Dependencies are inferred from the claim text.