Video processor for distance measuring equipment
First Claim
1. In a video processor for Distance Measuring Equipment, said Distance Measuring Equipment including means for transmitting interrogation signals to a responser station and means for receiving reply signals from said responser station, means for positioning a range gate to enable distance tracking of said reply signals comprising,a source of clock pulses,a memory counter for counting said clock pulses, said memory counter having a count capacity equal to the number of clock pulses which would occur during the time required for a signal to travel round trip between a Distance Measuring Equipment and a responser at maximum range of the Equipment,means actuated by a reply from the responser for starting count by said memory counter during a first interrogation-reply cycle of the Equipment;
- means for stopping count by said memory counter during said first interrogation-reply cycle at a time when a reply would have been received at maximum range between the Equipment and the responser;
means for restarting count by said memory counter during a second interrogation-reply cycle of the Equipment, said restarting means being actuated at a time prior to the time a reply would be received by the Equipment if located at zero range between the Equipment and the responser;
means for stopping and resetting said memory counter upon said memory counter'"'"'s reaching its full count capacity;
means actuated by said memory counter'"'"'s reaching full count for generating a fixed time period constituting a range gate; and
means for starting count by said memory counter a second time during said second interrogation-reply cycle whenever the reply is within said range gate.
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Abstract
A video processor for Distance Measuring Equipment in which all timing functions including fixed delays are performed by digital counters counting clock pulses from a highly stable source. Search and track operations are conducted by starting a memory counter by a reply from a responser and stopping the memory counter at a time corresponding to maximum range. On a succeeding interrogation cycle the memory counter is started prior to the time a reply at zero range would be received. In this cycle the memory counter begins count with the count it contained when stopped during the previous cycle; the memory counter counts until it reaches a number corresponding to maximum range, stops and initiates a range gate. A reply within the range gate causes the range gate to be repeated at the same time in the following interrogation cycle. A sufficient number of replies within the range gate cause tracking operation to begin. A velocity memory provides continuing tracking during temporary loss of reply signals.
11 Citations
15 Claims
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1. In a video processor for Distance Measuring Equipment, said Distance Measuring Equipment including means for transmitting interrogation signals to a responser station and means for receiving reply signals from said responser station, means for positioning a range gate to enable distance tracking of said reply signals comprising,
a source of clock pulses, a memory counter for counting said clock pulses, said memory counter having a count capacity equal to the number of clock pulses which would occur during the time required for a signal to travel round trip between a Distance Measuring Equipment and a responser at maximum range of the Equipment, means actuated by a reply from the responser for starting count by said memory counter during a first interrogation-reply cycle of the Equipment; -
means for stopping count by said memory counter during said first interrogation-reply cycle at a time when a reply would have been received at maximum range between the Equipment and the responser; means for restarting count by said memory counter during a second interrogation-reply cycle of the Equipment, said restarting means being actuated at a time prior to the time a reply would be received by the Equipment if located at zero range between the Equipment and the responser; means for stopping and resetting said memory counter upon said memory counter'"'"'s reaching its full count capacity; means actuated by said memory counter'"'"'s reaching full count for generating a fixed time period constituting a range gate; and means for starting count by said memory counter a second time during said second interrogation-reply cycle whenever the reply is within said range gate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A video processor for use in Distance Measuring Equipment to determine the time elapsing between initiation of an interrogation signal and the receipt and decoding of a reply signal, comprising,
a source of clock pulses; -
a first digital counter for accumulating said clock pulses and for generating at predetermined counts thereof; (a) an interrogation pulse pair signal; (b) a suppression pulse signal; and (c) a first end of count signal; a second digital counter enabled by said first end of count signal for accumulating a predetermined adjustable count of clock pulses and providing a second end of count signal; a third digital counter enabled by said second end of count signal for accumulating a predetermined count of said clock signals and providing (a) a relatively low selectable-count signal, and (b) a relatively high fixed-count signal;
said relatively high fixed-count signal constituting a first reference pulse;a fourth digital counter enabled by said first reference pulse for accumulating a count of said clock pulses corresponding to the maximum range at which the Distance Measuring Equipment is to be operated and providing a third end of count signal upon reaching said count corresponding to maximum range; means including a fifth digital counter for determining the spacing between pulse signals received by the Distance Measuring Equipment to establish reception of a pair of pulse signals having a predetermined spacing and for generating a delayed reply signal after a pair of pulses of said predetermined spacing has been received and after said fifth digital counter has counted a fixed number of said clock pulses beginning such count with the reception of the first pulse of said pair of predetermined spacing; distance tracking means including sixth and seventh digital counters, said sixth counter constituting a memory counter, said seventh counter constituting a range gate counter, during a first interrogation cycle consisting of the transmission and reception by the Distance Measuring Equipment of an interrogation pulse pair and a reply pulse pair, said memory counter beginning count of said clock pulses upon the appearance of said delayed reply signal and ending count upon the appearance of said third end of count signal, during a succeeding interrogation cycle said memory counter beginning count upon the appearance of said selectable count signal from said third counter and providing a fourth end of count signal upon reaching a count equal to the maximum range count of said fourth counter, said range gate counter beginning count of said clock pulses upon the appearance of said fourth end of count signal and providing a range gate center signal constituting a second reference pulse upon reaching a count intermediate of the counting capacity of said range gate counter, and means for restarting the count of said clock pulses by said memory counter during that same succeeding interrogation cycle either (a) upon the appearance of said range gate center signal, or (b) upon the appearance the first said delayed reply signal to occur after said range gate counter reaches its full count capacity. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification