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Time Interval Detection Circuit

IP.com Disclosure Number: IPCOM000092740D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Thompson, BG: AUTHOR

Abstract

The circuit detects if the time interval between successive pulses is greater or less than a prescribed interval. The circuit employs two delay circuits and two latch circuits. In the delay circuits the output turns on as the input turns off. After a fixed time interval the output turns off. If the input is turned on again before the delay circuit times out, the output remains on and restarts its time out when the input turns off.

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Time Interval Detection Circuit

The circuit detects if the time interval between successive pulses is greater or less than a prescribed interval. The circuit employs two delay circuits and two latch circuits. In the delay circuits the output turns on as the input turns off. After a fixed time interval the output turns off. If the input is turned on again before the delay circuit times out, the output remains on and restarts its time out when the input turns off.

Delay 1 is used to generate a short pulse of fixed duration at the beginning of the Input 1 signal. This short pulse is Input 2 which sets Delay 2. Latches 4 and 5 complete the circuit. The circuit detects the time interval variation in phase with the change in Input 1.

Latches 4 and 5 are priority devices in which the Set input has priority over the Reset. When Delay 2 times out Delay 2 sets L4. Input 1 is low at this time and tries to reset L4, but because of the Set priority it is ineffective. When Input 1 goes high, L4 latches and. remains on until Input 1 goes low again. If Input 1 rises before Delay 2 times out, L4 does not receive another Set pulse and remains off until Delay 2 times out. L5 is set by L4 which, if on, overrides the reset from Input 2. If Delay 2 does not time out, L4 is reset and Input 2 resets L5. The latter then indicates that the time interval is greater than Delay 1 + Delay 2.

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