Browse Prior Art Database

High Accuracy Time Meter

IP.com Disclosure Number: IPCOM000082020D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Millham, EH: AUTHOR

Abstract

Testing events for large-scale integrated semiconductor devices can be measured from 100 picoseconds to several milliseconds with +/-.0001% accuracy by the described time meter.

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High Accuracy Time Meter

Testing events for large-scale integrated semiconductor devices can be measured from 100 picoseconds to several milliseconds with +/-.0001% accuracy by the described time meter.

Figs. 1 and 2 show a typical time meter and controlling circuitry thereof for measuring time events within the limits and accuracy, set forth above. A start signal is provided to latches 2 and 7, the former in conjunction with an output signal from a free-running crystal-controlled oscillator 1 operating at 100 MHZ initiating a latch 3. The latch 7 initiates a time meter 10 shown in Fig. 1.

The latch 3 is set on the first positive half-cycle of the oscillator 1. The next half-cycle of the oscillator 1 and output from latch 3 initiates the latch 4, which, in turn, allows the next positive half-cycle of the oscillator to reset latch 3 and start counter 9.

With each positive half-cycle of oscillator 1, the counter advances 1 count corresponding to 10 nanosecond increments. The first advance pulse to the counter 9 together with a reset pulse resets the latch 7, 1 count corresponding to 10 nanosecond increments. The first advance pulse to the counter 9 together with a reset pulse resets the latch 7, causing the time meter 10 to stop and hold the analog voltage level, corresponding to the time when the start event occurred and the counter 9 was initiated.

Subsequently a stop event initiates latch 8 which starts time meter 11. After a 10 nanosecond delay latch 2 is reset, allowing the first positive half-cycle of oscillator 1 to reset latch 5. The 10 nanosecond delay is required only for those instances where t...