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Clocking Circuit

IP.com Disclosure Number: IPCOM000094662D
Original Publication Date: 1965-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Chomicki, JS: AUTHOR

Abstract

The upper drawing shows a circuit for generating sampling pulses. The lower drawing shows pulses appearing at various points in this circuit under normal conditions. Since the circuit resynchronizes on pulse transitions, it is capable of generating a sampling pulse at the center of each data pulse even with up to +/- 50% time jitter.

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Clocking Circuit

The upper drawing shows a circuit for generating sampling pulses. The lower drawing shows pulses appearing at various points in this circuit under normal conditions. Since the circuit resynchronizes on pulse transitions, it is capable of generating a sampling pulse at the center of each data pulse even with up to +/- 50% time jitter.

In operation, the data is a latch 10 which sets for a 1 bit and resets for a 0 bit. From line A, an N-bit character starts with a 1 bit and ends with a 0 bit. Every transition in the input starts a single-shot 12 or 14. Single-shot 12 is fired for a 1 to 0 transition. Single-shot 14 is fired for a 0 to 1 transition. The duration of each of the single-shots is one half the normal bit. These two outputs are applied as two inputs to Or 16. The other input to Or 16 is the output from stop oscillator latch 18. Latch 18 is set on the first 0 to 1 transition and reset on the last bit of the character. Output E from Or 16 is applied as one input to And 20. An output from And 20 stops start-stop oscillator 22. This is of a type which stops on the fall of the synchronize input and remains stopped for the duration of this input. On the rise of the synchronize input, it restarts and free runs with the first output pulse occurring at the time of the rise in the synchronize input. The oscillator 12 output pulse is normally one quarter the bit, but can be more or less as long as it is less than the period of the one half bit period...