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Rohith Saradhy

Publications and source records attributed to Rohith Saradhy.

2 recordsLinked to original sources

A Sub-Picosecond Digital Clock Monitoring System

We describe a low-cost system designed to monitor wander in digital clocks with a precision of $\le$ 1 ps. With this system we have shown that it is possible to track phase variations at the sub-picosecond level by adding noise to a reference clock. As in many cases where a clock is part of a complex distribution network small changes in temperature and other effects can lead to small changes in the a clock's phase. As a further demonstration of the system, we have used it to measure the phase changes induced in optical signals in fibers.

physics.ins-det

A Sub-Picosecond Digitally-Controlled Phase Delay

The use of precision timing measurements will be a major tool at the HL-LHC, where it will be used to suppress pile-up and to search for long-lived particles. To control a reference clock with sub-picosecond accuracy, we have fabricated in the TSMC 65 nm process a digitally controlled phase shifter. It is composed of a chain of 66 cells, each with a digitally controlled planar wave guide with either a short or long delay. With this a reference clock's phase can be controlled to a precision of 200 fs with dynamic range of 12 ps.

physics.ins-det