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Signal Phase Shift Analysis

IP.com Disclosure Number: IPCOM000082249D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Leavitt, RA: AUTHOR [+2]

Abstract

Phase shifts occurring in a received signal may be quantified and analyzed without using the originally transmitted signal.

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Signal Phase Shift Analysis

Phase shifts occurring in a received signal may be quantified and analyzed without using the originally transmitted signal.

Phase encoded (PE) digital data 1 is originally transmitted as corresponding frequency-modulated signals 2. The received signals 3 exhibit phase shifts due to processing circuit characteristics. It is useful to determine the amount of phase shift of the received signal 3 relative to the transmitted signal 2 and analyze the amount of phase shift as a function of digital data transition patterns (identified as -11, 11, etc.), when only the received signal 3 is available.

The received signal 3 is sampled n times per transition (5<n<15) and a reconstructed received signal 4 is established via curve fitting techniques. The time t(r), at which each peak value of this reconstructed signal occurs, establishes the transition timing for construction of a detected signal 5.

The time between transitions of signal 5 is established as either one of two clock periods via a program, which tracks signal 5 with a variable-frequency clock (simulating the processing circuits).

Then the total time period T of the test sample is divided by the total number of clock periods to establish a reference clock period. This reference clock period will differ from the original recording clock period by an amount determined by the processing circuits.

The reference clock period T multiplied by the number of accumulated clock periods establishes...