Browse Prior Art Database

Receiver Synchronization for Data Transmission

IP.com Disclosure Number: IPCOM000091429D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Nussbaumer, H: AUTHOR [+2]

Abstract

In many data transmission devices, the receiver clock is set on the received message or on a particular signal of this message. Very often, the synchronizing signals are generated when the signal corresponding to the message takes a determined value or has a determined variation. These aspects of the signal can occur not only at the synchronization instants but, randomly, at other instants. The correct instants are selected from complementary features of the message signals.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 69% of the total text.

Page 1 of 2

Receiver Synchronization for Data Transmission

In many data transmission devices, the receiver clock is set on the received message or on a particular signal of this message. Very often, the synchronizing signals are generated when the signal corresponding to the message takes a determined value or has a determined variation. These aspects of the signal can occur not only at the synchronization instants but, randomly, at other instants. The correct instants are selected from complementary features of the message signals.

When the message presents data zones and nonsignificant zones appearing periodically with a period T, it is possible at an instant t to demodulate the received signal by the signal received at the instant t - T and phase shifted by Pi/4. The signal SF obtained, after filtering to eliminate the harmonics formed by the demodulation, returns a signal having a level variation when received data changes from one value to the other. If the receiver clock is well synchronized, the transition of SF occurs in a predetermined position with reference to the clock signals. If this is not the case, the clock must be resynchronized.

At demondulator M, the signal entering at IN is demodulated by the corresponding signal at instants t-T delivered through the delay line T and phase shifted by Pi/4, the low-pass filter LPF delivering the signal SF. This signal is squared in SQ and its transition starts one of the two single-shots S-S1 and S- S2, thus generating co...