Browse Prior Art Database

Data-Aded Energy Drop Detector Arrangement

IP.com Disclosure Number: IPCOM000099601D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Maddens, F: AUTHOR

Abstract

The arrangement of the invention uses a conventional line down detector. It is based on the energy drop detection when the signal is stopped at the transmitter end. To take account of the mechanism accuracy, a special one sequence is added before terminating the session (when RTS drops) to prevent having additional extra bits or the loss of the last bits. The purpose of the new arrangement is to increase the probability of stopping the receiver in the one data sequence without increasing the one data sequence duration.

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This is the abbreviated version, containing approximately 54% of the total text.

Data-Aded Energy Drop Detector Arrangement

       The arrangement of the invention uses a conventional line
down detector. It is based on the energy drop detection when the
signal is stopped at the transmitter end. To take account of the
mechanism accuracy, a special one sequence is added before
terminating the session (when RTS drops) to prevent having additional
extra bits or the loss of the last bits. The purpose of the new
arrangement is to increase the probability of stopping the receiver
in the one data sequence without increasing the one data sequence
duration.

      At the receiver end, when the end of transmission is received,
the analog signal being random and corrupted by line impairments,
such as noise, non-linear distortions (phase jitter, etc.), the
energy drop can be detected so that the last transmitted data are
lost (e.g. the last 3 or 4 bauds). To have better protection, the one
data sequence length could be increased, but this increase would
downgrade the modem performances. A better approach is a data-aided
end-detector correlating what was the last detected data when the
energy drop has been detected.

      In reference to the figure, when the energy drops, the carrier
detector (CD) goes down, and the received data line on the V24
interface must be set IDLE (one). The improvement will be to take
account of how many consecutive one bits have been detected. If this
number is greater than a given value (e.g., 4), then the CD line will
be for...