Browse Prior Art Database

Holter Tape Address Method for Start/Stop Scanning Without Loss of Data

IP.com Disclosure Number: IPCOM000051485D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Coker, CW: AUTHOR [+2]

Abstract

When a tape which contains EKG analog information is stopped during hig speed computer or manual processing, an undesirable loss of data or discontinuity in the EKG signal results when the tape is restarted. This article shows a method for resynchronizing the EKG signal on a restarted tape so that the EKG analysis computer program can continue processing the EKG waveform without loss of information.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Holter Tape Address Method for Start/Stop Scanning Without Loss of Data

When a tape which contains EKG analog information is stopped during hig speed computer or manual processing, an undesirable loss of data or discontinuity in the EKG signal results when the tape is restarted. This article shows a method for resynchronizing the EKG signal on a restarted tape so that the EKG analysis computer program can continue processing the EKG waveform without loss of information.

A modulo N address is recorded on an address track of the EKG tape. N is determined by the start and stop distances of the playback tape transport. For this article, N = 16 is chosen as an example.

A method for synchronizing the address decoder is required whenever the EKG tape is started. A string of synchronizing characters, hexadecimal FFD, is placed ahead of each N address characters. The FF characters consisting of eight "1" bits are used for bit sychronization of the address decoder, and the D character is used for character synchronization.

During computer scanning, the control logic retains the current address plus a location count. The location count contains the number of address bits read past the last address character. When the tape is stopped, the address and location count are saved. When tape processing is restarted, the tape is reversed past the last input data, stopped, and then started in the forward direction.

The address decoder achieves bit synchronization by reading the string of binary "1" bits in the first FF characters and achieves character synchronization by reading the D character. (Other characters can be used for this purpose.)

The address search logic compares the incoming addresses with the saved address and the incoming bit count with the saved location count. When the addresses and counts compare, the tape is repositioned, and computer processing of the EKG data can resume.

If the normal heart beat density is 24 beats per inch and the recording density of the address track is 240 bits/inch, then this method permits a 10% resolution of the tim...