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Hole Sensing Utilizing Time Domain Reflectometry

IP.com Disclosure Number: IPCOM000095109D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Hill, YM: AUTHOR [+2]

Abstract

A pneumatic record medium reading apparatus is shown in A. This apparatus senses holes in a record medium RM 2. Such is effected by detecting the positive pressure pulses PPP 172 shown in B. PPP 172 are reflected by holes 154 interposed along the boundary wall of the path of a pressure wave PW 168. The latter moves parallel to RM 2 and moving within a pressure line PL 130. PL 130,is connected to an air pressure source PS 138. This maintains the air within PL 130 at a constant pressure. A probe microphone PM 142 is placed within PL 130 to sense PPP 172. The other end of PL 130 terminates in an open ended horn-shaped element HE 146.

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Hole Sensing Utilizing Time Domain Reflectometry

A pneumatic record medium reading apparatus is shown in A.

This apparatus senses holes in a record medium RM 2. Such is effected by detecting the positive pressure pulses PPP 172 shown in
B. PPP 172 are reflected by holes 154 interposed along the boundary wall of the path of a pressure wave PW 168. The latter moves parallel to RM 2 and moving within a pressure line PL 130. PL 130,is connected to an air pressure source PS 138. This maintains the air within PL 130 at a constant pressure. A probe microphone PM 142 is placed within PL 130 to sense PPP 172. The other end of PL 130 terminates in an open ended horn-shaped element HE 146.

Chopper disk CD 148 is placed adjacent and in close proximity to HE 146. CD 148 is attached to drive shaft DS 150. This is driven in synchronism with a card transport not shown. It is formed with port P 152 which matches the opening of HE 146. Roller element RE 156 is equipped with a plurality of cavities 160 each of which comprises an individual pressure source. Although the RE 156, RM 2, and PL 130 surfaces are not sealed, PW 168 is relatively constant. RE 156 is driven in synchronism with the card transport by shaft 158.

The venting of PL 130, by P 152 develops a lower pressure level PL 170 at HE 146. The pressure wave travels to the left past PM 142. PL 170 then travels past the possible hole locations 154. When a hole 155 exists in RM 2, the stored pressure in the corresponding cavit...