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Browse Prior Art Database

MUSICAL MEM-O-LERT

IP.com Disclosure Number: IPCOM000005643D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2001-Oct-23
Document File: 1 page(s) / 49K

Publishing Venue

Motorola

Related People

John McKee: AUTHOR [+2]

Abstract

A simple modification to existing pager designs will provide a "Musical Mem-0.Lert" feature. The above block diagram shows a typical pager having an NPN transistor output for driving a vibrator motor The NPN collector is connected to the negative supply of the melody generator IC. This IC is of the type used in musical greeting cards. When the pager is in the MEM mode and a page is received the VIB pin goes low. The melody IC then drives the ceramic transducer with the preprogrammed tune for the duration of the alert, usually about 12 seconds, the VIB pin then goes high and the melody IC is turned off.

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MOlYlROLA Technical Developments Volume 7 October 1987

MUSICAL MEM-0-LERT

by John McKee and Greg Snowden

   A simple modification to existing pager designs will provide a "Musical Mem-0.Lert" feature. The above block diagram shows a typical pager having an NPN transistor output for driving a vibrator motor The NPN collector is connected to the negative supply of the melody generator IC. This IC is of the type used in musical greeting cards. When the pager is in the MEM mode and a page is received the VIB pin goes low. The melody IC then drives the ceramic transducer with the preprogrammed tune for the duration of the alert, usually about 12 seconds, the VIB pin then goes high and the melody IC is turned off.

   When the melody IC is driving the transducer the support circuit's transducer drive outputs are high im- pedance. When the support is driving the transducer (normal audio mode) the melody IC's drivers are high impedance.

   If the product uses an electromagnetic rather than aceramic transducer, the additional bufferand OR func- tion are required since the transducer typically represents too low an impedance to be driven directly by the melody IC. The buffer and OR function may be as simple as a transistor with base connections through sep- arate resistors to both the support and melody IC circuits.

The flatness of the audio response will be effected by the resonant characteristic of the transducer, however and an acceptable sound is still achievable since the t...