Browse Prior Art Database

Analog Multiplexing Device

IP.com Disclosure Number: IPCOM000089742D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Debord, P: AUTHOR [+2]

Abstract

Shown above is a time-domain multiplexing device which allows analog signals applied on its input lines to be transmitted on a common output line.

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Analog Multiplexing Device

Shown above is a time-domain multiplexing device which allows analog signals applied on its input lines to be transmitted on a common output line.

The multiplexing device comprises four similar circuits 1, 2, 3 and 4 having input terminals IN1 to IN4. These input terminals are provided with signals to be multiplexed and presented to output terminal OUT.

The four circuits have the same configuration, and similar elements in circuits 1 to 4 have the same references with corresponding suffixes 1 to 4.

Each circuit comprises two transistors T1 and T2 having their emitters connected together to current source S1 through transistor switch T3, the conduction of which is controlled through a signal SEL applied at its base. The collector of transistor T2 is connected to a second current source S2 and to voltage follower transistor T4.

The input signal to be multiplexed is applied to the base of transistor T1 through capacitor C1 and biasing resistor R1. The base of transistor T2 is connected to resistor R2 which has the same value as resistor R1.

Output terminal OUT is connected to common node A of resistors R2-1 and R2-2 and to common node B of resistors R2-3 and R2-4.

Each circuit also comprises diode D1 and transistor T5 having its emitter connected to the emitter of transistor T3 and its collector connected to the base of transistor T4. The conduction of transistor T5 is controlled by a signal SEL applied at its base. Diode D1 prevents break...