Browse Prior Art Database

Pulse Amplitude Modulator

IP.com Disclosure Number: IPCOM000093886D
Original Publication Date: 1966-Mar-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Rothauser, E: AUTHOR [+2]

Abstract

The modulator periodically transmits the instantaneous amplitude of the signal being modulated. The circuit has input terminal 2 that receives the sinusoidal signal that is to be modulated. It has another input terminal 3 that receive s the modulation signal. The signal portion at terminal 2 that coincide s with the modulating signal at terminal 3 appears at output terminal 4. The latter is connected to a utilization device represented by resistor 5.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 96% of the total text.

Page 1 of 2

Pulse Amplitude Modulator

The modulator periodically transmits the instantaneous amplitude of the signal being modulated. The circuit has input terminal 2 that receives the sinusoidal signal that is to be modulated. It has another input terminal 3 that receive s the modulation signal. The signal portion at terminal 2 that coincide s with the modulating signal at terminal 3 appears at output terminal 4. The latter is connected to a utilization device represented by resistor 5.

Transistor 6 is connected to produce the modulated waveform at its emitter terminal. Its collector is connected to potential +V. Its base terminal is connected to terminal 2 to receive the signal to be modulated. Its emitter is connected by resistor 7 to terminal 3 to receive the modulating signal.

The modulating signal switches between a value appropriate to turn off transistor 6 and a value that is appropriate to cause transistor 6 to operate as an emitter-follower. When transistor 6 operates as an emitter-follower, it produces the modulated signal at its emitter terminal.

The signal developed across resistor 7 is coupled to output terminal 4 by transistor 8. This is connected with resistor 9 in an emitter-follower configuration.

With the addition of transistor 8, resistor 7 in the circuit of transistor 6 can have a high value. Preferably resistor 9 is given a nonlinear value that is appropriate to compensate for nonlinearity in the base-emitter resistance of the transistors.

1

Page 2 of 2...