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Coding Device for Delta Modulation

IP.com Disclosure Number: IPCOM000091490D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Desblache, A: AUTHOR

Abstract

The device allows the classical coding of the delta modulation, using less elements and in more compact form.

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Coding Device for Delta Modulation

The device allows the classical coding of the delta modulation, using less elements and in more compact form.

The modulation principle is shown in drawing A and the classical circuit appears in drawing B. During a given time interval, the faster the received signal is increasing, the greater is the number of delivered pulses, this occurring until a limit M where the number of pulses delivered by the sampling generator is reached. Similarly, when signal is decreasing, the number of pulses becomes less and less important until a slop M from which there is realized the minimum number of pulses, the number determined by the discharge time constant of the integrator circuit. There is obtained at a sampling instant a pulse at the device output, when single-shot S-S is started, i. e., if signal Si is greater than the value at the integrator terminals, this comparison being made by subtractor Sb.

The device in drawing C comprises a magnetic core. Its polarization is produced by signal Si and by the current provided through transistor T1, the current being a function of the charge of the integrator circuit. This realizes comparator Sb of drawing B. If signal Si increases sufficiently in relation to the value at the integrator terminals, the core switches. Then the sampling pulse resets it to a polarization situation on the lower part of the hysteresis curve. Simultaneously through T2 a coding pulse is delivered at the device output while...