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Ring Modulator

IP.com Disclosure Number: IPCOM000094302D
Original Publication Date: 1966-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Blondeau, H: AUTHOR

Abstract

The ring modulator, derived from the conventional ring modulator, has both its input and output transformers replaced by microcircuits playing the same role.

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Ring Modulator

The ring modulator, derived from the conventional ring modulator, has both its input and output transformers replaced by microcircuits playing the same role.

The input circuit inverts via a transistor phase converter device I and performs current addition via a bridge network of four equal resistances R1...

R4. The output circuit performs current addition via an identical resistance bridge R5... R8, and differential measurement via a differential amplifier DA. The ring itself comprises diodes D1...D4.

The square-wave carrier f1 is derived from a flip-flop. The modulating frequency f2 is furnished by a low-frequency supply S.

With no carrier on, should the low-frequency modulating signal be going positive, point A is substantially positive with respect to point B and current flows through D1 and D3. There is no current into the output resistance bridge. When the modulating signal goes negative, point B gets positive with respect to A and current flows into D2 and D4. There still is no current through the output bridge.

Should the carrier be on, D1 and D2 are enabled whenever point C is positive with respect to point D. The current generated from the modulating signal is applied to the output bridge and adds or subtracts from the current generated by the carrier. Such is in accordance with its polarity, thus making this bridge unbalanced. Such unbalance, sensed through amplifier DA, furnishes both sidebands f1+f2, and f1-f2, exclusive of the carrier...