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Differential Resonant Charge Transfer

IP.com Disclosure Number: IPCOM000092357D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Avers, CD: AUTHOR [+2]

Abstract

The differential resonant charge time division switching circuit combines resonant transfer and sampled data clamping techniques in a circuit utilizing active filters. The basic operation of an individual, differential resonant charge transfer path appears in the drawings. The input voltage V(0)is bandlimited to a bandwidth of f(s)/2 by filter 10,where f(s) is the sampling rate of switch 20 and 1/f(s) is equal to T. The output impedance of filter 10 is low.

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Differential Resonant Charge Transfer

The differential resonant charge time division switching circuit combines resonant transfer and sampled data clamping techniques in a circuit utilizing active filters. The basic operation of an individual, differential resonant charge transfer path appears in the drawings. The input voltage V(0)is bandlimited to a bandwidth of f(s)/2 by filter 10,where f(s) is the sampling rate of switch 20 and 1/f(s) is equal to T. The output impedance of filter 10 is low.

During each sampling interval T is equal to pi LC and a charge is transferred from capacitor 12 to capacitor 22. Filter 20 has a high input impedance and voltage V(2) therefore remains essentially constant between sampling intervals. The amplitudes of the resonant transfer current impulses are proportional to the difference between signal samples rather than the full amplitude of the signals.

Drawing 2 shows a sine-wave signal V(0), V(1) passed through active low pass filter 10 and used to charge capacitor 12. The voltage level V(2) of capacitor 22 is charged to the voltage level of capacitor 12 at every sampling interval. Whenever sampling switch 20 is closed, the voltage level of capacitor 22 is brought to the level of capacitor 12 by current flow i, shown in drawing 3, from the capacitor having the higher charge to the capacitor having the lower charge. Since only the difference in charge is transferred, there is a correspondingly lower current flow on the time-divided...