SU1246368A1 - Method of analog-to-digital conversion - Google Patents

Abstract

The invention relates to the field of optoelectronics, in particular, to methods of converting analog electrical signals to digital code. The invention improves the conversion accuracy by integrating the signal into interferometric modulators, in which the spatial distribution of the generated voltages along the interferowave, which is directed opposite to the coherent light pulse propagating in the optical fiber, occurs. When integrating, the error is reduced due to protective filtering that suppresses the sampling frequency, and, moreover, the dispersion rate of propagation of the electromagnetic signal in the electro-optical material, which reduces the aperture conversion time in the instant sampling method, is not among the parameters limiting the accuracy and speed in the conversion method with integrating sample, 1 Il. (L with ND 4ib O) CO O) 00

Description

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The invention relates to optoelectronics, in particular, to methods for converting analog electrical signals to digital code.

The purpose of the invention is to improve the accuracy of the conversion.

The drawing shows a functional diagram of the device that implements the proposed method.

The device contains an optical coherent radiation source 1, an optical waveguide 2, supplying light to interferometric modulators 3, the outputs of which through threshold devices 4 are connected to the outputs 5 of the device. In each interferometric modulator 3 the optical waveguide 2 branches into two separate waveguides, one of which passes between the electrodes 6 connected from the output side of the interferometric modulator 3 by conductors 7 to one of the outputs of the voltage divider 8, the input 9 of which is the input of devices , On the input side of each interferometer modulator-parameter its electrodes 6 are connected via a resistor 10,

Said connection of electrodes 6 with conductors 7 and resistor U, provided that this resistance is equal and the output resistance of the divider to the impedance of the strip electrodes, ensures the spatial distribution of voltages along the electrodes of the interferometric modulators in the form of a running wave and the direction of this wave towards the coherent pulse Sveta. In this case, the principle of integral samples of the values of the signal being converted is realized, i.e. The light intensity at the output of the interferometric modulator is not determined by the instantaneous value of the converted electric signal, but by the total effective effect of this signal during the optical signal's travel time relative to the electric one. This travel time determines the limits of integration. Since for operation in the mode of integrating samples, it is necessary that the integration limits in all bits be the same, and this time is determined by the size of 1246368

L torus 3 must be identical. In order to ensure the difference in modulation characteristics of modulators 3, different voltages for each modulator are applied to electrodes 6, obtained by converting the amplitude of the input signal according to a binary law:

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and

v1x

, and 2

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where i 0,1,2,. ,,, (p-1);

p is the number of modulators 3 in the APT.

The necessity of converting Ugj, precisely according to binary law, explains that in order to convert Ug to binary code, the frequency of changes in the light intensity with the change and at the outputs of any two modulators 3 corresponding to two adjacent bits of the binary number must be two times different, for which it is necessary to apply simulating voltages differing in amplitude at the electrodes of these modulators.

The code on the BB inputs of the threshold devices 4 is formed by converting coherent light pulses into voltages into them and comparing them with noporoBbn-Di voltage levels equal to half the maximum value of the converted voltage.

The increase in accuracy in this method is explained by the use of integral signal samples, at which dynamic errors are significantly reduced.

Fore. invented mule

An analog-to-digital conversion method based on electro-optical modulation of light between the electrodes of interferometric modulators and consisting in forming from the input signal the corresponding voltages on the electrodes of each interferometric modulator, performing a spatial distribution of the generated voltages along the electrodes of the interferometric modulators in the form of a running waves with simultaneous input into each inte-J5 ferometric modulator of coherent light pulses, forming phase delay of coherent light pulses in one of the optical fibers of each

mi, electrodes in the direction along the optical waveguide, then it follows that these dimensions in all mod10

and

v1x

, and 2

where i 0,1,2,. ,,, (p-1);

p is the number of modulators 3 in the APT.

The necessity of converting Ugj, precisely according to the binary law, is explained by the fact that for converting Ug into a binary code, the frequency of changes in the light intensity with the change and at the outputs of any two modulators 3 corresponding to two adjacent bits of the binary number must differ twice What is necessary for the electrodes of these modulators is to apply simulation voltages differing in amplitude.

The code on the BB inputs of the threshold devices 4 is formed by converting coherent light pulses into voltages into them and comparing them with noporoBbn-Di voltage levels equal to half the maximum value of the converted voltage.

The increase in accuracy in this method is explained by the use of integral signal samples, at which dynamic errors are significantly reduced.

Fore. invented mule

An analog-to-digital conversion method based on electro-optical modulation of light between the electrodes of interferometric modulators and consisting in forming from the input signal the corresponding voltages on the electrodes of each interferometric modulator, performing a spatial distribution of the generated voltages along the electrodes of the interferometric modulators in the form of a running waves with simultaneous input into each interferometric modulator of coherent light pulses, forming phase delay of coherent light pulses in one of the optical fibers of each

interferometric modulator and code generation by converting coherent light pulses. at the outputs of interferometric modulators into voltage and comparing them with threshold voltage levels equal to half the maximum value

The transformed voltage is characterized in that, in order to increase the conversion accuracy, when coherent light pulses are introduced into each interferometric modulator, they are guided towards the propagation of a traveling wave.

"Editor V. Petrash

Compiled by A.Titov, g

Tehred L.Oleynik Proof-reader I.Erdeyi

Zack; G4021 / 55 Circulation

VNII1SH State Committee 1.y.d

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab.,

.; p; y1; o; c; ; e ;; o1 ;; olig ;; fy:; e; k; z ;;; G. Uzhhorod, st. project, 4,

Claims (1)

Claim A method of analog-to-digital conversion, based on electro-optical modulation of light between the electrodes of interferometric modulators and consisting in generating from the input signal the corresponding voltages on the electrodes of each interferometric modulator, performing a spatial distribution of the generated voltages along the electrodes of the interferometric modulators in the form of a traveling wave with simultaneous input into each interferometric modulator coherent light pulses forming phases the delay of coherent light pulses in one of the optical fibers of each interferometric modulator and _ generating a code by converting coherent light pulses at the outputs of interferometric modulators to voltage and comparing them with threshold voltage levels equal to half the maximum value of the converted voltage, characterized in that, with In order to increase the accuracy of conversion, when coherent light pulses are introduced into each interferometric 5 modulator, they are directed towards th traveling wave. • Editor V. Petrash