SU1280406A1 - Non-linear converter - Google Patents

Abstract

The invention relates to the industrial means of communication and can be used in the development of analog-digital converters used in television technology. The purpose of the invention is to increase accuracy and speed. The nonlinear converter contains an operational amplifier 1, a voltage converter - current 2, a device for fixing the signal level 3, sources of 4,5,6 and 7 current, key transistors 8,9,10 and 11, shunt diodes 12,13,14 and 15, resistors 16, 17 and 18 of the collector load, the source 9 of the reference voltage. This goal is achieved by introducing the third resistor 18 of the collector load, operational amplifier 1, unit 3 for fixing the signal level and source 19 of the reference voltage. Error compensation is achieved in order. what is to the input.: voltage converter - current 2 is supplied with a signal from the output of operational amplifier 1, and the device for fixing the signal level ensures the setting of such an initial level that corresponds to the beginning of the transfer characteristic of the nonlinear converter. 2 Il. u 00 4 o G5

Description

11280Д06

The invention relates to the industry of communications and can be used in the development of analog-to-digital converters used in television technology. five

The purpose of the invention is to improve the accuracy and speed of the nonlinear converter.

FIG. Figure 1 shows the block diagram of the nonlinear transformation of bodies; in fig. 2 - diagrams of non-linear converter operation.

Nonlinear converter contains operational amplifier 1, converter 2 voltage - current, device 3 fixing the signal level, 4-7 current sources, key transistors 8-11, shunt diodes 1215, collector load resistors

16.17 and 18, source 19 of the reference voltage.

Nonlinear Converter works as follows.

When a zero voltage Ug is applied (Fig. 2a) to the input of a voltage-current converter 2, its output current is zero. Equal currents of magnitude I sources of currents 4-7 flow through the key transistors 8-11, at the base-emitter transitions of which the voltages are equal. Thus, equal voltages are applied to the leads of the shunt diodes 12-15, the shunt diodes are closed and the current does not flow through them. Through the resistor 35 and 16 / G / collector load, the magnitude of each of which is equal to R, currents 21 flow and they fall equal to the voltage:

, Ueb, U2-Ul 0.

At the same time on the resistor 18 collector load voltage drop

20

25

thirty

pe will increase to a potential sufficient to open the shunt diode 12. At this point,, UBbix U2-Ul IR,, g (Fig. 26, c, d, e).

A further increase in the output current of the voltage converter - current 2 will lead to the current source 5 current branching off, which will decrease the current through the key transistor 9, collector load resistors 17 and 18, and so on; Thus, a monotonic change in voltage at the input of the voltage converter - current 2 will lead (in the absence of hardware errors) to a monotonic change in voltage drop U3 (Fig. 2d) on the resistor of the collector load 18 and the triangular voltage form) ((FIG. 2c) between the para-phase terminals of the device.

The error compensation is achieved by the fact that a signal 2 is sent to the input of a voltage converter, a signal is output from an operational amplifier 1, an input signal is fed to one of the inputs, and a feedback signal from a resistor 18 to the other. to form a voltage at the input of the converter voltage - - current 2, which will cause a change in the current Ig, x in such a way that it compensates for errors caused by the final value of the resistance of the current generators, the voltage - current, nonlinearity yennost elements of the scheme.

U.X

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40

of equals 4lR, o (Fig. 2b, c, d, d). WITH

The device 3 for fixing the signal level provides the setting of such an initial level, which corresponds to the beginning of the transfer characteristic of the nonlinear converter by increasing the voltage Ug (Fig. 2a) 5 P connecting the first input of this device to the anode of the shunt diode 15 and the middle transfer characteristic of the nonlinear converter when connecting the first input of the device fixing the level to the anode of the diode 13.

at the input of the voltage converter - current 2 at its output the current increases. In this case, a portion of the current of the current source 4 is coupled to the voltage converter — current 2 and the current through the transistor decreases. This decreases the voltage drop across the resistors 16 and 18. This occurs as long as the converter voltage is current 2 does not exceed the value of the current I of the first source 4 current. Once this happens, the emitter junction — the base of the key transistor B — closes and the potential at its emitte50

55

Claims (1)

11 The invention relates to the industrial use of communications and can be used in the development of analog-digital converters used in television technology. The purpose of the invention is to improve the accuracy and speed of the nonlinear converter. FIG. 1 shows a block diagram of a nonlinear converter; in fig. 2 - diagrams of non-linear converter operation. Nonlinear converter contains operational amplifier 1, converter 2 voltage - current, device 3 fixing the signal level, sources 4-7 current, key transistors 8-11, shunt diodes 1215, resistor collector load 16.17 and 18, reference source 19 tension Nonlinear Converter works as follows. When a zero voltage Ug is applied (Fig. 2a) to the input of a voltage-current converter 2, its output current is zero. Equal currents of magnitude I sources of currents 4-7 flow through the key transistors 8-11, at the base-emitter transitions of which the voltages are equal. Thus, equal voltages are applied to the leads of the shunt diodes 12-15, the shunt diodes are closed and the current does not flow through them. Through the resistors 16 and G / collector load, the value of each of which is equal to R, currents 21 flow and they drop equal voltages:, Ueb, U2-Ul 0. At the same time on the resistor 18 of the collector load the voltage drop from is 4lR, o (Fig. 2b, c, d, d). As the voltage Ug increases (Fig. 2a at the input of the converter, the voltage of the current 2 at its output increases the current. In this case, part of the current of the current source is branched into the converter voltage-current 2 and the current through the transistor decreases. This decreases the voltage drop on resistors 16 and 18, this happens as long as the voltage of the converter is the current 2 does not exceed the value of the current I of the first current source 4. As soon as this happens, the emit-to-emitter transition - the base of the key transistor B will close and the potential at its emitt 6 re increase to potential sufficient to open the shunt diode 12. At this point,, UBbix U2-Ul IR,, g (Fig. 26, c, d, e). Further increase in the output current of the converter voltage of current 2 will cause the current source 5 to branch off. which will cause a decrease in the current through the key transistor 9, resistors 17 and 18 of the collector load, and so on; Thus, a monotonic change in voltage at the input of the voltage converter - current 2 will result (in the absence of hardware errors) to a monotonous change in voltage drop U3 ( FIG. 2d) on the resistor of the collector load 18 and the triangular voltage form) ((Fig. 2c) between the paraphase terminals of the device. Error compensation is achieved by the fact that a signal 2 is supplied to the input of the voltage converter 2, from the output of the operational amplifier 1, from the inputs to which the input signal is supplied, and to the other - the feedback signal from the resistor 18. As a result, the operational amplifier 1 will generate such a voltage at the input of the voltage converter 2 that will cause the current Ig, x to change in such a way that it compensates tons of errors caused by the final value of the resistance of the current generators, the converter voltage - current, the nonlinearity of the circuit elements. The device 3 fixing the signal level ensures that an initial level is set that corresponds to the beginning of the transfer characteristic of the nonlinear converter P connecting the first input of this device to the shunt anode diode 15 and the middle transfer characteristic of nonlinear converter when connecting the first input of the level fixing device to the anode of diode 13. Fore ula and zobretend nonlinear converter comprising n current sources, key n transistors, p shunt diodes, two collector load resistor and the voltage converter