SU1287272A1 - Interval-to-voltage converter - Google Patents

Abstract

The invention can be used in automatics when converting width-modulated signals to voltage. The purpose of the invention is to improve the accuracy of conversion and the expansion of the dynamic range of the converted signal. The converter contains a source of direct current 1, a block of 3 discharge circuits, keys 4 and 5 of commutation, blocks (IT) 6 and 7 accumulative, a switch of 8 bits and block 10 of control. A shaper of 2 bipolar pulses, a key of 9 bits and a difference block 11 are inserted into the device. Thanks to the introduction of the recharging process, such a form of signals is obtained on the BN 6 and 7 byways, that their immediate difference forms the output signal of the converter at each time instant. Thus, a direct connection of the BN 6 and 7 is provided to the difference unit 11, as a result of which, when the input signal changes, the output resistance of the BN 6 and 7 remains unchanged, and consequently the conversion accuracy is improved. In addition, the dynamic conversion error is reduced by eliminating output ripple. 4 il. (L with ND 00 1C h 1C

Description

Fm, g. /

The proposed interval-voltage converter relates to a pulse technique, concerns the issue of converting latitude-modulated signals to voltage, and can be used in automation, telemechanics and computer technology.

The aim of the invention is to improve the accuracy of conversion and expansion of the dynamic range of the converted signal.

Figure 1 presents the functional diagram of the proposed Converter; FIG. 2 — timing charts of operation — the devices of FIG. 3 and 4 are examples of a specific embodiment of the converter.

The interval-voltage converter contains a source of direct current 1, a driver of 2 bipolar pulses, a block of 3 charge circuits, a key

40

Chi 4 and 5 are commuting, blocks 6.7 are cumulative, keys are 8.9 bits, control unit Yu and difference block 25 11. At the same time, the input bus is connected to the input of control unit 10, one of the outputs of the block 3 of charging circuits is connected with the input of the first switching key 4, the output of which is connected to the 30 first input of the first storage unit 6, the first input of the second storage unit 7 is connected to the output of the second switching key 5, the output of the source 1 of direct current 35 is connected to the input of the driver 2 bipolar pulses, output which is connected to the entrance locking circuit 3, the second output of which is connected to the input of the second switching key 5, the first output of the control unit 10 is connected to the control input of the bipolar pulse former, the second output of the control unit 10 is connected to the control input of the second switch 9, the first and the second outputs of which are connected to the corresponding inputs of the second storage unit 7, the fourth output of the control unit 10 is connected to the control input of the first key of the 8th digit, the first and second outputs of which are connected to the corresponding inputs of the first control pitelnogo unit 6, the third and fifth control unit 10 outputs cos-55 dineny with the control inputs of the first to the second switching keys sootvetstvenyo 4 and 5, wherein the outputs are connected to the storage units

five

five

fO

15

25 o 30 35 - -50 -55 87272 2

the inputs of the differential unit 11, the output of which is connected to the output bus. The first inputs of the And 13 and 14 elements are connected to the direct and inverse outputs of the trigger 12, respectively, the second inputs of the And 13 and 14 elements are combined and connected to the input of the control unit, the outputs of the And 13 and 14 elements are connected to the inputs of the HE elements 15 and 16, respectively. which, as well as the outputs of the elements 13 and 14 and the direct output of the trigger, are connected respectively to the third, fifth, fourth, second and first outputs of the control unit 10.

The Converter operates as follows.

Input pulses (Q-I diagram of the converted interval corresponds to a negative pulse) are sent to control unit 10, the output of which produces pulses equal in duration to the period of the input signal (diagram 6), as well as pulses equal to the pause of the input signal and following alternately through the period of the input signal signal (diagrams fe, d), and inverse signals (diagrams j, m).

On the driver 2, controlled by pulses from control unit 10 (diagram S), bipolar signals are formed (diagram e).

20

At the initial moment of time to, the key B, controlled by positive pulses from the fourth output of control unit 10 (diagram b) and the switching key 4, controlled by pulses from the third output of control unit 10 (diagram g), is opened, which ensures d of the capacitor of the storage unit 6 and maintaining this state until time tj (diagram u).

Starting from the moment of time, the 8th discharge closes and the voltage at the output of the blocks begins to increase linearly, since a positive polarity impulse comes from its input from the driver 2 of the diagram).

At time tt, key 4 is closed (diagrams), disconnecting accumulative unit 6 from the charging circuit, thus observing the voltage storage mode.

Starting from the time point t the key 4 opens, passes to the input

cumulative unit 6 from the imaging unit 2, a negative polarity pulse equal in amplitude to a positive polarity pulse. In this case, the capacitor of accumulator block 6 is recharged to zero (time instant t,), since charge time i (tj) and discharge time (C – tj) and discharge time (c – t) is equal to the duration of the information signal ut - t.,. Then (t - tj), the 8th key of the bit is opened (diagram b), maintaining the zero level on the capacitor of the accumulation unit 6, then the process is repeated.

Each time period, the bit switch provides stabilization of the output signal by tying to zero, which is especially important when using integrals on operational amplifiers, in which the output voltage and the bias current of the amplifier would slip without such a discharge.

Similarly, the second storage unit 7 (diagram k) is connected, which is connected to the imaging unit 2 via a key controlled by pulses of the control unit 10 (diagram d) and discharged by a key 9, controlled by a pulse co in diagram g. In this case, pulses are formed in the storage unit, similar to those of storage unit 6, but negative polarity (K diagram) with respect to the zero level.

In difference block 11, the voltage of accumulative block 7 (diagram k) is subtracted from the voltages of accumulative block 6 (diagram and), the result is shown in the diagram

A change in the duration of the information signal in the direction of decreasing CdHz dtj) or in the direction of increasing (Atg Aty) causes a change in the output signal after the termination of the information pulse without the presence of

unit, resulting in a change in the input signal, the output resistance of the storage units remains unchanged, and, consequently, the conversion accuracy is improved. Indeed, when used as a difference unit 11, for example, a differential amplifier, the output voltage of the converter is defined as

V -VK 14

 in

Where

RBXROC resistance at the input of the amplifier,

feedback resistance

VK is the output voltage of the storage unit. When the transmission coefficient K 1 RO 1TS., Then

 8S) from

 V.

Similarly, connecting a differential amplifier to a known device as a buffer will provide, at the output of the converter, a voltage according to the formula

tt tt os

ri to

eblX

 one

ak

RK "

one

tCft

+ - t

 Oh

dk

Ka

l-w

When using amplifiers with high input resistance, the input resistance can be chosen large, which will reduce the conversion error, while in the proposed converter, this error is completely eliminated when using any amplifiers.

In addition, the direct connection of the storage units to the difference unit provides up to

voltage corresponding to the process 50 is the positive positive effect - working out.

Due to the introduction of the recharge process, such a form of signals at the outputs of storage units was obtained, that their immediate difference in 55 each moment in time forms the output signal of the converter. In this way, the accumulative blocks are directly linked to mismatching the dynamic conversion error by eliminating output ripple. The component of the error introduced by the storage unit in the storage mode is also reduced, since the storage time corresponds to the duration of the pause between information pulses, while in the additional positive effect -

reduction of dynamic conversion error due to exclusion of output ripple. The component of the error introduced by the storage unit in the storage mode is also reduced, since the storage time corresponds to the duration of the pause between information pulses, while in the prototype the storage time is equal to the period of information pulses.

Indeed, the change in voltage of the storage unit D V in the storage mode corresponds to

AV. ; c 1 V. dt 5 - VK, (T-t, ".

Similarly for the prototype

v, p - v, dt - - - V ,. t,

to about

where RK is the key resistance in the closed state; information pulse duration; T - the period following the input

pulses.

The range of variation of the input signal is determined, on the one hand, by the sensitivity threshold of the storage units, on the other hand, by the pulse width required for the full discharge of the storage capacitor units.

When using integrators On operational amplifiers, the lower limit of convertible intervals can be close to zero. Since in the static mode, the spacing of the capacitor is provided by recharging the capacitor to zero, and the discharge keys only support this state, the upper limit of the input pulse is close to the value of the pulse repetition period, which differs by the duration required by the circuit elements, t. e. determined by their speed.

formula of invention

The interval-voltage converter containing a DC source, a charging circuit block, two switching keys, two storage blocks, a discharge key, a control block containing a trigger, an input and an output bus, the input bus connected to the trigger input of the control block , one of the outputs of the charge circuit block is connected to the input of the first

the switching key, the output of which is connected to the first input of the nepBoi o accumulation unit, the first input of the second accumulation unit is connected

with the release of the second switching key, different from the fact that, in order to improve the accuracy of conversion and expansion of the dynamic range of the signal being converted, into it

a shaper of bipolar pulses, a second key of the discharge and a difference block are introduced, while the output of the direct current source is connected to the input of the shaper of bipolar pulses,

the output of which is connected to the input of the charge circuit unit, the second output of which is connected to the input of the second switching key, the first output of the control unit is connected to the control input of the bipolar pulse generator, the second output of the control unit is connected to the control input of the second key of the discharge, the first and the second outputs of which are connected with the corresponding

the inputs of the second storage unit, the fourth output of the control unit — with the control input of the first key of the discharge, the first and second outputs of which are connected to the corresponding

the inputs of the first storage unit, the third and fifth outputs of the control unit are connected to the control inputs of the first and second switching keys, respectively, and the outputs

accumulative blocks are connected to the inputs of the difference block, the output of which is connected to the cell bus, and the control unit additionally contains two elements AND two elements NOT, the first inputs of the first and second elements AND are connected to the direct and inverse outputs of the trigger, respectively, the second inputs of the first and second elements And are combined and connected to the input of the control unit,

the outputs of the first and second elements And. connected to the inputs of the first and second elements, respectively, the outputs of which, as well as the outputs of the first and

The second elements And the direct output of the trigger are connected respectively to the third, fifth, fourth, second and first outputs of the control unit.

.3

9ut.

Claims (2)

•Claim The interval-voltage converter containing a DC source, a block of charge circuits, two switching keys, two storage blocks, a discharge key, a control unit containing a trigger, input and output buses, the input bus being connected to the trigger input of the control unit, one of the outputs block of charge circuits connected to the input of the first 2 6 switching key, the output of which is connected to the first input of the first storage unit, the first input of the second storage unit is connected to the output of the second switching key, characterized in that, in order to increase the conversion accuracy and expand the dynamic range of the converted signal, a bipolar pulse shaper is introduced into it , the second discharge key and the difference block, while the output of the DC source is connected to the input of the bipolar pulse former, the output of which is connected to the input of the block charge, the second output of which is connected to the input of the second switching key, the first output of the control unit is connected to the control input of the bipolar pulse shaper, the second output of the control unit with the control input of the second discharge key, the first and second outputs of which are connected to the corresponding inputs of the second storage unit, the fourth the output of the control unit with the control input of the first discharge key, the first and second outputs of which are connected to the corresponding inputs of the first storage unit, the third and fifth fifth control block outputs are connected to control inputs of the first and second switching keys, respectively, wherein the outputs of storage units are connected to the inputs of the differential unit, whose output is connected to the output _bus; moreover, the control unit additionally contains two AND elements and two NOT elements, the first inputs of the first and second elements AND are connected to the direct and inverse outputs of the trigger, respectively, the second inputs of the first and second elements AND are connected to the input of the control unit, the outputs of the first and second elements AND . connected to the inputs of the first and second elements are NOT, respectively, the outputs of which, as well as the outputs of the first and second elements And and the direct output of the trigger are connected respectively to the third, fifth, fourth, second and first outputs of the control unit. “G'GTCH —VtJ ~ Ί 1 G? G ΓΊ G- Ί I 1 π P Γ1 g ’ eleven II ~ LT ιΙ 1