SU1642481A1 - Time and pulse multiplier device - Google Patents

Abstract

The invention relates to analog computing, is intended to convert information and can be used in measuring converters for various purposes, in particular in devices for measuring power. The purpose of the invention is to improve the accuracy of the device. The device contains the first and second inverters 1, 6, the first and second amplitude-pulse modulators 2, 7, the first and second pulse-width modulators 3, 8, the generator 4 is a triangular voltage, the source 5 is the reference voltage, averaged 9, key 10, summing integrator 11, trigger 12, reference frequency generator 13. By introducing blocks 1, 4, 6, 7, 8, 9, the value of the output frequency of the trigger 12 is independent of the value of the reference voltage of the pulse-width modulator 3. 2 Il. cl

Description

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The invention relates to analog computing, is intended to convert information and can be used in measuring converters for various purposes, in particular in power measurement devices.

The aim of the invention is to improve the accuracy of the device.

FIG. 1 shows a functional diagram of the time pulse multiplying device; in fig. 2 - time diagrams that show his work.

The pulse multiplying device (Fig. 1) contains the first inverter 1, the first pulse-amplitude module - tor2, the first pulse-width modulator 3, the generator 4, the voltage of a triangular shape, the source 5 of the reference voltage, the second inverter 6, the second amplitude- pulse modulator, second pulse-width modulator 8, averaging filter 9, key 10, summing integrator 11, D-flip-flop 12, generator 13 of the reference frequency.

FIG. 2 are indicated: Ui is the voltage proportional to the first signal multiplier; Da is the voltage proportional to the second signal multiplier; Uz is the triangular voltage from the output of the generator 4; U is the voltage at the output of the first pulse-width modulator 3; Us is the voltage at the output of the first pulse-amplitude modulator 2; Ue is the voltage proportional to the average value of the voltage at the output of the amplitude-pulse modulator; UGN is the voltage at the output of the reference frequency generator 13; U is the voltage at the output of the averaging filter 9; Us is the voltage at the output of the integrator 11; Ug is the voltage at the output of D-flip-flop 12; Un is the trigger voltage of the D flip-flop.

The device works as follows.

The first factor in the form of a voltage Ui (Fig. 2 a) is fed to the information input of the first pulse-width modulator 3, and the second factor as voltage 1) 2 - to the information inputs of the first pulse-amplitude modulator 2 ,

The input voltage of the reference voltage of the pulse-width modulator 3 receives the reference voltage Uz (Fig. 2a) of a triangular shape from the output of the generator 4. At the output of the pulse-width modulator 3, a pulse-width modulated voltage U4 is formed (Fig. 2 b) with a constant amplitude and pulse duration proportional to the voltage UL

Supposing that it does not have time to change significantly during the time tj and t2, since the frequency f0 of generator 4 is unchanged and is chosen much higher than the frequency of change of voltage Ui, we obtain the conversion function in the form

t1-t2 U1 (1)

t1 + t2 Am

For the case of negative polarity of voltage Ui, the relation ti -t2 Ui Am

time interval

(2)

t + t2

The relative (ti -12) is directly proportional to the voltage Ui of both polarities, and in the expression of the conversion function the stability of the conversion coefficient is determined only by the stability of the amplitude of the voltage of a triangular shape,

Next, the pulses U4 arrive at the control input of the first amplitude-pulse modulator 2. At the output of the amplitude-pulse modulator 2, a voltage is formed from (Fig. 2 V) in the form of opposite-polarity pulses whose duration in terms of shape and form, the modulating voltage U2.

Assuming that the voltage U2 does not have time to change significantly during the time ti and t2, we find that the average for the interval (ti + t2) voltage at the output of the amplitude-pulse modulator 2 is determined by the expression

U6 U2 --- U2- t2 U2

ti

ti + t2

t2

ti + t2

(3)

(four)

t + t2

and in proportion to the product of the stresses Ui and U2:

U6 -.

Am

i.e., the multiplication precision of the input signals Ui and U2 depends on the instability of the amplitude of the triangular voltage, which is especially noticeable in the transformations of low level voltages.

The latitude and amplitude modulated voltage Us is fed to the first input of summing integrator 11 covered by a pulse feedback.

Pulse feedback in integrator 11 is performed via a D-flip-flop 12.

The voltage Us has the form of short bipolar pulses, but its average value changes relatively slowly, so the constant component of the pulse signal Us, defined by expression (4), is subjected to conversion, and

fast changes are averaged by integrating properties of the integrator 11.

Under the action of the voltage Ue, the output voltage of the integrator 11 increases (FIG. 2). After the voltage Us is over, at the information input of the trigger trigger threshold Urt at this input on the lower leading edge of the pulse emitted by the oscillator 13 of the reference frequency, the trigger 12 switches and the output of the logical unit, under the influence of which the key 10 closes, when connected to the second input of the integrator 11, the voltage U with ayhodz of the averaging filter 9, which is opposite to the sign of the voltage Ue. The voltage at the output of the integrator Ug decreases. At the end of the clock generator period, the trigger 12 returns to its original state, i.e. when the next pulse arrives, the D-flip-flop 12 is thrown to the zero state and the key 10 is opened.

The cycle is periodically repeated.

Considering the average for the period of conversion the current of the integrator 11 is equal to zero, we get

Ue TVy ... U T0 p, g.

  0

or

UiU2

Your u that

Am

from which it follows that IHU2

f

oh

fo.

(6)

(7)

Am U7 where r is the constant of integrator time 11;

fo and To - output frequency and period of the signal generator 13 reference frequency;

fsbix and yours - output frequency and period of the D-flip-flop 12.

Using the output of the expression for the voltage U from the output of the averaging filter 9 the same relations as in the output voltage Ue, we obtain

and -7G

Am

where uo is the value of the reference voltage source 5.

The width and amplitude modulated signal from the output of the second pulse width modulator 7 with a constant amplitude equal to the value of the reference voltage Uo and a duration determined by the instability of the amplitude of the voltage of a triangular shape, is fed to the input of the averaging filter 9, at the output of which I form a continuous signal in the form of voltages and (fig. 2 e).

In view of the expression, it can be written as

.UlU2

1 OUT;

U2o

fo,

those. the output frequency of the D-flip-flop 12 is proportional to the product of the INPUTS. voltage and does not depend on the amplitude of the reference voltage of a triangular shape, which provides the possibility of high accuracy of conversion due to the elimination of the error component associated with the instability of the amplitude of the voltage of a triangular shape,

Claims (1)

Invention Formula thirty 40 45 50 55 20 25 The time pulse multiplying device contains the source of the reference voltage, the first pulse-width modulator, whose information input is the input of the first factor of the device, and the output is connected to the control input of the first pulse-amplitude modulator, the first information input of which is the second multiply, - the device bodies, and the output of the first amplitude-pulse modulator is connected to the first input of the summing integrator, the output of which is connected to the information input of the D-flip-flop, the output to Secondly, it is the output of the device and is connected to the control input of the key, the output of which is connected to the second input of the integrating 3 ° integrator, the clock input of the D-flip-flop is connected to the output of the reference frequency generator, characterized in that The first and second inverters, a triangular voltage generator, a second pulse-amplitude modulator, a second pulse-width modulator, and an averaging filter are introduced, the input of the second device factor being connected through the first inverter with the second information input of the first amplitude-pulse modulator, the output of the reference voltage source is connected to the first information input of the second amplitude-pulse modulator, to the information input of the second pulse-width modulator and the second inverter to the second information input of the second amplitude-pulse the modulator, the output of which is connected via an averaging filter to the information input of the key, the output of the second pulse-width modulator is connected to the control input of the second amplitude of the pulse-modulated module, the output of the voltage generator of the triangular voltage of the first and second width-shape is connected to the inputs of the reference pulse modulators, but T