SU866564A1 - Device for raising to the power of width-modulated signals - Google Patents

Description

(54) DEVICE FOR EXPOSURE TO THE DEGREE. BROADLY MODULATED SIGNALS

one

The invention relates to computing and can be used in automatic control and control devices, in information measuring systems and devices where information is prevalent. type of width-modulated signals (PWM-signals) -. A device that performs multiplication, division, and raising to a positive integer using a bridge circuit is known.

The device consists of a balancing bridge, the three arms of which are series-connected cells and a scale resistor, and the fourth is a group of scale and pulse-controlled resistors, the first and fourth, second and third shoulders of the bridge being connected by common points to the source of the reference voltage, and the common points of the first and second, third, and fourth shoulders are connected to the comparison inputs of the differential operational amplifiers of the direct current and through the averaging capacitors to the common point of the circuit. The output of the amplifier is connected to the input of a pulse-width modulator, the output of which is the output of the device and connected to the control inputs of the pulse-control resistors of the quadruple arm of bridge 1.

However, the device has a low accuracy due to the presence of methodical error of approximation. .

The closest in technical essence is a device that contains the first equilibrating 0 with a bridge with a DC voltage source in the supply diagonal and four pulse-controlled resistors in the shoulders, the outputs of the measuring diagonal of the bridge are connected to the zero potential bus and to the comparison inputs of the first differential amplifier connected by an output to the input of a pulse-width modulator, output: od

20 of which is connected to the control input of a pulse-controlled resistance current in the third shoulder of the bridge and is the output of the device, as well as the second balancing bridge, to the diagonal

25 of which is connected to the output of the second differential amplifier, and its shoulders are included in the pulse-controlled resistors, the inputs of the second. the amplifier is included in another diagonal 30 of the second bridge 2.

The disadvantages of the known device are limited functionality, which is reflected in the inability to reproduce the whole negative degree of the input function.

The purpose of the invention is to extend the functionality by calculating the whole negative degree of the input function.

The goal is achieved by the fact that a device for raising to the power of width-modulated signals, containing two bridges, a source of reference voltage included in the diagonal of the power supply of the first bridge, between the common pins of the first and third, as well as the second and fourth arms, the bridge, the common pin of the second and fourth the fourth shoulders is connected to the zero potential bus, the first and second pulse-controlled resistors, forming the first and fourth shoulders of the first bridge, the third and fourth pulse-controlled resistors, respectively, The first and second shoulders of the second bridge, the fourth shoulder of both bridges, respectively, are common, two differential amplifiers whose inputs are connected to the measuring diagonal of the corresponding bridge, the output of the first differential amplifier is connected to the first output of the device and the control to the first differential amplifier dim the input of the second-pulse-controlled resistor, three smoothing air conditioners, connected respectively parallel to the second shoulder of the first bridge, the second shoulder of the second bridge IJ quarter The bridge arm contains a second pulse width modulator and two current supply resistors, the first of which is the second shoulder of the first bridge, and the second one is the common third shoulder of the first and second bridges, the output of the first pulse width modulator is connected to the control input of the third pulse-controlled a resistor, the output of the second differential amplifier is connected via a second pulse-width modulator to the second output of the device and to a control input of the fourth pulse-controlled resistor.

The black diagram shows the block diagram of the proposed device.

The device contains a source 1, a constant voltage, pulse-controlled resistors 2 and 3, current-conducting resistors 4 and 5, pulse-controlled resistors 6 and 7, differential amplifiers 8 and 9, pulse-width modulator 10 and 11, smoothing capacitors 12 - 14.

The device works as follows, with

On the control input of a pulse-controlled resistor 2, included

In the first shoulder of the first bridge, a PWM signal is received with a relative duration of periodically repeating S-square rectangles. In each of the periods T of the operation, the impedance of the pulsed-controlled resistor is closed for the time V and open for the time T = f (T / T). Its conductivity is, on average, proportional to the relative duration of a.,. Development: an alternating current of pulsed-controlled and fixed resistors is provided by smoothing capacitors 12-14. Thanks to them, the inputs of the differential amplifiers B and 9 receive only the constant components of the voltages at points a b, c, and the higher harmonics are suppressed.

The voltage difference at the points a and; G, isolated and amplified by the amplifier E, affects the pulse width modulator 10. The latter produces a PWM signal with a relative duration of.,. which, due to the negative feedback, acting on the pulse-controlled resistor 3, provides the balance of the first bridge.

(one)

14 G, G ,, G ,,, and

- average values of IV nor conductivities.

therefore

(2)

.Q

G9, G ,, 0, „G

Here G ,,

and

G-e.

IV

Similarly, from the condition of the balance of the bridge (2) given that

Gj Ge and G ,,,

G, G

III

get & a tt.

Here, G is the conductivity of the resistors of the connecting bridge arms. It is easy to see that in order to obtain the third and subsequent negative values of the input variable, it is not necessary to connect additional bridges to the device, connected in the same way.

To obtain positive integer powers of the input variable {it is necessary to send the input PWM signal directly to the first output of the device and to the control inputs of the pulse-controlled reenstors of the second bridge.

Technical and economic effect from. use of the invention is determined by the expansion of functional capabilities at low hardware costs and high manufacturability.

Claims (2)

1. Author, USSR certificate 590761, cl. G 06 G 7/16, 1976. 2. Authors certificate of the USSR 641459, cl. G 06 G 7/16, 1977 (prototype).,