SU1649573A1 - Functional transducer - Google Patents

Abstract

The invention relates to analog computing, a technique for generating and converting signals, a measuring technique and can be used in function generators, frequency modulators, frequency voltage converters with a sinusoidal output. The aim of the invention is to simplify the converter and increase accuracy. The converter contains two bipolar transistors of the same conductivity type, a load resistor, two correction resistors, and a voltage divider made on the resistors. Balancing the output sinusoidal voltage to minimize the harmonic coefficient is done by finely setting the triangular input voltage level, carefully balancing it in the triangular voltage generator and slightly offsetting the zero level in the generator or decoupling amplifier, and adjusting the magnitude of the load resistor and correcting resistors. 1 il. SS (L

Description

The invention relates to analog computing, a technique for generating and converting signals, a measuring technique, and can be used in functional generators, frequency modulators, voltage-frequency converters with a sinusoidal output.

The aim of the invention is to simplify the converter and increase accuracy.

The drawing shows a diagram of the functional Converter.

The converter contains two bipolar transistors 1 and 2 of the same type of conductivity, a load resistor 3, two correction resistors 4 and 5, a voltage divider made on the first 6 and second 7 resistors, input 8 and output 9 transducers.

The Converter operates as follows.

The input 8 is supplied with a symmetrically triangular voltage with an amplitude of 5.5-10 V, the frequency of which varies

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wide range, and the amplitude is constant. At low voltage levels, the transistors 1 and 2 are closed, and the output voltage is equal to the input voltage. Due to this, the formation of the initial - linear part of the sinusoid is provided. As the input voltage level rises, one of the transistors, for example, transistor 1, opens at a positive half-wave of the input voltage. The base voltage divider formed by resistors 6 and 7 creates the potential at the bases necessary to open the transistors. The collector junction of the transistor 2, turned on in the inverse direction with a positive voltage half-wave, shunts the emitter junction of the working transistor 1 and compensates for temperature changes in its input characteristic. The smooth opening of transistor 1 leads to a violation of the linear relationship between the input and output voltages and ensures the formation of the middle part of the sinusoid. The emitter current of transistor 2, due to the effect of the inverse transmission from its collector circuit, is small compared to the collector current of transistor 1 operating in normal mode. The circuit in this area has a collector thermal stabilization performed by the load resistors and the base portion of the hep. Voltage. which further reduces ce temperature instability.

At high levels of the input signal, an avalanche breakdown occurs in the emitter junction of transistor 2, as a result of which the base current of transistor 1 increases dramatically, and its collector current increases accordingly. In this mode, the circuit operates as a parallel amplitude limiter, the output voltage remains almost unchanged with an increase in the input signal level, which allows forming the top of a sinusoid without distortion. In this region, the TKN of the emitter junction of the transistor 2, which is in the avalanche sample state, and the TKN of the junction transition of the transistor 1, which is connected in the forward direction, is completely compensated, thereby ensuring low temperature instability of the ampli

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amplitudes of the generated oscillations and harmonic coefficient.

When the polarity of the input voltage changes, the transistors change roles. Correction resistors 4 and 5 are designed to reduce the influence of the spread of the input characteristics of the transistors, their value is set to the minimum of even harmonics in the output voltage. The optimal value of the load resistor 3 depends on the type of transistors selected, their current gain factors, and the resistance of the resistors 6 and 7 of the base voltage divider. Its exact value is determined by the minimum harmonic coefficient.

Balancing the output sinusoidal voltage Minimizing the harmonic coefficient is done by finely setting the input voltage level of a triangular shape, carefully balancing it in a triangular voltage generator and slightly shifting the zero level in the generator or decoupling amplifier, and also adjusting the value of the load resistor and correcting resistors.

Claims (1)

Invention Formula A functional converter containing a load resistor, two bipolar transistors of the same type of conductivity, the bases of which are combined, a voltage divider made on the first and second resistors, and two correcting resistors, and so that in order to simplify the converter and increase the accuracy, the bases of the first and second bipolar transistors in it are connected to the middle terminal of a voltage divider, the free terminal of the first resistor of which is connected to the converter output, the first terminal is a resistor load, the emitter of the second bipolar transistor and through the first correction resistor is connected to the collector of the first bipolar transistor, the emitter of which is connected to the zero potential bus, the free output of the second resistor of the voltage divider, and through the second correction resistor is connected to the collector of the second bit transistor, The second terminal of the load resistor is connected to the information input of the converter. entrance treug. but