SU1226351A1 - Apparatus for measuring depth of modulation - Google Patents

Abstract

The invention relates to a radio measuring technique and can be used in automatic control systems with amplitude modulated effects. The purpose of the invention is to increase speed. The device contains a controlled voltage divider 1, a linear detector 2, a normalization unit 3, an operational amplifier 4, a differentiation unit 5, a limiter-driver 6, a comparator 7, a comparison unit 8, a digital display register 9, a summation counter 10 and a converter 11 code -purpose. An introduction to the device of a linear detector, an operational amplifier, a differentiation unit, a comparator, a comparison unit, a register with digital indication, a code-voltage converter, and the formation of new connections between the elements of the device allows measurement and indication of the modulation coefficient in each period of the modulating oscillations and eliminate the dependence of speed on the magnitude of the modulation depth of the original signal and the degree of measurement accuracy. 1 il. (L yu o5 oo sd

Description

I

The invention relates to radio frequency engineering and can be used in automatic control systems with amplitude modulated effects, -

The purpose of the invention is to increase the speed by measuring and displaying the modulation coefficient in each period of modulation to oscillate and eliminate the dependence of speed on the magnitude of the modulation depth of the original signal and the degree of measurement accuracy,

The drawing shows the block-modem device.

The device contains a controlled voltage divider 1, a linear detector 2, a block 3 of rating J, an operational amplifier 4, a block 5 of differentiation, a limiter-former 6j comparator 7, a block 8 compared to 9 register 9 with a digital display counter 10 summation, converter The 11th code is a voltage, the output of the controlled voltage divider 1 is connected to the input of the linear detector 2, the direct output of which is connected to the input of the summation counter 10 through successive coefficients shaper-generator 6 and the comparison unit 8, with control The digital inputs of the register 9 with digital indication and the summation counter 10 through serially connected differentiation unit 5 and comparator 75 with the second input of controlled voltage divider 1 through serially connected operational amplifier 4 and normalization unit 3, the inverting input of operational amplifier 4 connected to the capacitive linear detector 2, and the output is also connected to the second input of the limiter-former 6, the outputs of the totalizer counter 10 are connected to the inputs of the register 9 with a digital indication and the converter code 11 is a voltage, the output of the latter is connected to the second input of the comparison unit 8.

The device works as follows:

On. input of controlled voltage divider 1; amplitude-modulated signal applied

U (t) V, (1 + msin it) sin (cot + Cfo), (1)

where Uz is the amplitude of the carrier oscillation;

initial carrier phase; circular h & modulating-harmonic signal, with modulation depth factor

m -

Ataks VH

(2)

As can be seen from expression (2), by lowering the normalization to a certain standard value, the process of measuring the modulation depth coefficient is greatly simplified.

The input voltages of the linear detector 2, taken from the direct and capacitive outputs, are respectively supplied to the non-inverting and inverting - inputs of the operational amplifier 4, with a unit transfer ratio of 5; the amplitude of the output signal will correspond to the amplitude of the carrier oscillation V. Standardization U is carried out by changing the dividing ratio of the controlled voltage divider 1 under the action of the control signal from the output of the normalization unit 3.

At the output of the limiter -formati- ry sh 6, the positive creep of the envelope of the amplitude-modulated oscillation is formed, which is then fed to the input of the comparison unit 8. If the generated signal reaches the response level of the comparator block 8, then it triggers and generates a pulse, which is recorded in the summation counter 10, which, in turn, leads

an increase in the output voltage of the converter 11 by one level, the code is the voltage, and consequently, the response level of the comparison unit 8. With a further increase in the input signal, the operation of the device is similar, with the output signal of differentiation unit 5 repeating the input signal taken from the direct output of the linear

detector 2, taking into account the transfer characteristics of the differentiation unit 5. At the moment of changing the sign of the derivative from positive to negative (transition of the derivative through

zero), t, e at the moment when the output signal reaches the limiter-formatter 6 of the extreme 3 1s, a pulse is generated at the output of the comparator 7, allowing the code to be rewritten from counter 10 to register 9 and the counter 10 is reset.

Claims (1)

Invention Formula A device for measuring the modulation depth, comprising a summation counter, a limiter-former, a controlled voltage divider, a normalization unit, the output of which is connected to the second input of a controlled voltage divider, in order to increase the speed a linear detector, an operational amplifier J, a differentiation unit, a comparator, a comparison unit, a register with a digital indication, a converter code - voltage, and the output of the controlled voltage divider is connected to the input of the linear detector, the capacitive output of which is connected to the input of the summation counter via serially connected limiter driver and comparison unit, with control inputs of the register with digital indication and summation counter through serially connected differentiation unit and comparator, with the input of the rationing unit and the second input of the limiter -former - through an operational amplifier, the non-inerting input of which is connected to the direct 4 output ohm of the linear detector, the outputs of the csgmming counter are connected to the inputs of the register with digital indication and the code-voltage converter, the output of the latter is connected to the second input of the comparison unit.