SU783716A1 - Digital modulometer - Google Patents

Description

The invention relates to a radio metering technique and can: be used to accurately measure the depth coefficient of amplitude modulation (AM) with a sinusoidal shape of the high frequency signal envelope. A digital modlometer is known, which contains an input block, a transforming analogue-code, a digital comparison block; synchronization unit, control unit, two reversible counters, digital readout unit, logarithmic chains, operational amplifier 1. The disadvantages of this device are hardware complexity and low accuracy. Closest to the present invention is a digital modlometer comprising an input unit, a linear detector, an amplitude detector with a closed input, a low-pass filter, and a G2 splitter unit. Its disadvantage is low measurement accuracy. In order to increase the accuracy, a digital modlometer containing serially connected input unit, a linear detector, an amplitude detector with a closed input, a voltage-frequency converter, and a low-pass filter connected between the output of the linear detector and another input of the voltage converter is a frequency, and a digital readout unit with an automatic control unit, equipped with a reversible pulse counter, as well as a serially connected key that stores DC / DC converter, voltage divider, total difference unit, switch and switch, the other input of which is the device input and the output connected to the input unit, the output of the frequency converter connected to the input of the reversible counter, one output of which connected to a digital reading unit and the other to a voltage divider, the key input connected to the output of the low-pass filter, and the output of the DC / AC converter connected to another input one total difference block. The drawing shows the block diagram of the proposed digital modlometer. The modlometer contains a switch 1, an input unit 2, a linear detector

3, and a closed-loop detector 4 with a closed input, a voltage-frequency converter 5, a low-pass filter, a reversible pulse counter 7, a digital reading unit 8 with automatic control, a key 9, a storage unit 10, a constant-voltage converter 11, the output of which is connected to the input of the voltage divider 12, and to the first input of the sum-differential unit 13, the outputs of which are connected to the inputs of the switch 14.

Digital modlometer works in two cycles.

In the first measurement cycle, using the amplitude detector from the voltage and, (t), the amplitude value of the envelope of the modulating voltage and constant voltage (ii) is applied to the first input of the converter 5. The voltage U (t) is constant This component U with the help of low-pass filter 6, which is fed to the second input of converter 5, the latter divides the voltages U and U, and their quotient as the number of pulses goes to the summing input of the reversing counter 7 pulses for a fixed time T, ass It is received by the automatic control unit of block 8. The resulting number of pulses N is a rough measurement result.

At the output of the switch 14, an amplitude modulated voltage DO (t) is formed.

In the second measurement cycle, key 9 is open. In this case, the voltage UQ (t) is transformed in the same way as in the first cycle. In counter 7, the number of pulses Nrj is recorded, which is proportional to the AM coefficient of voltage Uo (t). The measurement result to be indicated is determined by the formula

N,

2N.

N

Formula of Invention

A digital modlometer containing a series-connected input unit, a linear detector, an amplitude detector with a closed input, a voltage-frequency converter, and a low-pass filter connected between the output of the linear detector and another voltage converter - deactivator, and a digital reading unit with automatic control It is distinguished by the fact that, in order to increase accuracy, it is equipped with a reversible pulse counter, as well as a series-connected key, a storage unit, a converter variable voltage, voltage divider, sum-transmitting unit, switch and switch, the other input of which is the device input and the output connected to the input unit, the output of the frequency converter voltage connected to the input of the reversible counter, one output of which is connected to the digital reading unit and the other with a voltage divider,

the key input is connected to the output of the Low-pass Filter, and the output of the DC / DC converter is connected to another input of the sum-difference unit.

Information sources,

taken into account in the examination

1. USSR author's certificate 347694, cl. G 01 R 29/06, 1975.

2. US patent 3990011, cl. 324-119, 1974.

Claims (1)

Claim A digital modulometer containing an input unit, a linear detector, an amplitude detector with a closed input, a voltage-frequency converter, and a low-pass filter connected between the output of the linear detector and another voltage-frequency converter cocking in series, and a digital reading unit with an automatic control unit, It is characterized by the fact that, in order to increase accuracy, it is equipped with a reversible pulse counter, as well as serially connected by a key, a storage unit, and a constant current converter about voltage to ac, voltage divider, sum-difference block, switch and switch, the other input of which is the input of the device, and the output is connected to the input unit, the output of the frequency-voltage converter being connected to the input of the reversible counter, one output of which is connected to a digital reading unit, and the other - with a voltage divider, the key input is connected to the output of the Low-Pass Filter, and the output of the DC / AC converter is connected to another input of the sum-difference block.