SU679944A1 - Frequency characteristics analyzer - Google Patents

Description

The invention relates to the field of automation, information computing and measuring equipment, in particular, to devices for experimental instrumentation, the frequency characteristics of dynamic objects. The known frequency analyzer {in 1x characteristics contains a harmonic test signal generator, the output of which is connected to the system under study, an op driver (functions, two multiplying devices, for the first time the KCfTopbix inputs are connected to the outputs of the on-chip functions, and the second input receives a reaction signal from the system under study on the test signal, two HHrerpaTqpa, whose inputs are connected to the outputs of multiplying devices. With the help of integrators, the signals of the product are integrated in such a way phase and quadrature components of the signal of the reaction system on the test harmonic effect t1. The disadvantage of this analyzer is the low measurement accuracy. Of the known frequency response analyzers, the ternstic is closest to the invention to the technical essence is the analyzer containing the test signal generator, the output of which is connected with the output of the analyzer, two multiplication units, the first inputs of which are associated with the corresponding outputs of the driver of the reference signals, the input of which is connected to the first output b Control with the second output of which are connected the control inputs of two integrators, the input of the first of which is connected to the output of the first multiplication unit 2. The disadvantage of this frequency analyzer is the low resolution of the presence of a constant component in the system response to the test harmonic impact. By permitting, hereinafter, we mean the maximum possible ratio of the obtained values of the in-phase and quadrature components. The reason for this drawback is the lack of matching the dynamic ranges of the analyzer of the measured (signal. The purpose of this invention is to increase the accuracy of the analyzer. This goal is achieved in that the frequency analyzer contains sequentially connected memory block and code-analog converter, switch and serially connected block comparison, attenuator pfog block and forms (the code of the range code, the output of which is connected to the control input of the attenuator, the output of which is associated with the second inputs of the multiplication units; And the first input of the switch, the second input of which is connected to the output of the second L multiplication unit, to the control input, the third output of the control unit, and the output to the input of the second integrator, the output of which is connected to the input of the memory unit, the output of the converter code - the analog is connected to the first input of the comparator unit, the second input of which is connected to the analyzer input, the fourth output of the control unit is connected to the control inputs of the memory unit and the range code generator, the fifth output is connected to the generator input tovyh signals as input - to the output of the threshold unit. The drawing shows a block diagram of the analyzer frequency characteristics. It contains a code converter - analog 1, memory 2, system under study 3, comparison block 4, attenuator 5, threshold block 6, range code generator 7, test signal generator 8, multiplication unit 9, integrators 10 and 11, reference signal generator 1 , multiplication unit 13, switch 14 (switch positions I and I) control unit 15. The analyzer operates as follows. On the signal Setting zero, controllable by control unit 15, integrators 10 and 11 and memory 2 are set to zero, shaper code 7 is in the state corresponding to the maximum sensitivity of attenuator 5, switch 14 is set to position I. At the output of the converter, code - analogue 1, a zero potential is formed and is fed to the input of the comparator unit 4. The analyzer is in the state of measuring the constant component of the signal arriving at the other input of the comparator unit 4. By the signal Start of measurement the measurement generated by the control unit 15, the computation of the integral of the integral 10 begins with the help of the integrator 10

 1., - Ju (t) -dt,

where U (t) is the output signal of the attenuator 5, which corresponds to the response of the system to

l

Ij -JUCtKqsouidt,

 about

Claims (2)

where sin ш t, Bos (jUt are the signals of the reference functions of the generator of the test signal generator 8 and is the sum of the constant and variable components: Using an attenuator 5, threshold unit 6, the former 7, the range code coordinates the dynamic range of the response signal If the output signal of the attenuator 5 exceeds the dynamic range of the analyzer, then the threshold unit 6 is activated, while the control unit 15 receives a signal Pr measuring the measurement, at the output of the range code generator 7, a code corresponding to the lower sensitivity of the controlled attenuator 5 is formed, the control unit 15 interrupts the calculation of the integral Jj, sets the integrator 10 to zero and generates a measurement signal Jj. matching the dynamic ranges of the response signal of the system and the analyzer is repeated until, during one period of change, the variable component of the output response signal This signal of attenuator 5 will not exceed the dynamic range of the analyzer, while the control unit 15 generates a signal. The end of the measurement and the integrator contains the integral -Ij corresponding to the constant component of the response signal of the system under study 3. At the command of the control unit 15, the contents of the integrator 10 are recorded in the unit memory 2 and the code converter — analogue 1 produces a voltage equal to the constant value of the response of the system, which is fed to the subtracting input of the comparator unit 4. At the output of the unit, 4, a signal appears that is equal to the variable component of the reaction of the system under study 3. When this switch 14 is turned to position II, the device enters the measurement state of the in-phase and quadrature components of the reaction of system 3, the contents of the integrators 10 and 11 turn to zero, The shaper 7 of the range code enters the state corresponding to the maximum sensitivity of the attenuator 5. Next, the phasing unit 15 generates a signal to start the measurement and the calculation of the integrators begins: -Ig Y jua 3inijyi dt), do Suitable for multiplying units 9 and 13 with the reference signal generator 12. Using an attenuator 5, a threshold unit 6, a shaper code generator 7, the dynamic ranges of the signal of the system 3 and the analyzer are matched. This process proceeds in a manner similar to the process described above for matching the dynamic range of the entire signal and the dynamic range of the analyzer. If during the period of variation of the variable component of the measured signal the amplitude of the output signal of the attenuator 5 does not exceed the analytic range of the analyzer, the control unit 15 forms the command End of Measurement, the calculation of the integrals Jj and. the contents of the integrators 10 and 11 correspond to the in-phase and quadrature components of the response signal of the object under study 3. The described frequency response analyzer allows you to increase the resolution of the presence of a constant component in the response signal of the system 3 to the test harmonic effect, since during the first of the measurement cycle, the constant component of the response signal of the system 3 under investigation is calculated and compensated during the second measurement cycle (calculation of the in-phase and quadrature with leaving the response signal) with the help of threshold block 6, generator 7 of the range code, attenuator 5, comparison block 4, the dynamic ranges of the response signal of the system 3 and analyzer are optimally matched, which ensures the maximum resolution of the analyzer. Using the automatic range and constant compensation system frees the operator from the need to use a priori information about the measured signal (dynamic range and constant component value) to manually select the sensitivity of the analyzer and compensate for the constant component. This is especially important for signals in the infra-low-frequency domain, where obtaining this information is time consuming or impossible. Claims of the Frequency Characteristic Analyzer comprising a test signal generator, the output of which is connected to the analyzer output, two multiplication units, the first inputs of which are connected to the corresponding outputs of the reference signal generator, the input of which is connected to the first output of the control unit, the second output of which is connected The two inputs of the two integrators, the input of the first W of which is connected to the output of the first multiplication unit, are denoted by the fact that, in order to increase the accuracy of the analyzer, it contains The interconnected memory block and the converter code are analog, a switch and a serially connected comparison block, an attenuator, a threshold block and a shaper code generator, the output of which is connected to the attenuator control input, the output of which is connected to the second inputs of the multiplication blocks and the first input of the switch, The second input of which is connected to the output of the second, b;) eye of the multiplication, with the control input is the third output of the control unit, and with the output input of the second integrator, the output of which is connected to the input of the memory unit, output eugenizer code - the analog is connected to the first input of the comparator unit, the second input of which is connected to the analyzer input, the fourth output of the control unit is connected to the control inputs of the memory unit and the range code generator, the output output to the input of the test signals generator, and the input to corresponding output of the threshold block. Sources of information taken into account in the examination 1.Patent UK No. 1074624, cl. G 01 R 27/28, 1965. 2. USSR author's certificate number 199535, cl. G 05 B 23/00, 1967.