SU771706A1 - Radio signal simulator - Google Patents

Description

The invention relates to devices designed to train operators, navigators working with equipment, to ensure safe driving of vehicles such as airplanes, ships, etc., which use radio navigation aids to determine the location of an object from received signals of radio navigation stations. systems like Laurent, Omega, etc. Reception and (processing) of signals in real conditions is hampered by numerous interfering factors: signal levels change, noise level changes (fluctuation, narrowband sinusoidal, and pulse), scattering signals appear, fluctuating signals, the shape of signals, their amplitude, phase relations between spectral components, etc. It is rather difficult to organize the training of navigator operators to work with equipment in real conditions, taking into account all the variety of interfering factors. Therefore, operator training in receiving equipment, as well as quality control of equipment under conditions close to real, is carried out using radio signaling simulators, allowing you to recreate situations that are typical of actual signal reception conditions in training conditions. When training and simulating crews, it is especially important to provide an imitation of the most difficult working conditions with equipment. One of such conditions for real objects, such as airplanes, ships and other vehicles, is a changing interference environment: the level of fluctuation interference, the level of narrowband spectrum-centered noise, etc., changes. The operator in such changes should ensure the operation of the radio navigation equipment. When a narrowband interference gets into the spectrum of a received signal, the operator must provide suppression up to a certain level of this interference, for example, using a tunable notch filter. Obviously, the accuracy of the equipment in this case depends on the correctness of the operator's actions. Therefore, in order to increase the effectiveness of crew training, improve the control of equipment operation and the correctness of operator actions, it is necessary to simulate interference situations and control operator actions or equipment operation under specified conditions. Radio signal simulators are known that contain a master oscillator, frequency converters, for example, in the form of dividers, multipliers, etc., ensuring the formation of signals of given frequencies, phase switches, signal attenuators. They are built on elements of various types. Nowadays, devices that are fully implemented on digital logic elements are widely used. They can be both autonomous and non-autonomous devices based on digital computers. Such devices allow microminiaturization, allow you to generate output signals of different frequencies with variable parameters (frequency, amplitude, phase, etc.). When using digital reception methods characterized by the absence of automatic control circuits of sipgal signals in the receiving equipment and severe restriction of received signals in the receiving part / it is difficult for the operator to recognize the narrowband signals on the jjkk signal, because the signals have a pulse signal at the output of the receiving part of the equipment shape and normalized in amplitude. Therefore, even with an oscillographic indicator, it is almost impossible for the operator to estimate the ratio of the amplitudes of the useful and interfering signals and. Based on the evaluation results, turn on the noise suppressor and adjust it so as to maximally suppress the interference signal. It also turns out to be difficult to control the operation of automatic interference suppressors present in the equipment. In both cases, the lack of objective data on the degree of signal rejection is a drawback. This makes it difficult to objectively adjust the actions of the operator in the process of learning how to work with the receiving equipment, to which a signal is fed that simulates a real signal. The verification of automated receiving systems is also difficult. The basic measurement results of the useful signal meter pairs are difficult, since measurement errors have a number of components, masking components caused by an interfering signal. This deficiency leads to a decrease in the efficiency of operator training and to an increase in training training sticks, as well as to a prolongation of the testing time of equipment, which leads to an increase in costs and training and. condition monitoring. paraparaty. This disadvantage is aggravated by the fact that the gain of receivers with extreme limitation of signals has a significant variation from sample to sample, which makes it almost impossible to install single conditions (simulated signal napimeters) that are most suitable for these modes of operation. when using well-known signal simulators. The closest to the invention is a radio signal simulator | j2j containing a master oscillator, a driver of the main simulated signal, a driver of an additional simulated signal, a block for specifying the amplitude ratio of the main, an additional signal / output block to which the device under test is attached, a signal parameter meter and a ratio meter the amplitudes of the primary and secondary signals connected to the device under test, the control unit. In this device, two signals of close frequencies are formed, the amplitudes of their amplitudes are set, the signals are measured on the device under test with which the learner works (test the operator, the ratio of the same signals on the output of the device under test is measured by the ratio meter; by changing the ratio of signal levels, it is possible to judge the condition of the device under test and the correctness of the operator’s actions during the work with the device under test. The gain of the device under test, its spread also does not affect the effectiveness of the test. The disadvantages of this device are that all simulated signals (for example, two - main and additional) must lie in the limited bandwidth of the test receiver. As a result, the frequencies of the test signals, the level ratio of which is set and then measured, are close. To measure the ratio of the amplitudes of the signals, they must be separated, which at relatively close frequencies is difficult. Each signal must be selected by a highly selective filter with a narrow bandwidth. Filters are quite complicated to manufacture and configure, their parameters change as environmental conditions change. Rebuilding such filters

difficult, and in a number of cases it is almost impossible. This prevents the frequencies of simulated signals from changing within the operating range. Thus, the implementation of the devices is difficult, and due to the south imitation of signals with varying parameters is reduced. Since the possibilities of simulating signals with variable parameters are limited, the efficiency of training operators to work in difficult conditions for receiving signals with varying parameters is also reduced.

 The aim of the invention is to improve the accuracy of imitation by providing imitation and control of signal parameters with nepeMeHHHN K parameters ofHHMitiiMH parameters, which expands the fuzzing capabilities of devices and increases the efficiency of training and training of operators in conditions as close to real as possible.

This goal is achieved by the fact that a radio signal simulator containing a master oscillator connected via a series switch on. Simulated signals shapers with a shaper of signal levels, which are connected via serially connected matching unit and a shaper of real-life signals to the measuring parameters of signals and ratio of parameters, and a control unit connected to the shaper of their signals and signal levels, the shaper of auxiliary signals, connected to a master oscillator and a control unit, and a unit for changing the phase of auxiliary signals, connected to a signal generator The auxiliary process and auxiliary signals and to the parameter ratio meter, the auxiliary signal phase changing block containing a series-connected phase splitter, a phase discriminator, an integrator and a voltage level meter, an auxiliary signal generator comprising a series-connected discrete phase shifter and a frequency divider; the discrete phase shifter has serially connected the prohibition element, the OR element and the frequency divider, and the ratio of the parameters of soda Laughs sequentially included phase discriminator, integrator and threshold unit

FIG. 1 shows a functional diagram of the proposed device; in fig. 2 - option discrete phase shifter.

The device includes a clock generator 1, shaper 2 and 3 simulated signals, shaper 4 signal levels, matching unit 5, shaper b of actual process signals, mz 6 rapper 7 signal parameters, meter I parameter ratios, block 9 controls, shaper 10 vspogogelnyh signals , discrete phase shifter 11, frequency divider 12, a block 13 for changing the phase of auxiliary signals, a phase splitter 14, a phase discriminator 15, an integrator 16, a voltage level meter 17, a phase discriminator 18, an integrato R

0 19, threshold block 20.

Discrete. Lazrovatel, option which is shown on Leagues. 2 includes a frequency divider 21, a prohibition element 22, and an OR element, 23.

five

The radio signal migrator operates as follows.

C; .cwd} 0 dego of generator 1 is fed to the forerunner 2,3 and: the titled -5th signals are different ;: frequencies,

0, these signals are applied to the required ratio, for example 5: 1, of the signal levels; After that, the signals arrive at the agreement unit.

five

5 where they are mixed - in this

The same block, for example: EP, with the help of an attenuator, sets the level of output signals required by the generator to operate 6 real-process signals. The resulting complex signal is sent to the driver.

6, on which the viewer works. The operator, benefiting the authorities of the device, produces a casting noise suppression - ;;; so that the maximum degree of attenuation is greater in level 1: the signal to be held. In this case, if the parameters of the imaging unit 6 correspond to the requirements for HeNP / requirements, and the operator n) has correctly performed the tuning, then the larger amplitude of the signal is attenuated by some pas (for example, 25 times), i.e. at the output of the imager, the ratio of the signal levels changes with and becomes equal to 1: 5, instead of the ratio 5: 1. This change is captured by meter 8,

and meter 7 is used to measure the required signal parameters (al., temporal position, etc.).

The operating modes of the blocks are defined by the control block 9.

Meter 8 is built on the principle of synchronous detection. The phase discriminator 18 from the output of the imager b receives a mixture of two signals of different frequencies, the ratio of the amplitudes of which should be measured. One signal can be considered as useful, the second one as interference. To provide the synchronous detection mode of the useful signal to the second input of the phase discriminator 13, a signal is output from

five

phase splitter 14 of block 13. The frequency and phase of this signal are equal to the frequency and phase of the useful signal. As a result of the interaction in the discriminator 18 of two simulated and auxiliary (being in this case reference) signals, the sum of the signals at the output of the discriminator 18 is formed: the signal of the constant component is the result of the interaction; two signals (useful and reference) of one frequency with the same phases and a difference frequency signal, which is equal to the difference between the frequencies of the reference and the second of the edited signals. Both signals from the output of discriminator 18 are fed to integrator 19 with a large time constant, which plays the role of a filter. The signal of the steady state integrator 19 is not attenuated, and the differential difference signal is weaker the stronger, the higher the frequency of this signal and the longer the time constant of the integrator. So, for example, at frequencies of simulated signals of 102 and 101 kHz and the frequency of the auxiliary (reference) signal of 101 kHz, the integrator is executed as the simplest PC circuit with a constant time t of 0.1 s and element ratings of R 1 kΩ, C 10 μf signal the difference frequency of 1 kHz is attenuated by a factor of about 700 by comparison with the constant useful component of the signal. Thus, effective separation of the two frequency signals is accomplished without the use of complex Liltres. The output level of the phase discriminator 18 is determined only by the phase difference of the signals arriving at its outputs. To ensure this, with a high degree of accuracy, the input signal levels are normalized, for example, with noNKHUbra limiters in the discriminator input circuits. Limiting CHI levels is equivalent to using binary amplitude-quantized signals.

Thus, the phase discriminator 18 and the integrator 19 in this case are equivalent to a wideband limiter device — a narrowband filter with respect to a mixture of two signals — a useful one with zero carrier frequency (constant component) and an interference one with a difference frequency equal to the frequency difference between the two simulated signals. The ratio of the desired signal and the noise signal at the output of the imager b, if it is working properly and the operator is working properly, should be significantly less than one (in the given example, the ratio should be 1: 5, ie, 0.2). But it is known that the limiting filter system with signal ratios, noise less than 0.5, is linear and its output signal level is proportional to the signal-to-noise ratio at the device input. Thus, the output level is constant. integrator 19 with respect to the maximum level (taken as 1) is proportional to the ratio of two signals at the output of shaper 6. Due to this, block 20, together with elements 16, 19, measures the indicated ratio of the amplitudes of simulated signals at the shaper 6 output. The advantage of this structure of the meter 8 is noncriticality the input signal level, which is caused by the possibility of a rigid limitation of the signal at its input.

The stability and accuracy of the meter 8 is ensured only if the frequency and phase 0 of the auxiliary - reference signal arriving at the second input of the discriminator 18 are equal to the frequency and phase of one of the simulated signals. The frequency of the auxiliary signal, which is formed by the driver 10 from the signal of the master oscillator 1, is determined by the division factor of divider 12, which is chosen to be equal to the division factor of the analogous divider, which is part of one of the former 2, 3 simulated signals. However, the phase of the simulated signal changes during transmission through shapers 4 and 6. 5 Moreover, since shaper 4 and block 5 are part of their own simulator, the shift phases in them can be measured at a certain stage, and its value, being constant, will be known . But the phase shift, due to SIMM shaper 6, is unknown and can vary from sample to sample within wide limits. It also changes during the restructuring of the former 6 by the operator B during the operation. All this 5 makes it difficult to provide the operating mode required by the meter 8 in terms of the synphasicity of the signals supplied to the inputs of the discriminator 13.

In this device, the change of the phase of the auxiliary signal by the shaper 10 is carried out using a discrete phase shifter 11 connected at the input of the frequency divider 12. The control signal (control commands) of the phase shifter 11 is formed in block 13. The discriminator 15 of block 13 receives a signal from the output of the forlator b, and the second input of the discriminator 15 receives a signal from the output of the splitter 12 of the frequency former 10. Critic is fed through the phase splitter 14, in which i) op are two signals of the same frequency shifted by 0. ONE relative to the second by ninety degrees, i.e. squared.

One of them enters the discriminator 15, at the output of which a signal is generated with a zero difference frequency and a signal of the difference frequency equal to the frequency difference between the signals (in the example shown, 1 kHz). The zero difference frequency signal passes through the integrator 16 without attenuation, the second signal is attenuated by 2-3 orders of magnitude. The zero difference frequency signal filtered in this way is proportional to the cosine of the phase difference of the simulated and secondary signals having the same frequency. It is used as a control signal to adjust the phase of the Auxiliary signal of the forcer 1.0, the output signal of the integrator 16 is fed to the meter 17, where it is compared with the reference is the required (for example, zero) level. As a result of the comparison, the meter 17 generates a control signal supplied to the control inputs of the phase shifter. 11, the latter changes the phase of the auxiliary signal generated by the divider 12 until the error signal decreases to zero. After that, the signal of the phase separator 14, which arrives at the discriminator 15, is shifted in phase relative to the simulated signal of the same frequency coming from the generator 6, by ninety degrees, and the signal of the second output of the phase splitter 14, supplied by the NutNttJft to the input of the discriminator 18, is in phase with that the same signal from the imager b to the second input of the discriminator 13. Thus, regardless of the parameters and modes of operation of all units of the device, the simulated and auxiliary signals of the same frequency are fed to the meter 8, appear in the phase that. and is required to ensure its normal operation. In such a structure of blocks for the formation and control of parameters of simulated signals, a change in the frequencies of the signals does not require additional adjustment or reconfiguration of the selective circuits. The frequencies of the simulated main and auxiliary signals are changed by simply changing the division factors of the dividers 21 included in the generator 2, 3 and 10, which is easily accomplished with the help of logic circuits controlled by the signal from the control unit 9. the equality of the frequencies of one of the simulated and auxiliary signals is ensured automatically when setting equal division factors of the dividers-counters included in these drivers,

Thus, with the structure of the device and with the absence of adjustable elements, an operative change of the frequencies of the simulated signals, their separation and an objective control of the ratio of the amplitudes of the signals for any changes in the frequencies of the signals in the required range are provided. This allows testing the equipment, training the operators and constantly monitoring their actions in the most difficult conditions, which increases the effectiveness of the testing and training.

The 2,3 and 10 hraryT drivers should be built not only on the basis of frequency dividers, but also on the basis of any other frequency converters, for example, mixer mixers, frequency multipliers, etc., are not critical to the operation of the device as a whole. , only exact equality of frequencies of the auxiliary

0 and one of the simulated signals.

The implementation of other units of the device does not cause technical difficulties either. So, for example, discrete phase shifter 11 can be implemented on the basis of frequency divider 21, interdiction logic element 22 and logical OR 23. A periodic pulse signal from master oscillator 1 is supplied to the input of divider 21, and in divider 21 its frequency decreases several times and a periodic low frequency signal is generated at the output. If the prohibitory - control element input

S

22 a cope impulse is applied, then a single impulse input signal divider

21 will be disabled, the phase of the output signal of the divider will change towards the lag.

If on control input

0

If OR is given a command pulse, then an additional pulse is inserted at the input of the divider 21 between the two pulses of the input signal, the divider 21 counts

5 eix, and as a result, the phase of the output signal of the divider 21 is shifted in the direction of advance. When a series of command pulses are applied, the phase shift of the input signal increases in accordance with the number of pulses.

Thus, in the proposed device, all nodes and blocks can be implemented on standard elements, including ICs1X,

5 that improves manufacturability, simplifies the manufacture, configuration and operation of equipment. At the same time, in the proposed device, it is possible to test signals with variable parameters — with variable

0 by the working frequencies, the amplitude / d ratio of these signals is monitored regardless of the frequency ratings of them. separation, ratios, etc., which expands the possibilities of operational

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Claims (2)

--t.V, JPlT, g -. i.: -: - P.J .... HIS changes in the parameters of signals to be converted during work, training, training of operators. As a result, the efficiency of training of operators to work with equipment in difficult conditions as close as possible to real ones is increased. Claim 1. Radio signal simulator containing a master oscillator, connected chaser, parallel-connected simulated signal drivers with a signal level generator, which is connected via a serially connected matching unit and a real-process signal generator to the signal and parameter ratio meters. -. and a control unit connected to the simulator of simulated signals, characterized in that, in order to increase the accuracy of the simulation, it contains an auxiliary signal generator connected to a driving generator and a control unit and a unit for changing the phase of auxiliary signals connected to real process signal generators 12 sa and auxiliary signals and to the parameter ratio meter. 2. The imitator of claim 1, wherein the auxiliary phase changing unit of the auxiliary signals comprises a series-connected phase splitter, a phase discriminator, an integrator, and a voltage level meter. 3. The simulator according to claim 1, characterized in that the driver of the auxiliary signals contains sequentially connected discrete phase shifter and frequency divider. 4. The simulator of p. 3, which is also distinguished by the fact that the discrete phase divider contains a series of prohibition elements, an OR element and a frequency divider. 5. The simulator is popl, which is also distinguished by the fact that the parameter-ratio meter contains a series-connected phase discriminator, an integrator, and a threshold unit. Sources of information taken into account in the examination 1. USSR author's certificate number 549830, cl. G 09 B 23/18, 1977. 2.Certificate of the USSR on the application No. 254519/12 Cl. G 09 B 9/00, 1977 (prototype).