RU2454676C2 - Apparatus for simulating electric signal nonlinear distortions - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: two automatic attenuators are further placed at the input and output of the apparatus, said attenuators being simultaneously controlled by an output signal from a comparator unit, which is generated as a result of comparing the signal from the output of the input attenuator and the signal from a reference voltage unit. There are also two display units indicating correct tuning of the attenuators, which enables to improve functionality of the apparatus by using automatic tuning with indication of its operation, and increase its universality with respect to external devices by enabling operation of the apparatus in a wide range of input signal. Equality of the values of the input and output signals is ensured and the possibility of using manual control of tuning the apparatus is also maintained by using an additional two-way switch.

EFFECT: improved functionality of the apparatus and high universality thereof with respect to external devices.

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Description

Technical field

The invention relates to the field of measurement technology and is intended to simulate various types of nonlinear distortions of an electrical signal and can be used to conduct a comparative assessment of the sensitivity of standardized and newly proposed methods for measuring the amplitude nonlinearity of sound amplification equipment, to conduct subjective examinations of the noticeability of distortions on signals of various shapes, including signals of audio programs, for other scientific purposes, as well as for educational purposes process.

The purpose of the invention is to improve the functionality of the device and increase its versatility with respect to external devices.

This is achieved by using the automatic adjustment of signal levels at various points of the device circuit with an indication of the correctness of this setting, as well as by expanding the range of possible values of the input signal and ensuring the equality of the values of the input and output signals of the device, for which input and output automatic attenuators, a comparison unit, controlling their operation, two blocks for indicating their settings and a reference voltage block, and to preserve the possibility of manual control of device settings and introduced an additional on-off switch.

Description of analogues

A device is known, which is the simplest model of an amplifier and contains three groups of cascades covered by a common negative feedback circuit. The structure of the model reflects the most common principle for constructing circuits of semiconductor amplifiers of audio signals in discrete and integral versions [1]. The model reflects the presence of linear and nonlinear distortions in individual groups of cascades and in the amplifier as a whole.

The reasons that impede the achievement of the required technical result include the inability to use the device as a simulator of various types of distortion, because There is no way to change the appearance and adjust the degree of introduced distortion.

Prototype description

The closest solution to the same purpose for the totality of features is a device that is a simulator of dynamic distortion [2].

The device contains input and output terminals for connecting external devices, between which are located the series-connected first amplifier stage, connected to the input terminal by its non-inverting input, a correction stage and the second amplifier stage, and also includes a common negative feedback circuit connected by its input to the output of the second amplifier stage, and with its output - with the inverting input of the first amplifier stage, the level indicator connected to the output terminal, the first nonlinear the second circuit connected either to the output of the first amplification stage or to the output of the second amplification stage using a two-position switch, the second nonlinear circuit connected to the output of the second amplification stage using a switch, a manual control unit connected to the non-inverting input of the first amplification stage, while the correcting step, the manual control unit and both non-linear circuits are tunable.

The construction of the known device meets current trends in the design of amplification equipment: essentially non-linear and inertial input, intermediate and output stages are covered by a common negative feedback circuit. At the same time, the device includes blocks that allow it to be configured.

Prototype criticism

The reasons that impede the achievement of the required technical result when using the known device adopted as a prototype include the fact that the device is configured only manually using the manual control unit, by changing the signal at the input of the first amplification stage, with simultaneous manual control of the settings of nonlinear circuits that control the degree of introduced distortion. At the same time, the results of the settings can be judged only by the readings of the level indicator. With a wide range of possible values of the input signal, and even more so when working with signals of audio programs of various genres, it is functionally difficult to configure a prototype device that is adequate to the desired degree of distortion. In addition, the use of a prototype device as part of a measurement setup or in a sound reproduction path introduces unpredictable changes to the level of the end-to-end signal.

SUMMARY OF THE INVENTION

The problem to which the invention is directed, is to improve the functionality of the device and increase its versatility with respect to external devices.

This problem is solved by achieving a technical result in the implementation of the invention, which consists in applying automatic adjustment of signal levels at various points of the device circuit with an indication of the correctness of this setting, as well as in expanding the range of possible values of the input signal and ensuring the equality of the values of the input and output signals of the device.

The specified technical result in the implementation of the invention is achieved by the fact that the input and output automatic attenuators, a comparison unit that controls their operation, two display units for the correctness of their settings and a reference voltage unit are introduced into the device, and an additional two-position switch is introduced to maintain the possibility of manual control of the device settings.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, made it possible to establish that the applicant did not find analogues that are characterized by features identical to all the essential features of the claimed invention, and the definition of the prototype identified among the identified analogues as the closest in the totality of features , allowed to determine the set of essential in relation to the technical result of the features in the claimed device set forth in the claims.

Therefore, the claimed invention meets the requirement of "novelty" of the current legislation.

To verify the conformity of the claimed invention to the requirements of the inventive step, the applicant conducted an additional search for known solutions in order to identify features that match the features distinctive from the prototype, the results of which showed that the claimed invention does not follow explicitly from the prior art, as the prior art determined by the applicant, the effect of the transformations provided for by the essential features of the claimed invention on the achievement of those nical result.

Therefore, the claimed invention meets the requirement of "inventive step" of the current legislation.

List of drawings

The figure shows a structural diagram of a device that implements the invention, where 1 is the input terminal; 2 - the first amplification stage; 3 - corrective step; 4 - second amplification stage; 5 - a chain of general negative feedback; 6 - level indicator; 7 - the first nonlinear circuit; 8 - the first on-off switch; 9 - the second nonlinear circuit; 10 - switch; 11 - manual control unit; 12 - output terminal; 13 - the first automatic attenuator; 14 - second automatic attenuator; 15 is a block comparison; 16 - second on-off switch; 17 - block reference voltage; 18 - the first setting indicator; 19 is the second setting indicator. Blocks 3, 7, 9, and 11 are tunable, and blocks 13 and 14 are tunable at the same time.

Information confirming the possibility of carrying out the invention

Information confirming the possibility of carrying out the invention with the receipt of the specified technical result are as follows.

The device contains input 1 and output 12 terminals for connecting external devices, between which are connected the first automatic attenuator 13, the first amplifier stage 2, connected to the output of the first automatic attenuator with its non-inverting input, the correcting stage 3, the second amplifier stage 4, and the second automatic attenuator 14, the device also contains a circuit 5 of general negative feedback, the input of which is connected to the output of the second amplification stage 4, and the output to the inverter to the input of the first amplifier stage 2, the level indicator 6 connected to the output terminal 12, the first non-linear circuit 7, connected either to the output of the first amplifier stage 2 or to the output of the second amplifier stage 4 using the first on / off switch 8, the second non-linear circuit 9, having the ability to be connected to the output of the second amplification stage 4 using the switch 10, the comparison unit 15, which performs coordinated control of the automatic attenuators 13 and 14 with its output signal supplied simultaneously o to the control inputs of the attenuators, the reference voltage unit 17 is connected to the first input of the comparison unit, and the second input of the comparison unit using the second on-off switch 16 can be connected either to the output of the first automatic attenuator 13 or to the manual control unit 11, the first display unit 18 settings connected to the output of the first automatic attenuator 13, the second settings display unit 19 having two inputs, the first of which is connected to input terminal 1, the second to output terminal 12. Single stage 3, manual control unit 11, nonlinear circuit 7, non-linear circuit 9 are made tunable and both automatic attenuator rebuilt simultaneously.

Amplification stages 2 and 4 of the device are quasilinear. The nonlinearity of these stages is formed by connecting tunable non-linear circuits 7 and 9 to their outputs. Connecting the first circuit 7 to the output of the first amplification stage 2 or the output of the second amplification stage 4 allows you to simulate distortion type distortion: symmetrical "soft", symmetrical "hard", asymmetric "soft", asymmetric "hard".

In combination with the adjustable linear distortions introduced by the correcting stage 3, connecting the first circuit 7 to the output of the first amplifying stage 2 allows you to simulate the so-called dynamic intermodulation distortion, which degrade the sound of loud, rapidly changing audio signals.

Connecting the second nonlinear circuit 9 to the output of the second amplification stage 4 allows you to enter distortions of the type of "Central cut-off", characteristic of the operation modes of class B of the end stages of the power amplifiers of the audio signal. To them can be added distortion type "restriction" by connecting the first nonlinear circuit 7 to the output of the second amplification stage 4.

It is also possible to combine non-linear distortions of the “restriction” type in the first amplification stage 2 and distortions of the “central cut-off” type in the second amplification stage 4 and a combination of dynamic intermodulation distortions and distortions of the “central cut-off” type in the second amplification stage 4.

In the process of operation of the inventive device, there may be cases of its incorporation into points of a measuring installation or a sound reproduction path different in signal level. In this regard, the device must have a wide range of input voltages with a guaranteed hit in the nonlinearity zone, introduced using a nonlinear circuit 7 when it is connected both to the output of the first amplification stage 2 and to the output of the second amplification stage 4. In addition, to the input terminal 1, the sources of the test signal and the signal of audio programs can be connected, the output signal level of which can be of any value in a wide range of values. The first automatic attenuator 13 allows you to bring the possible signal levels of the sources to a given value of the input signal level of the first amplification stage 2. The attenuator 13 is configured automatically using the signal supplied to the control input generated by the comparison unit 15, as a result of the effect of the signal output from its first input the first attenuator 13, and to its second signal input from the output of the reference voltage block 17. The comparison unit 15 generates an error signal that controls the degree of attenuation introduced by the attenuator 13, which occurs until the signal level set by the reference voltage unit 17 is reached at the non-inverting input of the first amplification stage 2, corresponding to the maximum output signal of the stage 2 or stage 4 into the nonlinearity region, which is introduced into these steps by alternative connection with the on-off switch 8 of the first nonlinear circuit 7, which is guaranteed by the distribution leniem signal levels between the device stages. Non-linear circuit 7 has several tunable elements smoothly and (or) discretely, access to which is ensured by the design of the front panel of the device.

The first tuning indication block 18 provides visual control of reaching a predetermined signal level at the output of the attenuator 13, and therefore at the input of the first amplification stage 2. Next, the signal enters the correction stage 3, the degree of inertia of which can be adjusted smoothly and (or) discretely using the adjustment bodies, made on the front panel of the device.

From the output of the correcting stage 3, the signal enters the second amplification stage 4, to the output of which, to simulate distortions, the first nonlinear circuit 7 and / or the second nonlinear circuit 9 can be connected using switch 8, connected using switch 10 and introducing adjustable ones using tunable distortion elements of the "central cut-off" type.

On the circuit 5 of the general negative feedback, the signal from the output of the second amplification stage 4 is fed to the inverting input of the first amplification stage 2. This imitates the operating principle widely used in the construction of transistor amplifiers in integral and discrete versions.

The inventive device imitates an amplifier having a certain gain, therefore, for the convenience of operation of the device as part of a measuring installation or in the sound reproduction path, it is necessary to introduce attenuation into its output signal to such an extent that the signal values at the input and output of the device are equal. It is the second automatic attenuator 14 that provides equalization of signal levels at the input and output of the device, which will allow you to not make changes to the signal level at the connection point of the device when working with the inventive device. The second attenuator 14 changes the degree of attenuation introduced into the output signal of the device under the influence of the signal supplied to its input by the comparator 15, which also controls the first attenuator 13. The second tuning indication unit 19 provides visual control of the achievement of the equality of signals at the input and output of the device. One of its inputs is connected to input terminal 1, the other to output terminal 12.

Manual tuning with the help of tunable elements of the manual control unit 11 can be used when working with audio signals or in other cases if any circumstances or considerations require it. The transition to manual control is carried out by moving the switch 16 to an alternative position. In this case, the correctness of the device settings can be judged by the readings of the level 6 indicator, the pointer of which should be in the working sector of the indicator scale, which is achieved by manual adjustment of block 11.

The above indicates that the introduction of automatic attenuators at the input and output of the device, simultaneously controlled by the output signal of the comparison unit, generated by it as a result of comparing the signal from the output of the input attenuator and the signal of the input reference voltage unit, as well as the introduction of two display units, indicating the correct settings attenuators while maintaining the ability to use manual control of device settings using an optional on-off switch, allows you to improve the functionality of the device and increase its versatility with respect to external devices by providing the ability to operate the device in a wide range of input signal values and maintaining the equality of the values of the input and output signals of the device.

Thus, the above information indicates the fulfillment of the following conditions when using the claimed invention:

- a device embodying the claimed invention in its implementation, is intended for use in the field of instrumentation and is intended to simulate various types of nonlinear distortions of an electrical signal for scientific and educational purposes;

- for the claimed invention in the form described in the claims, the possibility of its implementation using the methods described above or known before the priority date of the funds is confirmed;

- a device embodying the claimed invention in its implementation, is capable of achieving the specified technical result.

Therefore, the claimed invention meets the requirement of "industrial applicability" under applicable law.

Literature

1. Tikhonova L.S. Sensitivity analysis of standard methods for measuring nonlinearity to dynamic distortions. - Technique of film and television, 1985, No. 7, p.15-19.

2. Zhuravlev V.M., Galushkin A.E., Tikhonova L.S. Dynamic distortion simulator. - L .: Ed. FACES. Sat scientific Proceedings: Trends and prospects for the development of domestic film technology, 1985, p.66-71 - prototype.

Claims (1)

A device for simulating nonlinear distortion of an electrical signal, containing input and output terminals for connecting external devices, between which are located the series-connected first amplification stage, connected to the input terminal by its non-inverting input, a correction stage and a second amplification stage, and also including a common negative feedback circuit connected by its input to the output of the second amplification stage, and by its output - with the inverting input of the first amplification stage, ind a level indicator connected to the output terminal, a first non-linear circuit connected either to the output of the first amplification stage or to the output of the second amplification stage using a two-position switch, a second non-linear circuit connected to the output of the second amplification stage using a switch, a manual control unit connected with a non-inverting input of the first amplification stage, while the correction stage, the manual control unit and both non-linear circuits are tunable, characterized in that The first automatic attenuator connected between the input terminal and the non-inverting input of the first amplifying stage, the second automatic attenuator connected between the output of the second amplifying stage and the output terminal, the comparison unit and the reference voltage unit connected to the first input of the comparison unit, an additional two-position switch disconnecting the connection between the non-inverting input of the first amplifying stage and the manual tuning unit and connecting the second input of the comparison unit or with non-inverting the input of the first amplification stage, or with the manual control unit, the output of the comparison unit is simultaneously connected to the control inputs of the first and second automatic attenuators, in addition, two tuning indication blocks are introduced, the first tuning indication block is connected to the output of the first automatic attenuator, the first input of the second indication block settings is connected to the input terminal, and the second input of the second display unit is connected to the output terminal.