RU2014727C1 - Device for automatic tuning of selective amplifier - Google Patents

Abstract

FIELD: electronics. SUBSTANCE: device for automatic tuning of selective amplifier includes controlled step attenuator, retunable selective amplifier, amplitude detector and threshold element connected in series. Output of first digital actuating element is connected to control input of controlled step attenuator which input is input of device. Pulse counter, code comparator, flip-flop and first coincidence element are connected in series and are placed between output of amplitude detector and first input of second digital actuating element. Unit of registration of extremum is connected between output of threshold element and second input of flip-flop. Output of clock pulse generator is coupled to second inputs of first and second coincidence elements. Second input of flip-flop is linked to third input of second coincidence element, output of second digital actuating element is connected to controlling input of selective amplifier. Output of storage register is coupled to second input of code comparator. Inputs of first and second digital actuating elements of first coincidence element, second input of storage register and second input of pulse counter are input for signal START. Input of storage register is input for code signal on number of harmonic of input signal. Tuning of device to frequency of input signal is accomplished continuously beginning from start of frequency range and is stopped when number of responses from output of amplitude detector equates number corresponding to number of harmonic entered into storage register. EFFECT: improved accuracy and efficiency of tuning. 2 dwg

Description

 The invention relates to radio engineering and can be used to automatically tune selective systems to a given harmonic number of the input signal.

 A device for automatically measuring the frequency of continuous oscillations of the microwave range, containing a tunable ferrite filter, a sawtooth current control frequency of the filter settings, an amplitude detector, a differential cascade, a zero-organ, a start-up circuit and a shaper of the time interval. In this device, the ferrite filter is automatically tuned to the signal of the measured frequency to the maximum transmission coefficient of the filter. The value of the measured frequency is proportional to the duration of the time interval formed from the moment the linear tuning of the filter begins until the filter is adjusted to the maximum output signal.

 If there are spurious components in the spectrum of the input signal, errors in determining the frequency value are possible, which corresponds to tuning the filter to the frequency of the minor signal. Another important disadvantage of the device is that it is impossible to program the filter to the required harmonic number in the case of the presence of an input signal in the form of components of a regular frequency spectrum.

 A device for discrete automatic tuning of a selective amplifier is also known, comprising a controlled step attenuator, a tunable selective amplifier, an amplitude detector, a threshold element, a clock signal switch, a clock generator, first and second digital actuators, a memory register, a switching unit, and a reset circuit.

 In terms of composition and principle of operation, this device is closer to the claimed technical solution and is therefore selected as a prototype.

 In this device, the tuning of the selective amplifier to the maximum transmission coefficient is carried out automatically in cycles, starting from the beginning of the frequency range with the attenuator fully open. In each cycle, the frequency amplifier is first tuned in frequency until the threshold element is triggered, then digital information about the level of the control voltage of the selective amplifier is recorded in the memory register and memory is adjusted and the attenuation (attenuation) of the step attenuator is adjusted until the threshold circuit is released.

 After that, a new cycle of tuning the selective amplifier is repeated. So, the amplifier is tuned in cycles until the maximum transmission coefficient is reached, then the tuning of the amplifier continues continuously until the second digital actuator overflows. The overflow signal disconnects the actuator from the control input of the amplifier and connects the output of the memory register with information corresponding to the maximum gain of the amplifier to the control input of the amplifier.

 The device works efficiently with a clean input signal spectrum. If there is noise in the spectrum of the input signal, regular components and harmonics, tuning to the working signal is impossible. The device also does not allow tuning of the amplifier (selective system) to a given (programmable) harmonic sequence number even with a stable and regular input signal spectrum.

 The purpose of the invention is to increase the speed and reliability of the automatic tuning of the selective amplifier to any given harmonic of the frequency spectrum of the input signal.

 This is achieved by the fact that in a device containing a series-connected input, a controlled step attenuator, a tunable selective amplifier, the output of which is the device output, an amplitude detector and a threshold element, as well as a first digital actuator whose output is connected to the control input of the controlled step attenuator, a second digital actuator, a memory register and a clock generator, wherein the inputs of the first and second digital actuators are is the inputs for the Start signal, and between the output of the amplitude detector and the first input of the second digital actuator are connected in series a pulse counter, a code comparison unit, a trigger and a first coincidence element, a second element is introduced between the output of the threshold element and the first input of the first digital actuator coincidence, between the input of the threshold element and the second input of the trigger, an extremum fixing block is introduced, while the output of the clock generator is connected to the second inputs the first and second coincidence elements, the second trigger output is connected to the third input of the second coincidence element, the output of the second digital actuator is connected to the control input of the selective amplifier, the second input of the memory register and the second input of the pulse counter is an input for the Start signal, the output of the memory register is connected with the second input of the code comparison unit, and the input of the memory register is the input for the code signal about the harmonic number of the input signal.

 The essence of the invention lies in the fact that due to the introduction of new nodes and connections into the known device, the selective amplifier is tuned to the input signal frequency not in cycles as in the prototype (first, the amplifier is discretely frequency-tuned before the threshold circuit operates, the information about the amplifier control signal level is stored and discretely reduce the input signal level with the help of an attenuator until the threshold circuit is released, thus approximating the maximum amplitude-frequency characteristic every time amplifier characteristics to the frequency of the input signal), but continuously, starting from the beginning of the frequency range.

 In the prototype, the stepped attenuator is tuned in each tuning cycle of the selective amplifier. In the proposed device, the attenuator works after tuning the amplifier, bringing the output level of the device to the desired value, determined by the specified level of the reference voltage of the threshold element. During the tuning of the selective amplifier, the controlled step attenuator is open and pulse signals (responses) appear each time the amplitude detector exits when the amplitude-frequency characteristics of the amplifier pass through each harmonic of the input signal. The tuning process is terminated only when the number of responses from the output of the amplitude detector is compared with the number corresponding to the tuning harmonic number entered in the memory register, and the tuning tuning is stopped when the programmed response passes through a maximum, which corresponds to the maximum transmission coefficient of the frequency-selective amplifier system.

 At the moment of termination of the tuning of the amplifier, a permit for discrete tuning of the attenuator is issued, which leads to a weakening of the input signal and, accordingly, a decrease in the level of the output signal and the signal at the output of the amplitude detector. At the moment of equality of the detector output voltage and the specified voltage of the support (the threshold element is triggered), the tuning process is terminated.

 The proposed set of features of this device exhibits a new property based on various approaches to finding the maximum transmission coefficient of the frequency-selective amplifier system (compared to the prototype): optimizing the tuning of the selective amplifier to a given frequency component of the regular harmonic signal when searching for the maximum transmission coefficient of the amplifier by finding the extremum response of the amplitude-frequency characteristics of the amplifier at the output of the amplitude detector.

 In FIG. 1 is a structural electrical diagram of a device for automatically tuning a selective amplifier to a given harmonic number of an input signal; in FIG. 2 is a timing diagram explaining the operation of the device.

 A device for automatically tuning a selective amplifier to a given harmonic number of the input signal contains a tunable selective amplifier 1, a second coincidence element 2, a second digital actuator 3, a memory register 4, a stepped attenuator 5, a first digital actuator 6, an amplitude detector 7, a threshold element 8, the first coincidence element 9, a clock pulse generator 10, input 11 for the Start signal, trigger 12, code comparison unit 13, extremum fixing unit 14, pulse counter 15, input 16 input code signal about the number of harmonics.

 The input of the device is connected to the input of a controlled step attenuator, the output of which is connected to the input of a tunable selective amplifier, the output of which is the output of the device, and also connected to the input of an amplitude detector, the output of which is connected to the input of a threshold element, the output of which is connected to the first input of the first digital actuator the output of which is connected to the control input of the controlled step attenuator, the output of the amplitude detector is connected to the first input of the pulse counter s and with the input of the extremum fixation unit, the output of which is connected to the second input of the trigger, the first input of the trigger is connected to the output of the code comparison unit, the first input of which is connected to the output of the pulse counter, the second input of the pulse counter is connected to the second input of the memory register, with the signal input " Start ", with the second inputs of the first and second digital actuators and with the third input of the first coincidence element, the second input of which is connected to the output of the clock and with the second input of the second element adenia, the first input of the first coincidence element is connected to the first output of the trigger, the second output of which is connected to the third input of the second coincidence element, the output of the first coincidence element is connected to the first input of the second digital actuator whose output is connected to the control input, the first input of the memory register is connected to input for entering information about the harmonic number.

 The device operates as follows.

 Prior to the start of the process of automatic tuning of the selective amplifier 1, a working signal containing a regular frequency spectrum is received at the input of the device (Fig. 2 a). Digital actuators 3, 6, counter 15 pulses and register 4 are in the initial state. The frequency-selective system of the amplifier 1 is located at the beginning of the working frequency range (Fig. 2b), the attenuation of the step attenuator 5 is minimal, the counter 15 is reset. In register 4 through the input 16 of the input of digital information is entered a number equal to the number of harmonics of the input signal, which you want to configure tunable amplifier 1, for example, the number n-1 (Fig. 2B).

 To carry out the tuning of the amplifier at time t 1, the “Start” signal is sent to input 11 in the form of a potential level (Fig. 2e). This command gives permission to operate the digital actuators 3, 6 and the pulse counter 15. Moreover, through the first element 9 matches the clock pulses (Fig. 2e) of the generator 10 are fed to the control input of the second digital actuator 3 (Fig. 2g). The arrival of clock pulses in the actuator 3 changes the control voltage at the input of amplifier 1 (Fig. 2d) and, accordingly, the tuning frequency (Fig. 2b).

 The frequency tuning of the selective system of amplifier 1 leads to the appearance of pulses (responses) at the output of the amplitude detector 7 (Fig. 2h) at each harmonic of the input signal (Fig. 2a), as well as pulses (Fig. 2i) at the output of the fixation block of the extremum 14 the moments of reaching the maximum voltage value at the output of the amplitude detector 7. In this case, the number will increase in the pulse counter 15 and when the value (n-1) is reached, the code comparison unit 13 outputs a signal in the form of a potential level (Fig. 2k), and the block level fixation - and pulse (Fig. 2i) - time t 2. The presence of these signals at the first and second inputs of trigger 12 triggers a trigger 12, which by a signal from the first output (Fig. 2n) closes the first element 9 and a signal from the second output (Fig. 2m ) opens the second element 2. The pulses of the clock 10 are no longer fed to the first input of the second digital actuator (Fig. 2g), but are fed to the second input of the second element of coincidence 2 and, accordingly, to the first input of the first digital actuator 6 (Fig. 2o).

 Under the action of clock pulses, the voltage at the control input of the step attenuator increases, which leads to an increase in attenuation and, accordingly, to a decrease in the voltage at the output of the amplitude detector (Fig. 2h). Adjustment (reduction) of the voltage level at the output of the amplitude detector 7 continues until the moment 3 of the threshold element 8 is triggered. The second voltage coincidence element 2 is closed by the output voltage (Fig. 2l) of the threshold element 8, clock pulses do not pass to the input of the first digital actuator 6 and attenuation adjustment attenuator 5 is terminated. As a result, the device is tuned to the specified harmonic number of the input signal and outputs a constant level of this harmonic, determined by the level of the reference voltage of the threshold element.

 Thus, the proposed device has wider functionality in comparison with the prototype, since depending on the number entered in the memory register it allows tuning both to a single frequency component of the spectrum of the input signal and to any desired harmonic component of the complex spectrum of the input signal, starting from the 1st (lower in frequency) and ending (upper).

 In addition, in the presence of undesirable components of the spectrum (for example, regular interference) of the input signal, the device avoids tuning to those, which increases the reliability of the system in the presence of interference. Compared with the prototype, the device has a higher speed, since here the adjustment to the maximum transmission coefficient is not carried out cyclically, but continuously until the extremum of the programmed response number of the frequency response is reached.

 The proposed device is performed on a modern elemental base. The extremum fixation circuit is made on a differential amplifier with nonlinear feedback and storage capacity. At the output of the extremum fixation circuit there is a comparator. In the device for automatic tuning of the electoral system, a FFLK2-19B type ferrite tunable filter, a microwave amplifier type M421131, a controlled attenuator made on pin diodes, a microwave-varactor type harmonic generator, a matching circuit, a trigger, a code comparison circuit, a memory register, a counter are used in the device pulses on microcircuits of series 133, 533, digital actuators on microcircuits of series 533, 572, 140, threshold element on microcircuit of series 521, scheme for fixing the extremum on microcircuits of series 140, 521.

Claims (1)

 DEVICE FOR AUTOMATIC TUNING OF THE SELECTOR AMPLIFIER, containing a serially connected controlled step attenuator, the input of which is the input of the device, a tunable selective amplifier, the output of which is the output of the device, an amplitude detector and a threshold element, as well as a first digital actuator whose output is connected to the control input of the controlled step attenuator, second digital actuator, memory register and clock generator, at the inputs of the first and second digital actuators are inputs for the Start signal, characterized in that, in order to increase the speed and reliability of tuning to any given harmonic of the frequency spectrum of the input signal, between the output of the amplitude detector and the first input of the second digital actuator are included serially connected pulse counter, code comparison unit, trigger and the first coincidence element, between the output of the threshold element and the first input of the first digital and an additional element, a second coincidence element is introduced, and an extremum block is introduced between the output of the threshold element and the second trigger input, while the output of the clock generator is connected to the second inputs of the first and second coincidence elements, the second output of the trigger is connected to the third input of the second coincidence element, the output of the second digital actuator connected to the control input of the selective amplifier, the second input of the memory register and the second input of the pulse counter are the input for the signal "P accele ", the output of the memory register is connected to the second input of the code comparison unit, and the input of the memory register is the input for the code signal about the harmonic number of the input signal.

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