SU886217A1 - Device for automatic tuning of selective amplifier - Google Patents

Description

one

The invention relates to radio engineering and can be used in tuning amplifiers of radio transmitting and receiving devices.

Known devices for automatic tuning of the selective amplifier.

One of the known devices for automatically adjusting a selective amplifier to the middle of a passband comprises a tunable amplifier to the output of which. connected in series detector, trigger 1 imidta, differential-. a fencing circuit and a control trigger; a clock generator is connected to the control input through a serially connected actuator in the form of a binary reversible counter and a key; and a frequency divider is connected to the switch output via a serially connected frequency divider. two and the switch is connected to an additional binary reversible counter.

A reset pulse source 1 is connected to the control input of which and to the control inputs of the actuating element and the control trigger.

The disadvantages of this device are the complexity of its design and low speed due to the fact that in a wide frequency range the tuning step remains constant at 1 m.

The closest in technical essence of the present invention is an automatic tuning device for a selective amplifier, comprising a selective amplifier connected in series, to the control input of which a binary counter, an amplitude detector, a Schmidt trigger, a differentiating circuit and a control trigger, a control trigger and a binary counter are connected connected to the output of the source of the pulses of the reset, to the signal input of the binary counter 3 connected in series generator In the known device, the increase in speed is achieved only in the passband of the selective amplifier, which is only a small segment spent on setting the time, since almost always the tunable frequency range far exceeds the limits of the passband of the selective amplifier. The purpose of the invention is to increase speed. The goal is achieved by the fact that in the device for automatic tuning of a selective amplifier containing a series-connected selective amplifier, to the control input of which a binary counter, an amplitude detector, a PYidt trigger, a differentiating circuit and a control trigger are connected, the control trigger trigger inputs and the binary counter is connected to the output of the source of the pulse pulses to the signal input of the binary counter connected in series to the generator of the pulses and the key, to the control input of the gates A power amplifier is connected to the sawtooth generator, the control and installation inputs of which are connected to the additional output of the Schmidt trigger and the source of reset pulses from the controller, the first control inputs of the switch and the binary counter are connected to the output of the control trigger, and the second control inputs of the key and the binary counter are connected to each other by the output of the Schmidt trigger. FIG. 1 shows the device block diagram; in fig. 2 is a diagram (a, b, c, d, e) of the voltage variation at the outputs of various units of the device. The automatic tuning device of the selective amplifier contains a selective amplifier 1, a binary counter 2, an amplitude detector 3, a trigger 4, a differentiating circuit 5, a control trigger 6, a source 7 of reset pulses, a generator of 8 pulses, a switch 9 and a generator 10 of sawtooth voltage Device It works the following way. Before starting the supply of the signal from the source 7 of the reset pulses 4 to the initial (zero) position, the binary counter 2, the control trigger 6 and the sawtooth generator 10 are started, which corresponds to the time t (Fig. 2), FIG. 2a shows the voltage variation at the output of the trigger 4; in fig. 26 — voltage variation at the output of the trigger 6; in fig. 2c change in voltage and At the output of key 9; in fig. 2d is the change in voltage at the output of the generator 10; in fig. 2d - voltage variation at the output of binary counter 2. The selective amplifier 1 is controlled by the sawtooth voltage generator 10 until the signal at the output of the executive amplifier 1 reaches a certain level. Upon reaching the latter at time t, Schidt's trigger 4 (Fig. 2a) is triggered, which converts the sawtooth voltage generator 10 into a DC amplifier mode that maintains the output voltage constant (Fig. 2d). In addition, the signal from the Schmidt trigger output 4 sets the binary counter 2 to a state corresponding to some pre-selected number K, and simultaneously opens the key 9, as a result of which the counter 2 starts to receive pulses from the generator 8 (Fig. 2b). Thus, at time ti, at the output of counter 2, some initial voltage is set (Fig. 2d). As the tuning frequency of the selective amplifier 1 is further changed away from the frequency of the input signal, the output voltage of the amplitude detector 3 decreases. When this voltage reaches the threshold value of Schmidt’s trigger 4 at the time t, the latter returns to the initial state, and its output pulse, having passed through the differentiating circuit 5, overturns the control trigger 6 (Fig. 2b). The output signal of the control trigger 6 closes the key 9 and turns off the generator 8 of the pulses of binary counter 2, on whose input a control voltage D U is set at this moment in time proportional to the code in binary counter 2 corresponding to the bandwidth of the selective amplifier 1 (Fig. 2d ). At the same time, the signal from the output of control trigger 6, arriving at the rewriting input of binary counter 2, shifts the code recorded in it. Since in the binary code the shift operation is equivalent to dividing by two, at the output of the binary counter 3 a control voltage di / 2 is set, corresponding to the middle of the passband.

Claims (2)

1. USSR Author's Certificate No. 590848, cl. H 03 J 5/00, 1978. 2. USSR author's certificate No. 362461, cl. H 03 J 5/00, 1970 (prototype /. It, IT t (ffuf.l