SU578624A1 - Arrangement for tuning the resonators of electromechanical filters - Google Patents

Description

one

The invention relates to radio engineering and can be used in the manufacture and configuration of electromechanical filters, which are widely used in various radio engineering equipment.

Devices are known that can be used to tune electromechanical filters to a given frequency, containing a sinusoidal voltage generator, amplitude manipulators that work in antiphase, an amplifier, a detector, and an indicator 1.

However, such devices have considerable time in the process of tuning the resonators of electromechanical filters and low tuning accuracy.

It is also known a device for tuning resonators of electromechanical filters, comprising a generator of continuous oscillations, connected via a first amplitude manipulator and a resonant amplifier with an electromechanical resonator sensor, a switching impulse generator controlling the operation of the first and second amplitude manipulators, a limiting amplifier, a signal frequency amplifier, connected to the indicator via a minimum limiter connected in series, the first nonlinear detector, a switching frequency amplifier the second nonlinear detector 2.

In this device, radio pulses are supplied to the electromechanical resonator sensor, the filling frequency of which is close to the resonant frequency of the tunable resonator. The oscillations excited in the resonator are amplified, rectified and fed to the indicator.

The resonant frequency search process takes a significant part of the resonator electromechanical filter tuning process, since the resonant frequency search is performed by smoothly varying the oscillation frequency of an external continuous oscillator, and a generator with a very smooth vernier device is required to obtain the required accuracy (usually a unit hertz). The timing and accuracy of tuning largely depends on the experience of the tuner.

The purpose of the invention is to improve the accuracy and reduce the tuning time of the resonators of electromechanical filters.

This is achieved in that a device for tuning resonators of electromechanical filters, containing a pulse generator, connected through an amplifier to an sensor of an electromechanical resonator and to the input of an amplifier-limiter, and a display device, has two triggers, two keys, a pulse number divider, a crystal oscillator, a counter , a register and a delay device, the output of the crystal oscillator connected to one of the inputs of the first trigger and through the first key with the input of the pulse number divider, the output of the first trigger It is connected to the first input of the second trigger, the second input of which is connected to the output of the pulse number divider, and the output is connected to the control inputs of the first and second keys, the input of the second key is connected to the output of the limiting amplifier, and the output is connected to the counter input, the outputs of which are connected to the inputs of the register, the outputs of which are connected to the display device, while the control inputs of the counter and register are connected to the output of the divider number of impulses, and the second input of the first trigger through the delay device is connected to the output of g generator of pulses.

The drawing shows a block diagram of the proposed device.

The device contains a pulse generator 1, an amplifier 2, a sensor with an electromechanical resonator 3, a limiting amplifier 4, a crystal oscillator 5, keys 6 and 7, delay element 8, triggers 9 and 10, pulse number divider II, counter 12, register 13 and a block 14 digital display frequency.

The device works as follows.

The impulse from the generator 1 through the amplifier 2 is fed to a sensor with an electromechanical resonator 3 and in the latter generates synzsoidal damped oscillations. In parallel, this pulse through the delay element 8 is fed to the 5-input of the trigger 9, and the / -input of this trigger receives pulses from the crystal oscillator 5.

The impulse coming from oscillator 1 sets the TRIGGER 9 to the state "1", and the first impulse, coming from the crystal oscillator 5, returns the trigger 9 to the state "O."

The impulse 9 generated in such a way enters the 5-input of the trigger 10 and stops the latter in the back state to the “1” state, which, in turn, causes the opening of keys 6 and 7.

The damped oscillations of the sensor with an electromechanical resonator 3 are amplified by the amplifier-limiter 4 and through the open key 7 enter the counter 12. At one time, the pulses from the crystal oscillator 5 through the key 6 enter the divider 11. Filling the divider 11 takes place until a certain number n, when reached at / the trigger input from divider 11 is given a signal that sets trigger 10 to the state "O." In this case, the keys 6 and 7 are closed.

During the time during which the key 7 was opened, one bundle of resonance frequency pulses of the electromechanical resonator would arrive at the counter 12.

Due to the relatively fast decay of oscillations in an electromechanical resonator, it is not possible to measure the resonant frequency of an electromechanical resonator with a sufficient degree of accuracy in one cycle. Therefore, with the arrival of the next pulse from the pulse generator 1 to the sensor with the electromechanical resonator 3, the onboard step is repeated.

After the number of cycles L - (L is the division factor of divider 11), counter 12 records the statistically averaged value of the resonant frequency of the electromechanical resonator, since the opening time of the key 7 (i.e., the start time of filling the counter 12) is random in relation to the phase of oscillations resonant frequency of the electromechanical resonator.

Upon reaching the number of cycles A from the output of the divider 11, the control inputs of the register 13 are given a signal to transfer the resonant frequency of the electromechanical resonator recorded in the counter 12 to the outputs of the register 13 to which the inputs of the digital frequency display unit 14 are connected. Block 14 digital frequency display indicates the measured resonant frequency

of the electromechanical resonator, and the counter 12 is reset by the signal received from the divider I. At this, the measurement ends.

The delay element 8 creates a delay signal for opening keys 6 and 7, which is necessary for damping transients in the sensor itself, thereby enhancing the measurement accuracy.

Claims (2)

1. Petrov A.N., Shmatchenko V.F. Bandpass Electromechanical Radio Frequency Filters, M, Gosenergoizdat, 1961, p. 255-258. 2. USSR author's certificate number 24306 cells. G O Sh 23/00, 1962.