RU1820480C - Piezoelectric strip monolithic filter - Google Patents

Abstract

The invention relates to radio engineering and can be used in intermediate frequency paths of receiving devices as a highly selective device for receiving two- and single-band telephone communication signals. The purpose of the invention is to increase the number of bandwidths while matching their temperature characteristics. The device comprises two piezoelectric plates 1, 13. each of which is equipped with four pairs of electrodes forming a system of four resonators with acoustic and galvanic coupling. At the first plate 1, the electrodes of the first resonator are connected to the input terminals of the device .10, 11, the upper electrode of the second resonator is connected to the upper electrode of the third resonator, and the lower to the common bus 12, the upper electrode of the fourth resonator is connected to the upper electrode of the first resonator of the second plate, and the lower electrodes of the third and fourth resonators with the lower electrodes of the first and second resonators of the second plate. At the second plate 13, the upper electrodes of the second and third resonators are interconnected, the lower electrode of the third resonator is connected to a common bus 12, and the electrodes of the fourth resonator are connected to the output terminals of device 2. The filter includes a three-pin on-off switch 24, in which the movable contact is connected to a common bus 12, and stationary - with electrodes 5, 14 and 8, 9, 18, 19 of the fourth resonator of the first plate, respectively. 3 ill.

Description

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The invention relates to radio engineering and can be used in radio engineering devices, in particular in the intermediate frequency paths of receiving devices as a highly selective device for receiving two-way telephone communication signals.

The purpose of the invention is to increase the number of bandwidths while matching them

Peratural characteristics.

In Fig, 1 shows a structural diagram of the proposed device; Fig. 2 is an equivalent filter circuit for receiving two-way telephony signals; Fig. 3 is an equivalent filter circuit for receiving single-band telephony signals.

The filter includes a first piezoelectric plate 1, which is provided with upper 2-5 and lower 6-9 electrodes. The electrode system forms four cavities. The distance between the electrodes 2, 3, and 4, 5 is chosen so as to create conditions for acoustic coupling between the first and second resonators. The first and second resonators form the first link of the monolithic filter. Similarly formed the second link of the monolithic filter is the third and fourth resonator (electrodes 4-8 and 5-9). The distance between the electrodes 3 and 4 is selected so that there is no acoustic coupling. The electrodes 3 and 4 are interconnected. The upper electrode of the first resonator 2 is connected to the input potential terminal of the device 10. The lower electrodes of the first 6 and second 7 resonators are connected to the low-potential input terminal of the device 11 and with a common bus 12,

The filter includes a second piezoelectric plate 13, which is equipped with electrodes 14-21, forming a system of four resonators, a U-second plate (similar to the first), the first - second resonator and the third - fourth resonator form the third and fourth links of a monolithic filter with acoustic coupling between - by the interns. There is galvanic coupling between the links (no acoustic coupling).

At plate 1, electrode 5 is connected to electrode 14 of plate 13, and electrodes 8 and 9 are connected to electrodes 18 and 19. Electrodes 15 and .16. interconnected, electrode 17 is connected to the output potential terminal

22. And the electrodes 20 and 21 - with a common bus 12 and with a low-potential output terminal

23. The switching system includes a three-pin two-position switch 24, in which the movable contact is connected to a common bus 12, and fixed

5

0

5

0 5 0 5

.0 5

0

5

, - with electrodes 5. 14 and 8, 9, 18. 19, respectively.

Capacitors 25 and 26, in which the second terminal is connected to a common bus, can be connected to the fixed contacts of the switch 24.

The device operates as follows,

In the first position of the movable contact of the switch 24, the electrodes 8, 9 and 18 and 19 are connected to a common bus 12. In this case, the filter has the equivalent circuit shown in Fig. 2. The filter receives two-way telephony signals. In parallel with the output of the second link, a capacitance 25 may be included which determines the frequency of the upper cutoff of the filter passband. In the second position of the movable contact of the switch 24, electrodes 5 and 14 are connected to a common bus. An equivalent filter circuit for this case is shown in Fig. 3. The second and third filter links have a narrower passband, but the same lower cutoff frequency as the first, and at the fourth link.

The frequency of the upper cut-off of the passband at the second and third links is set using capacitor 26. The filter receives the signals of the lower side passband, whereby such a frequency response of the attenuation can be obtained at which the carrier frequency is partially suppressed or completely suppressed.

Two electronic keys can be used in the present device, which will increase the reliability of the device.

Claims (1)

The claims Piezoelectric strip monolithic filter, consisting of two piezoelectric plates, each of which is equipped with four pairs of electrodes, forming separate resonators in each plate, while the first plate has the first upper electrode connected to the input potential terminal of the filter, the first lower electrode is connected to a common bus, the upper second and third electrodes are interconnected, the fourth upper electrode is connected to the first upper electrode of the second plate, the fourth lower electrode is connected to the first an electrode of the second plate, in which the upper second and third electrodes are connected to each other, the fourth upper electrode is connected to the output potential terminal of the filter, and the fourth lower electrode is connected to the common bus, a capacitor is connected between the fourth upper electrode of the first plate and the common bus, distinguishing that, in order to increase the number of bandwidths when their temperature characteristics coincide, it is equipped with an additional three-pin a two-position switch, in which Koto-5 is connected to a common bus, and the third lower The fixed contacts are connected to the fourth lower electrode, the fourth pair of electrodes of the first plasti at the second plate, the first lower electrode respectively, and the movable contact is connected to the second lower electrode, and connected to a common bus, equipped with an additional third lower electrode - with a common bus. a capacitor connected .- between the fourth lower electrode of the first plate and the common bus, while the first plate has a second lower electrode  R - C 15Я i -Ј ----- J-- --hrЈ-- 23 No. Ц & МЈЬ & - p№ I that / g, 3