SU683565A1 - Device for tuning electromechanical filters - Google Patents

Description

The invention relates to radio electronics and can be used for adjusting a single "p01B atom of electromechanical filters (EMF).

There are known devices for tuning the EMF based on the change in the resistance of the sensor coil in which the resonator is placed, ir: And the combination of the generator frequency with its own frequency of the resonator 1.

The closest IK of the invention is a device that sequentially connects an external generator, a first key, a sensor, a driver, and a VTO / swarm key, a pulse generator. Comm. Switch, the outputs of which are connected to the second inputs of the keys, and a series-connected high amplifier frequencies, first amloud detector, amplifier LIZKO frequencies, second amplitude detector and indicator 2.

However, these devices have a sufficiently high sensitivity.

The purpose of the invention is to increase the sensitivity of the device.

For this, a device containing a series-connected external generator, a KEY, a sensor, a guard and a second key, a generator, switching pulses, the outputs of which are connected to the second inputs of the switches, and a series-connected high-frequency amplifier, the first amlitzdny detector, 1 LOW amplifier frequencies, the second amplitude detector and the indicator, additionally included between the output of the second key and the input of the high frequency amplifier and connected in series the main balanced mixer, knots kopolosny filter and friction key, as well as sequentially connected heterodyne, fourth key, additional balanced mixer and notch filter, the output of which is connected to the second input of the main balanced mixer, the second input of the additional balanced mixer is connected to the output of the external generator, and the second inputs of the third And -four keys are connected to the outputs of the generator of switching pulses.

The schematic diagram shows a block diagram of a device for tuning an EMF containing an external generator / connected via KEY 2 to sensor 3, a remote device 4, whose input is connected to 3, and the output to key 5; the main mixer 6, one of the inputs of which is connected to the key 5, and the other through a notch filter 7 connected to the output of the additional balanced mixer 8; one of the inputs of the mixer 8 is connected with the help of the key 9 with the output of the local oscillator 10, and the other input of the mixer 8 coeers; .rnen with the output of the generator /, the output of the mixer 6 includes the narrow-band filter //, the output connected to the key 12; the high-frequency input / silicon 13 is connected to the i2 key, and the output to the amplitude detector 14; the input of the low-frequency amplifier 15 is connected to the detector 14, and the output through the amplitude detector 16 with a switch end 17; the output 18 of the switching pulse generator is connected to the control inputs of switch 2, output 19, respectively, to the control input of switch 9 and switch 5, and output 20 to control switch of switch 12.

The device works as follows.

The signal from the external generator 1 is applied to the key 2. At the output of the key 2, radio pulses are formed with a filling frequency determined by an external generator / and a repetition frequency determined by the generator 21 21 pulses K01mmutation. These radio implants provide sensor 3. A part of the magnetic flux created by the sensor is closed through the resonator. If the frequency of the resolver is significantly different from the frequency of the oscillator 1 signal, the resonator is not excited. After the end of the excitation radio pulse, the oscillations in the winding of the sensor 3 instantaneously fade out. If the frequency of the resolver is significantly different from the frequency of the generator 1, then the magmite flow generated by sensor 3 triggers slender oscillations: in a resonator that lumps high Q, it oscillates in the L-axes between the radio stimuli and creates magnetic notoiK which, in turn, on the BcxojHT emf of the useful signal in the winding of the sensor 3. The closer the frequency of the resonator and the exciting signal, the greater the amplitude of the signal in the winding of the sensor 3 in the pauses between the excitation pulses. The signal from sensor 3, which is periodically oscillating with the frequency of the impulses of the commutadyon, is fed to the amplifier amplifier, H Ichitel 4, which is a linear amplifier for weak signals (in the pause), and for the sigal signal of the radio pulse, it is a two-way suppressor; In this way, it improves the ratio of the useful signal IK to the excitation voltage that passed through the key 2, as well as to the voltage of the transient process when switching the keys 2 5. The key 5, controlled from output 19, operates 15 out of phase with the key 2, which is controlled from Output 18 of the generator 21 commutation pulses. The signal with the frequency fi from the output of the key 5 is transmitted to one of the inputs of the mixer, while the signal of the local oscillator 10 with the frequency / 2 through the key I open sylphase with the key 5, enters

the input of the additional balanced mixer l, and to its other input a signal from the generator / frequency / is constantly post-T.-i At the output of the mixer S nprf open ;; 1 d) M key 9 will be present with the frequency fz + fi, fz- / ь

The time of occurrence of these signals at the input of the main mixer 6 corresponds to a pause between excitation waves, and if the generator frequency / corresponds to its own resonator frequency, then another output of the mixer 5 b) will present a signal with frequency fi, in this case the output of mixer 6 will be attend sigk .ly with frequencies:

(/ 2 + / i) (/ 2 -; - / i) + f, / 2 + 2f ,; (f2-fi) - /. / 2-2 / :;

(72 - /,) - f /./ 2.

The remaining components of the spectrum; will be: wherever: 1y balanced mixer. The signal with frequency / 2 will pass through the bonds; op:} a moose filter 11 tuned to the frequency / vt is amplified by amplifier 13. The amplified sigmal is detected by an amplitude detector 14, which emits a radio pulse envelope with damped, lx oscillation. The signal is further amplified by a low-frequency amplifier 15. The voltage rectified by the amplitude detector 16 is indicated by the arrow indicator 17. Thus, the signal in the device is amplified at the frequency of the signal by the booster amplifier 4, and by the heterodyne frequency 10 by the mixer 6 and amplifier 13, l at a low frequency (at the switching frequency) - amplifier 15 low frequency.

Signal amplification at three frequencies ensures a stable operation of the lobby in a large gain. The frequency conversion of the signal into the frequency of heteroD1 is carried out at any frequency signal screaming, l, therefore, it allows to expand the range of operating frequencies.

To improve the lodavlen signal of the local oscillator 10, which is lazitic for the mixer 6, the output of the alternating balanced mixer 8, which suppresses the signal of the local oscillator, included a dolollitello notch filter 7 tuned to the frequency of the local oscillator 10. Between the narrow-band filter // and the high-frequency amplifier 13 is turned on the key 12, opened by the sinal from the generator output 20 of the IMT pulses of the AI) AI. This signal is inserted into the signal from output 19 (i.e., starts later, and ends before the signal from output 19). This allows you to exclude the passage of the signal of lomekha from pre-current processes of the COM4 commutation of the keys 2 and 5 due to the shorter duration of the impulses opening the key 12, as well as to restore the signal wave to the narrow band

filter 11, which has the ability to integrate the signal arriving at its input, which leads to a decrease in the signal at the output of the detector 14 and, thus, to a decrease in the sensitivity of the device. The key 9 during the passage of the excitation radio pulses disconnects the local oscillator 10 from the mixer 8, thereby providing a better suppression of the interference signal. The device provides high sensitivity in that the amplification is carried out at three different frequencies, in addition, it has a wide frequency range from a few milogharts to tens of mega-ger, determined only by the quality of the work of balanced mixers, and allows tuning of various resonators and connections , does not require rebuilding, since when tuning resonators and links, only the frequency of the external oscillator varies.

Claims (2)

1. Petrov A.N., Shmatchenko V.D. Bandpass Electromechanical Radio Frequency Filters. Gosenergoizdat, 1961, p. 255-257. 2. The exchange of experience in radioindustry,. 12.1969, p. 62 (prototype).  2 LJ 3 S 4  L, J /and -. Bh 21