EA036811B1 - Frequency isolation filter - Google Patents

Abstract

The invention relates to radio engineering and can be used in radio engineering equipment, in particular, in receivers and transmitters for decoupling the transmitter output and the receiver input when operating to a single antenna with automatic retuning of the receiver and the transmitter to the required frequency within the operating frequency band. The frequency isolation filter consists of resonators including an external conductor as a case, and internal conductors in the form of rods interconnected using inductive and capacitive couplings, and retuning elements made as a drive. First ends of internal conductors are secured on the case, their second ends form capacitors including a mobile part and a fixed part. The drive comprises a control board for automatic filter retuning; a limit switch intended for counting the number of steps of the stepping motor when calibrating the filter; a stepping motor ensuring the precise positioning and discrete angular displacement of variable capacitors mobile parts; a pinion located on the motor shaft and transmitting the torque to a first gearbox, which is kinematically connected to the shaft, transmitting the torque to a second gearbox and a gearing that transmits the torques to the mobile parts of the variable capacitors secured on the gears. The technical results is improving the operational capabilities of the frequency isolation filter due to automatic frequency retuning with precise positioning of resonators.

Description

The invention relates to radio engineering and can be used in the equipment of radio engineering products, namely in transceiver devices for decoupling the transmitter output and the receiver input when operating on one antenna with automatic tuning of the receiver and transmitter to the required frequency in the operating frequency range.

Known microwave filter with mechanical tuning (D.L. Mattey, L. Young, EMT Jones. Microwave filters, matching circuits and communication circuits, vol. 2, translated from English, ed. Communication M. 1972. , p. 421), which includes resonators, in which one end is open, the other is short-circuited, the restructuring of which is carried out by smooth movement back and forth of the round central conductor. The resonators are inductively coupled to each other.

The disadvantages of the filter are the lack of conjugation between adjacent resonators, which does not allow simultaneous tuning of the filters to a given frequency and requires a separate manual tuning of each resonator; thus, a large amount of time must be spent on tuning and ensuring high accuracy of resonator positioning, which degrades the filter's performance.

Closest to the proposed invention is a high-frequency comb filter (patent US 5389903, IPC Н01Р 1/205, published 02.14.1995), taken as a prototype, including resonators consisting of an outer conductor in the form of a housing and internal conductors in the form of rods, some ends of which are fixed on the body, and the other ends form capacitors having inductive and capacitive couplings, and adjustment elements.

The disadvantage of the prototype is that this filter design provides for frequency adjustment by adjusting screws of each resonator separately, thereby increasing the tuning time, and there is no possibility of simultaneous restructuring of all filter resonators from one frequency to another, because there is no conjugation between adjacent resonators. To rebuild the filter to a different frequency, it is necessary to manually turn the adjusting screws separately for each of the resonators until a given frequency is reached, which is time-consuming and thereby degrades the filter's performance.

The object of the invention is to improve the performance of the frequency isolation filter through automatic frequency tuning with precise positioning of the resonators.

The problem is solved by the fact that the filter consists of resonators consisting of an external conductor in the form of a housing and internal conductors in the form of rods, interconnected by inductive and capacitive couplings, and adjustment elements made in the form of a drive. Some ends of the inner conductors are fixed to the body, the other ends form capacitors, consisting of a movable part (rotor) and a stationary part (stator). The drive includes a control board for automatic filter adjustment, a limit switch used to count the number of steps of a stepper motor, a stepper motor that provides precise positioning and discrete angular movement of the moving parts of variable capacitors, a gear located on the motor shaft and transmitting torque to the first gearbox, kinematically connected with a shaft that transmits torque to the second gearbox and a gear train that transmits torques to the movable parts of variable capacitors attached to the gear wheels of the gear train.

The invention is illustrated in the figures, where FIG. 1 shows a front view, FIG. 2 is a top view.

The frequency decoupling filter is made in a two-row arrangement and is located in the housing 1. Each row consists of resonators 2, including rods 3, movable parts 4 of variable capacitors and fixed parts 5 of variable capacitors, and adjustment elements in the form of a drive. The resonators 2 are interconnected by inductive and capacitive couplings, while an element in the form of a high-resistance conductor is connected to one of the extreme rods 3 of the resonators 2 to provide communication between the receiving path and the transmitting path (not shown in the figures), which can be made according to the author's certificate SU 1786550. The drive includes a stepper motor 6 for adjusting the filter to its operating frequency, gear 7 and the first gearbox 8, kinematically connected to the shaft 9, the second gearbox 10, transmitting the rotational force from the shaft 9 by means of the gear transmission 11 to the movable parts 4 of the variable capacitors containers, which are connected to the gear wheels of the gear transmission 11, for example, by means of a sleeve. The commands to tune the filter frequency are sent to the stepper motor 6 from the control board 12. The limit switch, consisting of a cam 13 fixed on the moving part 4 of the capacitor, for example, by means of a sleeve, and contact 14, serves to count the number of steps of the stepper motor 6 during calibration filter.

The filter works as follows.

Each frequency corresponds to a certain number of steps of the stepper motor 6 from the contact 14 of the limit switch. Before starting work, the filter is calibrated to record in the memory of the control board 12 the number of steps of the stepper motor 6 required to adjust all the specified operating frequencies. With the discrete movement of the stepper motor 6, the cam 13 of the limit switch, fixed on the movable part 4 of the extreme variable capacitor, rotates

- 1,036811 containers. When the set frequency is adjusted, the cam 13 of the limit switch closes the contact 14 of the limit switch, and a signal is sent to the control board 12, where the number of steps of the stepper motor 6 required to set the set frequency is recorded in memory.

During operation of the filter, when tuning to a certain frequency, a command is sent from the control board 12 to the stepping motor 6. The stepping motor 6 rotates through a certain angle corresponding to the number of steps recorded in the memory of the control board 12. The shaft of the stepping motor 6 moves the gear 7 fixed to it, driving through the first gearbox 8 shaft 9, which transmits torque to the second gearbox 10. The second gearbox 10, located on the central resonator 2 for uniform distribution of the power flow of rotation of the gear wheels on the left and right shoulder of the gear transmission 11, and, accordingly, reduce the load to the gear train 11, through its drive transmits the torque to the gear wheels of the gear train 11 to the left and right shoulder simultaneously. The toothed wheels of the gear transmission 11 have the same number of teeth with the drive of the reducer 10, which does not change the rotation speed and allows moving simultaneously with the same angular speed the movable parts 4 of variable capacitors. The gears of the gear transmission 11 during rotation move the movable parts 4 of variable capacitors, which leads to a change in the overlap area between the plates of the movable parts 4 and the stationary parts 5 of the capacitors, and thereby sets the filter to a given frequency.

Claims (1)

CLAIM Frequency decoupling filter, consisting of resonators, including an outer conductor in the form of a body and inner conductors in the form of rods, one ends of which are fixed on the body, and the other ends form capacitors having inductive and capacitive couplings among themselves, and adjustment elements, characterized in that the adjustment elements are made in the form of a drive, kinematically connected with the parts of the resonators that form the capacitors, while the drive is made in the form of a stepping motor with a control board and a limit switch, kinematically connected through a gear and a first gearbox with a shaft kinematically connected with a second gearbox located on the central resonator, and a gear train, to the wheels of which are attached parts of the resonators, forming a capacitor.