Miniaturized programmable attenuator

Abstract

The utility model discloses a miniaturized programmable attenuator which comprises a main body, an SMA radio frequency interface, an SMA radio frequency interface, an SMA radio frequency interface, a data / power supply interface, a signal conditioning circuit, a standing wave detection circuit and a parameter calculation circuit. A layered cavity design mode is adopted, the I / O and power supply circuit and the numerical control attenuator group are respectively arranged in different layers, and the numerical control attenuator chips of the numerical control attenuator group are respectively arranged in different cavities, so that the interference among the circuits is reduced, the programmable attenuator is small in size and good in isolation, and the service life of the programmable attenuator is prolonged. Therefore, the requirements of miniaturization and convenience in use of detection equipment of an airborne communication system in an external field are met; and the fixed attenuator is designed at the tail end of the programmable attenuator, so that the numerical control attenuator group can be well protected from being damaged by large-energy signals if the programmable attenuator is reversely connected during equipment debugging.

Description

Technical Field

[0001] The utility model relates to the technical field of attenuators, in particular to a miniaturized program-controlled attenuator. Background Art

[0002] When civil aviation, general aviation and military aircraft are undergoing first-line maintenance and inspection in the field, they need to complete the inspection tasks efficiently and locate the fault quickly and accurately when there is a fault. Therefore, the inspection equipment in the field needs to be more miniaturized to make it more efficient and quicker to use.

[0003] When testing the receiving channel performance of the airborne communication system in the field, the RF signal energy needs to have a 90dB dynamic range and be able to be reduced to below -120dBm. This requires the programmable attenuator to have good isolation to ensure that the RF signal energy has a large dynamic range and can be reduced to below the receiving sensitivity threshold of the communication system under test, thereby completing the test.

[0004] Although conventional programmable attenuators can meet the above requirements in terms of technical indicators, they are large in size and cannot meet the needs of miniaturization of field maintenance and testing equipment. This is also one of the reasons why some existing airborne communication system performance testing instruments are complex in structure, bulky and heavy, and inconvenient to carry. Utility Model Content

[0005] The purpose of the utility model is to provide a miniaturized programmable attenuator to solve the problems raised in the above background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A miniaturized programmable attenuator comprises a main body, an SMA radio frequency interface, an SMA radio frequency interface, an SMA radio frequency interface, a data / power supply interface, a signal conditioning circuit, a standing wave detection circuit and a parameter calculation circuit, wherein the SMA radio frequency interface, the SMA radio frequency interface and the SMA radio frequency interface are arranged on both sides of the main body; the data / power supply interface is embedded in the front side of the main body; the signal conditioning circuit, the standing wave detection circuit and the parameter calculation circuit are arranged inside the main body;

[0008] The SMA radio frequency interface is connected to the internal signal conditioning circuit, and the radio frequency signal is input through the SMA radio frequency interface when detecting the power, frequency and modulation degree of the airborne communication system;

[0009] The SMA radio frequency interface and the SMA radio frequency interface are connected to the internal standing wave detection circuit. When detecting the standing wave ratio of the airborne communication system, the radio frequency signal is input by the SMA radio frequency interface and output by the SMA radio frequency interface;

[0010] The data / power supply interface is connected to the internal parameter calculation circuit and is used for data communication with the outside and for supplying power to various circuits in the radio frequency analysis module.

[0011] As a further technical solution of the utility model: the main body is a 66*54*15.5mm rectangular structure with a hollow interior.

[0012] As a further technical solution of the present invention: the data / power supply interface adopts a four-core 2.54mm standard interface.

[0013] As a further technical solution of the utility model: the signal conditioning circuit is used to collect and analyze the radio frequency signal fed by the SMA radio frequency interface, and send the analysis result to the parameter calculation circuit.

[0014] As a further technical solution of the utility model: the signal conditioning circuit includes a π resistor network 1, a power divider, a π resistor network 2, a detector, an AGC, an amplifier, and a 4-way frequency shaping; wherein the π resistor network 1 receives the radio frequency signal input by the SMA radio frequency interface, and is used to attenuate the energy of the radio frequency signal; the power divider is used to divide the radio frequency signal into two paths, one path is sent to the π resistor network 2, and the other path is sent to the AGC; the π resistor network 2 is used to further attenuate the energy of the radio frequency signal, thereby adjusting the dynamic range to adapt to the input requirements; the detector 1 is used to perform envelope detection on the radio frequency signal; the AGC is used to control the energy of the radio frequency signal within a certain range; the amplifier is used to amplify the energy of the radio frequency signal to within the dynamic range received by the 4-way frequency shaping; the 4-way frequency shaping is used to down-convert the radio frequency signal to 1 / 4 times the original frequency, and shape the signal to a TTL level.

[0015] As a further technical solution of the utility model: the standing wave detection circuit is used to collect the analog effective voltage value related to the forward and reverse power of the radio frequency signal input by the SMA radio frequency interface and output by the SMA radio frequency interface, and send the result to the parameter calculation circuit; the standing wave detection circuit includes a coupling circuit, a π resistor network three, a π resistor network four, a detector two, and a detector three; wherein the coupling circuit is used to receive the radio frequency signal input by the SMA radio frequency interface and send it to the SMA radio frequency interface output, and during the transmission of the radio frequency signal, the coupled signal related to the forward power is sent to the π resistor network three, and the coupled signal related to the reverse power is sent to the π resistor network four; the π resistor network three is used to attenuate the energy of the signal related to the forward power; the π resistor network four is used to attenuate the energy of the signal related to the reverse power; the detector two is used to detect the analog voltage effective value related to the forward power; the detector three is used to detect the analog voltage effective value related to the reverse power.

[0016] As a further technical solution of the utility model: the parameter calculation circuit includes a counter group, a single-chip microcomputer, and a voltage stabilizing circuit; wherein the counter group is a 16-bit counter composed of four counters, which is used to detect the frequency of the TTL level sent by the 4-division frequency shaping; the single-chip microcomputer is used to complete the calculation of the average power, frequency, modulation degree and standing wave ratio of the RF signal, and send the parameter data through the data / power-on interface; the voltage stabilizing circuit receives the power supply voltage of the data / power supply interface 4, and is used to power each circuit of the analysis module.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] This invention adopts a layered cavity design method, in which the I / O and power supply circuits and the digital controlled attenuator group are placed in different layers respectively, and each digital controlled attenuator chip of the digital controlled attenuator group is placed in a different cavity respectively, so as to reduce the interference between the circuits, and make the program-controlled attenuator compact and have good isolation, thereby meeting the requirements of the airborne communication system for miniaturization and convenient use of detection equipment in the field; a fixed attenuator is designed at the end of the program-controlled attenuator, and if the program-controlled attenuator is connected reversely when debugging the equipment, the digital controlled attenuator group can be well protected from being damaged by a large energy signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the three-dimensional structure of a miniaturized program-controlled attenuator of the utility model;

[0020] Figure 2 This is a top view of a miniaturized programmable attenuator of the utility model;

[0021] Figure 3 This is a bottom view of a miniaturized program-controlled attenuator of the utility model;

[0022] Figure 4 It is a schematic diagram of the overall technical solution of the utility model.

[0023] In the figure: SMA RF interface 1-1, SMA RF interface 2-2, control / power supply interface-3, digital control attenuator group-4, fixed attenuator-5 and I / O and power supply circuit-6, main body-7, DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the utility model are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] Example 1, reference Figure 1-Figure 4 , including a main body 7, an SMA RF interface 1, an SMA RF interface 2, a control / power supply interface 3, a digitally controlled attenuator group 4, a fixed attenuator 5 and an I / O and power supply circuit 6; the main body 7 is a 71*27*16mm rectangular structure, and is internally divided into an upper and lower layer, wherein the upper layer is divided into four cavities and the lower layer is one cavity; the SMA RF interface 1 and the SMA RF interface 2 are placed on both sides of the main body 7; the control / power supply interface 4 is embedded in the front side of the outside of the main body 7; the digitally controlled attenuator group 4 and the fixed attenuator 5 are placed in the four cavities in the upper layer of the main body 7; the I / O and power supply circuit 6 is placed in the lower cavity inside the main body;

[0026] Embodiment 2, on the basis of embodiment 1, the SMA RF interface 1 is connected to the internal digitally controlled attenuator group 4, and the RF signal to be attenuated is input by the SMA RF interface 1; the SMA RF interface 2 is connected to the internal fixed attenuator 5, and the attenuated RF signal is output by the SMA RF interface 2; the control / power supply interface 3 adopts a ten-core 2mm standard interface, which is connected to the internal I / O and power supply circuit 6, and is used to receive external I / O signals and power various circuits in the programmable attenuator;

[0027] The working principle is as follows: The specific implementation method of applying RF signal energy to attenuate is as follows:

[0028] The carrier RF signal of the airborne communication system is fed into the digital controlled attenuator group 4 through the SMA RF interface 1, and then passes through the variable attenuation of the digital controlled attenuator chip 1, the digital controlled attenuator chip 2, and the digital controlled attenuator chip 3, and then passes through the 30dB fixed attenuation of the fixed attenuator, and finally outputted through the SMA RF interface 2. The variable attenuation is controlled by the external I / O signal of the programmable attenuator through the control / power supply 3 interface. Pin 1 of the control / power supply interface 3 controls the 31.75dB variable attenuation of the digital controlled attenuator chip 1, pin 2 of the control / interface 3 controls the 31.75dB variable attenuation of the digital controlled attenuator chip 2, and pins 3, 4, 5, 6, 7, 8, and 9 of the control / interface 3 respectively control the 16dB, 8dB, 4dB, 2dB, 1dB, 0.5dB, and 0.25dB variable attenuation of the digital controlled attenuator chip 3. By providing the corresponding external I / O control signal through the host computer, the RF signal can be attenuated with a step of 0.25dB and a dynamic range of 95.25dB. The fixed attenuation and variable attenuation can achieve a cumulative energy attenuation of 125.25dB.

[0029] For example, when 100dB energy attenuation is required, a host computer that can provide external I / O signals is connected through control / interface 3, so that pins 1, 2, 4, 5, and 7 of control / interface 3 are 3.3V high level, and pins 3, 6, 8, and 9 of control / interface 3 are 0V low level. At this time, the variable attenuation of digital controlled attenuators 1, 2, and 3 is 70dB, and the fixed attenuation of the fixed attenuator is 30dB. The two together complete 100dB energy attenuation of the RF signal.

[0030] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0031] In addition, it should be understood that although the present specification is described in terms of implementation modes, not every implementation mode contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment have also been appropriately combined to form other implementation modes that those skilled in the art can understand.

Claims

1. A miniaturized programmable attenuator, comprising a main body, a first SMA radio frequency interface, a second SMA radio frequency interface, a control / power supply interface, a digitally controlled attenuator group, a fixed attenuator, and an I / O and power supply circuit, characterized in that: The interior of the main body is divided into two layers, the upper layer is divided into four cavities, and the lower layer is one cavity; the SMA RF interface 1 and SMA RF interface 2 are placed on both sides of the main body; the control / power supply interface is embedded in the front side of the main body; the digital control attenuator group and the fixed attenuator are placed in the four cavities in the upper layer of the main body; the I / O and power supply circuits are placed in the lower cavity of the main body; The SMA RF interface 1 is connected to the internal digitally controlled attenuator group, and the RF signal to be attenuated is input through the SMA RF interface 1; The SMA radio frequency interface 2 is connected to the internal fixed attenuator, and the attenuated radio frequency signal is output by the SMA radio frequency interface 2; The control / power supply interface is connected to the internal I / O and power supply circuits and is used to receive external I / O signals and power supply signals.

2. A miniaturized programmable attenuator according to claim 1, characterized in that: The main body is a 71*27*16mm rectangular structure.

3. A miniaturized programmable attenuator according to claim 1, characterized in that: The control / power supply interface adopts a ten-core 2mm standard interface.

4. A miniaturized programmable attenuator according to claim 1, characterized in that: The digital controlled attenuator group is composed of three digital controlled attenuator chips with variable attenuation gears of 16dB, 8dB, 4dB, 2dB, 1dB, 0.5dB and 0.25dB, and is connected to the I / O and power supply circuits.

5. A miniaturized programmable attenuator according to claim 4, characterized in that: The digitally controlled attenuator chip 1 controls the attenuation of 31.75dB RF signal energy through pin 1 of the control / power interface; the digitally controlled attenuator chip 2 controls the attenuation of 31.75dB RF signal energy through pin 2 of the control / power interface; the digitally controlled attenuator chip controls the attenuation of 16dB RF signal energy through pin 3 of the control / power interface, controls the attenuation of 8dB RF signal energy through pin 4 of the control / power interface, controls the attenuation of 4dB RF signal energy through pin 5 of the control / power interface, controls the attenuation of 2dB RF signal energy through pin 6 of the control / power interface, controls the attenuation of 1dB RF signal energy through pin 7 of the control / power interface, controls the attenuation of 0.5dB RF signal energy through pin 8 of the control / power interface, and controls the attenuation of 0.25dB RF signal energy through pin 9 of the control / power interface.

6. A miniaturized programmable attenuator according to claim 1, characterized in that: The fixed attenuator is a 30dB fixed attenuator, which is connected to the digital controlled attenuator group.

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