Radio altitude signal simulator assembly based on surface acoustic wave delay lines

Abstract

The invention discloses a radio altitude signal simulator assembly based on surface acoustic wave delay lines, relating to an avionic device detection instrument, in particular to a signal simulator assembly of a radio altimeter detector. According to the invention, a plurality of delay lines are arranged and a numerical-control electrically controlled attenuator is additionally arranged; the radio altitude signal simulator assembly also comprises a single-pole multi-throw switch and a single-pole double-throw switch, wherein the single-pole multi-throw switch is used for selecting to switch a radio frequency signal to pass different delay lines; the single-pole double-throw switch is used for selecting to switch a radio frequency signal to pass a delay line path or pass a straight channel path which bypasses a frequency-conversion filtering element and component path; and the single-pole multi-throw switch, the single-pole double-throw switch and the numerical-control electrically controlled attenuator are respectively electrically connected with a micro control unit. According to the radio altitude signal simulator assembly disclosed by the invention, due to adoption of modularized design, the plurality of delay lines which are capable of carrying out different time delays are arranged on one set of assembly, the single-pole multi-throw switch is controlled by the MCU micro control unit to realize selection and switching. Compared with the prior art, the radio altitude signal simulator assembly has the advantages of improving the detection efficiency and realizing the automation because programmed automatic control and switchover can be carried out.

Description

technical field [0001] The invention relates to an avionics testing instrument, in particular to a signal simulator component of a radio altimeter testing instrument. Background technique [0002] The radio altimeter is an airborne radio device used to measure the vertical distance from the aircraft to the ground, and is one of the important aircraft instruments. It consists of transmitters, receivers and displays. It emits radio waves to the ground, and after being reflected by the ground, it is received and the flight altitude can be calculated. [0003] The instrument that detects the radio altimeter above is called a radio altimeter detector, and a very important part of it is the signal simulator component, whose function is to perform radio frequency delay and radio frequency attenuation processing on the signal emitted by the radio altimeter , and then fed back to the reception of the radio altimeter to simulate the situation in which the radio is transmitted to the...

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Problems solved by technology

[0004] Traditional radio altimeter detectors use signal simulator components, including circuits composed of attenuators, frequency converters, filters, delay lines and other components connected. Each signal simulator uses the above-mentioned various components with fixed specifications. Only one height value can be simulated. Therefore, during the detection process, the signal simulator needs to be replaced continuously to perform different degrees of signal processing on the radio frequency signal and simulate different heights. For example, when the simulated height is 500 meters, you must use For a signal simulator with a delay time of 3333ns, when the simulated height is 5000 meters, another dedicated signal simulator with a corresponding delay time of 33333ns must be added, which leads to defects such as cumbersome detection operations, low efficiency, and large errors; in addition , the delay line used in the traditional signal simulator is coaxial cable or optical cable, which has the problems of low delay accuracy, large volume and weight, and inconvenient use, which makes this kind of signal simulator unable to be integrated in the comprehensive test equipment

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