| Instrument Landing System has been widely used in our military and civil landing, the imported stimulator of instrument landing has not met the requirement of the production for current airborne equipment and ramp test. Under this situation, we give the development requirement of stimulator for instrument landing china-made in this paper.The stimulator of Instrument Landing is a kind of amplitude-modulated signal source, for the signal source, it provides the higher requirement for carrier frequency and modulation signal. In this paper, based on reading deeply, studying the relevant document at home and onboard, through emulating, testing, we determine that the signal source of carrier-wave adopts locking-phase frequency synthesizing technology in dual-module frequency-dividing, the modulation signal adopts software method as well as AD834, etc circuit to realize the technical scheme in linear amplitude-modulated, so the circuit design of stimulator for Instrument Landing can be carried out.In the design of stimulator, according to the interference, output accuracy can not meet the requirement of EMC occurred in development, we discussed the restrain electromagnetic interference in two ways: shielding and grounding. In part of shielding, we discuss the principle of shielding, the shielding material choice of metal plate and performance calculation as well as shielding cable selection and grounding mode. In part of grounding, we discuss the mode selection of signal grounding, the interference principle of ground and the measures suppressing ground interference. Through selecting proper grounding mode and anti-interference measure, it can suppress the interference resulted in common impedance.
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