Non-interfering on-line receiver test system
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorKenneth J. Campbell
Life of this patent
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Abstract
An on-line noise figure measurement system for receivers that produces va results whether or not signals are being received. A narrow pulse having a low pulse repetition frequency and low amplitude is injected into the receiver. A processing circuit cyclically measures the output of the RF stage of the receiver to produce a ratio of two signal values. One value is measured in the absence of any signal entering the receiver while the other value is measured with only the pulse signal impressed on the receiver.
Claims5
A system for providing noise figure testing of receivers without interfering with their normal operation and providing valid results while signals are being received, the combination comprising:
- (a) a receiver including a receiving antenna, an RF amplifier, a mixer and IF amplifier stage and having a track and hold circuit connecting the output of said RF amplifier to the input of said mixer and IF amplifier stage;
- (b) signal detecting means coupled to the output of the RF stage of said receiver;
- (c) pulse signal generating means;
- (d) switching means for coupling said receiver to said receiving antenna and to said pulse generator;
- (e) sequence controller means coupled to said pulse generating means, to said switching means and to said track and hold circuit means, said sequence controller means sequentially disconnecting the antenna from said receiver and connecting said pulse signal generating means to said receiver so that signals of two different values will be detected by said detecting means;
- (f) and processing circuit means coupled to said sequence controller and to said detecting means for providing an output signal in response to the two detected values that is proportional to the noise figure of the receiver.
Dependencies are inferred from the claim text.