초록 ▼

Apparatus and methods for combining incoherent signals having different carrier frequencies but a common modulation to obtain a coherent summation of the modulations of such signals are described. The apparatus comprises adaptive means of changing the carrier frequencies and corresponding phases of

Apparatus and methods for combining incoherent signals having different carrier frequencies but a common modulation to obtain a coherent summation of the modulations of such signals are described. The apparatus comprises adaptive means of changing the carrier frequencies and corresponding phases of various signals to a common carrier frequency and a common phase, thus enabling the coherent summation of the common modulation and enhancing, thereby, the level of received information content. When the incoherent signals are transponder-signals, radiated from an object or platform in response to a modulated interrogating signal, and are obtained by different frequency offsets from the interrogating signal carrier frequency, the particular offset frequencies being unique to that object or platform, the ability combining of modulations coherently provides a means of unique identification of the object or platform.

대표청구항 ▼

An adaptive closed-loop controlled, signal combining system for multi-carrier-frequency signals, each having the same modulation, enhancing thereby the signal-to-noise ratio of the combined signal with respect to that of any individual signal comprising: (a) a sensor that receives signals radiated f

An adaptive closed-loop controlled, signal combining system for multi-carrier-frequency signals, each having the same modulation, enhancing thereby the signal-to-noise ratio of the combined signal with respect to that of any individual signal comprising: (a) a sensor that receives signals radiated from a plurality of sources, each signal having a different carrier frequency, but a common modulation; (b) a plurality of bandpass filters, same in number as the number of said sources, each filter having an input and an output, the input of each filter being connected to said sensor such that the output of each filter corresponds to the radiated signal from only one of said sources; (c) means for changing, automatically, said carrier frequency and the carrier phase of the signal at the output of each said filter, to a common carrier frequency and a common phase without affecting the modulation; and (d) means for summing the signal at each filter line after its carrier frequency and phase are changed to a common carrier frequency and a common phase to effect coherent addition of modulation of each of said signals.