Coded coherent transponder

Claim 2

A coded coherent transponder with a receiver and a transmitter for receiving an interrogation signal and transmitting a coherent response including predetermined coded information, said transponder including means for introducing a predetermined coded complex phase shift into the coherent response representative of a simultaneous plurality of Doppler frequency components.

Claim 3

A coded coherent transponder as claimed in claim 1 wherein the transponder further includes means for introducing a predetermined amplitude shift into the coherent response.

Claim 4

A coded coherent transponder with a receiver and a transmitter for receiving an interrogation signal and transmitting a coherent response including predetermined coded information, said transponder including means for introducing a predetermined coded amplitude shift into the coherent response representative of a simultaneous plurality of Doppler frequency components.

Claim 5

A coded coherent transponder with a receiver and a transmitter for receiving an interrogation signal and transmitting a coherent response including predetermined coded information, said transponder including means for introducing a predetermined coded amplitude shift into the coherent response representative of a simultaneous plurality of Doppler frequency components.

Claim 6

A coded coherent transponder comprising: (a) a receiver for receiving an interrogation signal from a remotely positioned, pulsed radar; (b) delay means coupled to said receiver for delaying the interrogation signal; (c) phase shifting means coupled to said delay means for introducing a predetermined coded complex phase shift into the interrogation signal representative of a simultaneous plurality of Doppler frequency components; and (d) a transmitter coupled to receive the delayed and phase shift coded signal for transmitting a coherent coded response to the remotely positioned, pulsed radar, said delay means introducing sufficient delay to allow the reception of a substantially complete interrogation signal prior to transmission of the response.

Claim 7

A coded coherent transponder comprising: (a) a receiver for receiving an interrogation signal from a remotely positioned, pulsed radar; (b) delay means coupled to said receiver for delaying the interrogation signal; (c) phase shifting means coupled to said delay means for introducing a predetermined coded complex phase shift into the interrogation signal representative of a simultaneous plurality of Doppler frequency components; and (d) a transmitter coupled to receive the delayed and phase shift coded signal for transmitting a coherent coded response to the remotely positioned, pulsed radar, said delay means introducing sufficient delay to allow the reception of a substantially complete interrogation signal prior to transmission of the response.

Claim 8

A coded coherent transponder as claimed in claim 4 wherein the phase shifting means includes circuitry for dividing the interrogation signal into in-phase and quadrature components, first and second attenuators coupled to operate on the in-phase and quadrature components, respectively, in response to a code applied thereto, and circuitry for recombining the components into a resultant, phase shift coded signal.

Claim 9

A coded coherent transponder as claimed in claim 5 wherein each of the first and second attenuators includes a double-balanced diode mixer.

Claim 10

In a coherent transponder including a receiver and a transmitter for receiving an interrogation signal and transmitting a coherent response, a method of coding the response to represent predetermined data, said method comprising the steps of: (a) receiving the interrogation signal; (b) phase modulating the receiver signal in accordance with a predetermined code by introducing a predetermined complex phase shift into the signal to represent a plurality of simultaneous predetermined responses; and (c) transmitting the modulated signal.

Claim 11

In a coherent transponder including a receiver and a transmitter for receiving an interrogation signal and transmitting a coherent response, a method of coding the response to represent predetermined data, said method comprising the steps of: (a) receiving the interrogation signal; (b) phase modulating the receiver signal in accordance with a predetermined code by introducing a predetermined complex phase shift into the signal to represent a plurality of simultaneous predetermined responses; and (c) transmitting the modulated signal.