초록 ▼

The ITAT technique, embodied in ITAT hardware, provides a means to add additional operating modes to interrogator-transponder (beacon) systems in a relatively simple and economical manner. The technique permits the adding of special modulation to the normal pulse-coded transmissions for the purpose

The ITAT technique, embodied in ITAT hardware, provides a means to add additional operating modes to interrogator-transponder (beacon) systems in a relatively simple and economical manner. The technique permits the adding of special modulation to the normal pulse-coded transmissions for the purpose of providing a security identification code, or a digital wavefore enabling high processing gain, or both. Two similarly designed ITAT units are required; one for interrogator systems, and one for transponder systems. Both units simply connect between the respective system units and the system antennas. The ITAT units operate in two modes; “Normal”and “ITAT.”In the normal mode, the units do not interfere with operation of the transponder-interrogator (beacon) system. In the ITAT mode, the units suppress the beacon system operating range by introducing attenuation between the interrogator unit (or transponder unit) and the antenna. In effect, normal operation is blocked during ITAT operation. In place of normal operation, the ITAT unit specially-modulates interrogator pulse-coded emissions to add special ITAT modulation. The ITAT receiver collocated with transponders detects and decodes ITAT interrogations and passes the pulse-code information to the transponder. When the transponder replies, ITAT modulation is added to the transmission. The ITAT receiver at the interrogator unit receives ITAT-modulated replies, decodes the information, and passes the reply code signals to the interrogator unit.

대표청구항 ▼

In an interrogator-transponder beacon system having an interrogator cooperating with an antenna and a transponder cooperating with an antenna, the improvement comprising an identification technique (ITAT) comprising an interrogator add-on unit coupled between the interrogator and its antenna, and a

In an interrogator-transponder beacon system having an interrogator cooperating with an antenna and a transponder cooperating with an antenna, the improvement comprising an identification technique (ITAT) comprising an interrogator add-on unit coupled between the interrogator and its antenna, and a transponder add-on unit coupled between the transponder and its antenna; wherein said interrogator add-on unit comprises control means including means to manually select either a normal mode of operation or an ITAT mode; apparatus effective during the ITAT mode which includes means to add special modulation to an interrogator output radio frequency signal, and means to pass the interrogator signal with said special modulation to the interrogator antenna; wherein said transponder add-on unit includes control means to select either a normal mode or an ITAT mode, and apparatus effective during the ITAT mode which includes means to route the interrogation signal received at the transponder unit to an ITAT receiver, means to detect the ITAT information, means to generate a normal interrogation which is forwarded to the transponder, which in a normal manner generates a reply, means to add special modulation to the transponder output radio frequency signal, and means to pass the transponder signal with said special modulation to the transponder antenna; wherein said interrogator add-on unit further includes means to route the transponder reply received at the interrogator antenna to an ITAT receiver, means to detect the ITAT information, and means to generate a normal transponder reply which is forwarded to the interrogator.