Patent ID: 6559754
Filing Date: 2003-05-06
Classification: G06K

Abstract:
A method for the contactless transmission of data (DA) from a data carrier (D) to a write/read station (1), whereinthe write/read station (1) generates a carrier signal (CS) and the generated carrier signal (CS) is applied to contactless operative transmitter means (20) of the write/read station (1), wherein a carrier signal (CS) is obtained in the data carrier (D) by means of contactless operative transmitter means (40) of the data carrier (D) which are coupled to the transmitter means (20) of the write/read station (1) in a contactless manner, wherein load modulation of the carrier signal (CS) is performed by means of one auxiliary carrier signal (SCS1) in a transmission mode for the transmission of a data block (DB) from the data carrier (D) to the write/read station (1), wherein the carrier signal (CSE) load modulated by means of the one auxiliary carrier signal (SCS1) is demodulated by means of demodulation means (25) in the write/read station in order to obtain the transmitted data block (DB), wherein a test is performed in the write/read station (1) in order to determine whether disturbances occur in the signal path beyond the demodulation means (25), and wherein control information is generated upon detection of disturbances, characterized in that at least one transmission mode data block (MDB1, MDB2, MDB3) is generated as control information, that the transmission mode data block (MDB1, MDB2, MDB3) is transmitted to the data carrier (D), that the transmitted transmission mode data block (MDB1, MDB2, MDB3) is evaluated in the data carrier (D), that, in conformity with the evaluation of the transmitted transmission mode data block (MDB1, MDB2, MDB3), the data carrier (D) is controlled to an other transmission mode in which, in order to transmit a data block (DB) from the data carrier (D) to the write/read station (1), load modulation of the carrier signal (CS) is performed by means of at least one other auxiliary carrier signal (SCS2), the at least one frequency (f2) of the at least one other auxiliary carrier signal (SCS2) and the frequency (f1) of the one auxiliary carrier signal (SCS1) having different values, that, during the testing as to whether disturbances occur in the signal path beyond the demodulation means (25), a test is performed so as to determine whether the disturbances are due to an error occurring during the load modulation of the carrier signal (CS) by means of the one auxiliary carrier signal (SCS1), and that, in the case of a positive result of this test, a transmission mode data block (MDB2, MDB3) associated with this test result is generated, transmitted to the data carrier (D) and evaluated in the data carrier (D).