Electricity: measuring and testing – Fault detecting in electric circuits and of electric components
Reexamination Certificate
1999-08-18
2001-08-14
Brown, Glenn W. (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
C340S010100, C340S010400, C340S010420, C340S870310
Reexamination Certificate
active
06275043
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a test device which is arranged to carry out at least one test operation on a module which is constructed for use in conjunction with a data carrier intended for contactless communication and includes an integrated component, two module terminals for connection to two transmission means terminals, two test terminals, each of which can be brought into contact with a module terminal of a module to be tested, is provided with a carrier signal generator whereby a carrier signal can be generated, and includes a signal path which is situated between the carrier signal generator and at least one test terminal and via which a test signal, corresponding to a carrier signal output by the carrier signal generator, can be applied to the at least one test terminal, the load modulation means which are included in the integrated component of the module to be tested being capable of load modulating the test signal when module terminals of a module to be tested are in contact with the test terminals.
The invention further relates to a method of manufacturing a module according to the preamble of Claim
6
.
2. Related Art
A test device of the kind set forth in the first paragraph was developed and marketed by applicant so that it is known. The known test device essentially consists of a test station, which includes the carrier signal generator, of a first transmission coil which is conductively connected to the test station, and of a second transmission coil which is inductively coupled to the first transmission coil but is not conductively connected thereto, the coil ends of said second transmission coil being connected to two test terminals of the test device via comparatively long leads. Thus, in the signal path between the carrier signal generator and the test terminals in the known test device there are inserted two transmission coils which are only inductively coupled to one another in order to apply the test signal, corresponding to the carrier signal generated by the carrier signal generator, to the test terminals so that no conductive connection is provided between the carrier signal generator and the test terminals. Consequently, the known test device is suitable only for testing the digital functionality of a module only, i.e. for testing whether digital data can be correctly transmitted from a module to the test device. A test of this kind may yield a positive result, even though other important analog characteristic values of a module do not lie within a range required for correct operation of such a module; consequently, faults could occur during operation after incorporation of such a module in a data carrier or it may be that correct operation cannot be achieved. The known test device, therefore, offers only limited possibilities for testing.
SUMMARY OF THE INVENTION
It is an object of the invention to mitigate or even eliminate the described limitations and problems and to realize an improved test device which offers significantly enhanced possibilities for testing. It is a further object of the invention to improve the method according to preamble of Claim
6
in order to enhance the certainty that the modules manufactured by the improved method do not include disadvantageous faults. In order to achieve this object, a test device of the kind set forth in the first paragraph according to the invention is characterized in that the signal path is constructed so as to be conductive, that an impedance is included in the signal path, directly ahead of at least one test terminal, and that at least one detection device is connected to at least one test terminal, which detection device is arranged to determine, while utilizing the test signal that can be applied to the at least one test terminal, an analog characteristic value of a module to be tested which is in contact with the test terminals by way of its module terminals.
In order to achieve the afore mentioned object, a method according to the preamble of Claim
6
is characterized according to the invention as disclosed in the characterizing part of Claim
6
.
Using only comparatively few additional means, the steps according to the invention simply ensure that not only the digital functionality of a module can be tested, i.e. the correct operation of the logic section, the digital section and the storage section of a module, but also at least one particularly important analog characteristic value of a module. The testing of the functionality of a module is so important because the knowing that the functionality of a module is correct prior to building into or use in a data carrier is important because the faulty module can then be rejected in the case of a negative test result, thus avoiding the production of a faulty data carrier.
It has been found that for a test device and a method according to the invention it is very advantageous to take also the steps disclosed in Claim
2
and Claim
6
, respectively. The testing of the input capacitance of a module constitutes a particularly important step during the testing of the correct functionality of a module because, after the building in of a module into a data carrier, the input capacitance of a module forms a parallel resonant circuit, for example in conjunction with a data carrier transmission coil and the resonance frequency of said circuit has to lie in an exactly defined frequency range so as to ensure optimum data transmission.
A particularly simple and reliable embodiment of a test device and a method have the characteristics disclosed in Claim
3
and Claim
8
respectively.
It has also proved to be very advantageous when additionally the steps disclosed in Claim
4
and Claim
9
, respectively, are taken to a test device and a method according to the invention. The testing of the modulation index that can be achieved by means of a module during load modulation also constitutes a very important step for the testing of the correct functionality of a module. This is because error-free and perfect data transmission is not ensured when the modulation index is too low whereas the load modulation means could cause excessive power consumption in a data carrier in the case of a modulation index which is too high; this is an important aspect notably in the case of so-called passive data carriers because such passive data carriers derive the required power from the carrier signal transmitted to such a data carrier.
The foregoing and further aspects of the invention will become apparent from the embodiment which is described hereinafter.
REFERENCES:
patent: 5345231 (1994-09-01), Koo et al.
patent: 6028503 (2000-02-01), Preishuberpflugl et al.
patent: 6091342 (2000-07-01), Janesch et al.
patent: 6097278 (2000-08-01), Arnold et al.
patent: 6112275 (2000-08-01), Curry et al.
patent: 0845751A1 (1998-06-01), None
Mühlberger Andreas
Vorreiter Johann
Brown Glenn W.
Hamdan Wasseem H.
U.S. Philips Corporation
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