A measuring bridge (1) provides a first matching pad (2), a second matching pad (3) and a third matching pad (4), wherein all matching pads (2, 3, 4) comprise at least three resistors (2.sub.1, 2.sub.2, 2.sub.3, 3.sub.1, 3.sub.2, 3.sub.3, 4.sub.1, 4.sub.2, 4.sub.3) which are arranged in a T-structure. A second resistor (3.sub.2) of the second matching pad (3) is connected to a second resistor (2.sub.2) of the first matching pad (2), and a third resistor (4.sub.3) of the third matching pad (4) is connected to a third resistor (2.sub.3) of the first matching pad (2). A second resistor (4.sub.2) of the third matching pad (4) can be connected to a device under test (7). A third resistor (3.sub.3) of the second matching pad (3) can be connected to a calibration standard (5), and a first resistor (3.sub.1, 4.sub.1) of the second and the third matching pad (3, 4) are connected in each case to a signal input of an element (11) which suppresses a common-mode component on its two signal inputs.

A measuring bridge (1) provides a first matching pad (2), a second matching pad (3) and a third matching pad (4), wherein all matching pads (2, 3, 4) comprise at least three resistors (2.sub.1, 2.sub.2, 2.sub.3, 3.sub.1, 3.sub.2, 3.sub.3, 4.sub.1, 4.sub.2, 4.sub.3) which are arranged in a T-structure. A second resistor (3.sub.2) of the second matching pad (3) is connected to a second resistor (2.sub.2) of the first matching pad (2), and a third resistor (4.sub.3) of the third matching pad (4) is connected to a third resistor (2.sub.3) of the first matching pad (2). A second resistor (4.sub.2) of the third matching pad (4) can be connected to a device under test (7). A third resistor (3.sub.3) of the second matching pad (3) can be connected to a calibration standard (5), and a first resistor (3.sub.1, 4.sub.1) of the second and the third matching pad (3, 4) are connected in each case to a signal input of an element (11) which suppresses a common-mode component on its two signal inputs.

A measurement accessory device connectable to a measurement apparatus or to a device under test wherein the measurement accessory device comprises means for providing characteristic data of said measurement accessory device in machine readable form used by said measurement apparatus during measurement of said device under test.

A measurement accessory device connectable to a measurement apparatus or to a device under test wherein the measurement accessory device comprises means for providing characteristic data of said measurement accessory device in machine readable form used by said measurement apparatus during measurement of said device under test.

The device for the impedance-based probing of materials described herein comprises a two-dimensional array of coils (1) and a measurement unit (4) adapted to determine, for each coil (1), a parameter indicative of its impedance. A pulse generator (3) is able to generate current pulses in each coil (1). The circuitry drives and senses the coil array through row and column lines (rp1 . . . rpN1, cp1 . . . cpN2, c21 . . . csN2) in order to minimize the number of required components. The device can, in particular, be used for probing concrete.

An impedance control device for tuning a device under test comprising: a first terminal port arranged for connecting a device under test, a second terminal port arranged for connecting a termination, a first signal path for a signal travelling between the first and the second terminal port, first coupling means arranged for picking up a part of the signal travelling in the first signal path, a second signal path arranged for receiving the part of the signal from the first coupling means, said second signal path comprising a correction circuit for adapting as a function of frequency the amplitude and phase of the received part of the signal, second coupling means arranged for coupling back into the first signal path an adapted signal outputted by the correction circuit, and an attenuator and phase shifter for applying attenuation and phase shifting on the signals travelling between the first and the second terminal port.

A device and method for testing a mixer. For testing, signals having essentially the same frequency are applied to local oscillator (LO) and radio frequency (RF) inputs of the mixer. The signals phase-shifted with respect to each other and an output of the mixer is measured to provide a result.

A device and method for testing a mixer. For testing, signals having essentially the same frequency are applied to local oscillator (LO) and radio frequency (RF) inputs of the mixer. The signals phase-shifted with respect to each other and an output of the mixer is measured to provide a result.

A data carrier 2 is provided with a comparator 41, a capacitor 42, a comparator operation adjustment resistor 43, a resistance voltage divider circuit 44 and a reactive-current resistor 45. The capacitor 42 is disposed between the cathode of a photo-diode (PD) 21 and the minus input terminal of the comparator 41. The comparator operation adjustment resistor 43 is disposed between the plus terminal of a primary battery 271 and the minus input terminal of the comparator 41. The resistance voltage divider circuit 44 is constituted by a series connection of voltage dividing resistors 441 and 442. One end of the resistance voltage divider circuit 44 is connected to the plus terminal of the primary battery 271. The junction between the voltage division resistor 441 and the other voltage division resistor 442 is connected to the plus input terminal of the comparator 41.

A method for wirelessly calibrating/testing RF and digital components of a multi-antenna device under test includes the step of wirelessly transmitting a first signaling information between the device under test and a device tester, the first signaling information indicating a calibration request, wherein the first signaling information is transmitted by the device under test or the device tester. Further, the method includes the step of estimating, in response to the first signaling information, channel transfer function matrices between active antenna ports/RF ports of the device under test and antenna ports of the device tester using reference signals wirelessly transmitted between the device tester and the device under test or vice versa.