Abstract: The present invention relates to a measurement system and method for analysing, and characterising, the behaviour of a high frequency device, commonly referred to in the art as a device under test (or DUT) at relatively high power levels. Such devices may for example need to be analysed when designing devices or designing circuits utilising such devices, for use in high power (large signal) high frequency amplifiers, such as an amplifier for use in a mobile telephone network or other telecommunications-related base-station. The measurement apparatus for measuring the response of an electronic device to a high frequency input signal includes an active load-pull circuit connectable in use to an electronic device to be measured. The active load-pull circuit includes a passive load-pull device.

Abstract: A method of fabricating a bone substitute material comprises the steps of providing a foam material (3) having an open cell structure, distorting the shape of the foam material (3) and holding the material in a distorted shape, coating the walls of the cells of the foam material with a ceramic slip (5), removing the foam material, and sintering the ceramic slip to form a bone substitute material that is approximately a positive image of the distorted foam material (3). In another method, a granular bone material is formed from a multiplicity of pieces of foam that are not distorted.

Abstract: An analyser for measuring the response of an electronic device (DUT 206) to an RF input signal from a signal generator 240a is described. An active load pull circuit 201 is connected to the DUT 206, which receives an output signal from the DUT 206 and then feeds a modified signal back to the DUT 206. The signal is modified by a signal processing circuit 237 in view of input signals x, y to control the magnitude gain and phase change effected by the feedback circuit 237. Thus, positive feedback loops are avoided and better control of the analyser is permitted. A network analyser, or other signal measuring device 242, logs the waveforms (from which s-parameters derived) observed at ports of the DUT 206, thereby allowing the behaviour of the DUT 206 under various load conditions to be analysed.

Abstract: An analyzer for measuring the response of an electronic device (DUT 206) to an RF input signal from a signal generator (240a) is described. An active load pull circuit (201) is connected to the DUT 206, which receives an output signal from the DUT 206 and then feeds a modified signal back to the DUT 206. The signal is modified by a signal processing circuit (237) in view of input signals x, y to control the magnitude gain and phase change effected by the feedback circuit (237). Thus, positive feedback loops are avoided and better control of the analyzer is permitted. A network analyzer, or other signal measuring device (242), logs the waveforms (from which s-parameters derived) observed at ports of the DUT 206, thereby allowing the behavior of the DUT 206 under various load conditions to be analyzed.