Cascade Microtech, Inc.

Bernard W Leake

Eric W Strid

Andrew C Davidson

A one port tuner having a source port for connection to a device under test so that, in combination with a noise meter, the noise performance of such device can be evaluated. Preferably the one port tuner includes a plurality of predetermined admittances, a switching device having an output port for selectively connecting one of the admittances to the output port, and a two port device having a selectable response and interconnected between the output port of the switching device and the source port of the one port tuner. Desirably, the two port device includes a multiple-state attenuator where the signal passing through the attenuator is selectable in degree. Alternatively, or in combination, the two port device includes a phase shifter where the phase of the signals passing through the phase shifter are selectively shiftable. Optionally, the one port tuner includes a variable amplifier, variable phase shifter, and variable bandpass filter in serial connection with each other where the two legs of the serial connection are coupled to the source port by a signal feedthrough device.

Noise parameter test apparatus

Method and apparatus for simultaneously measuring noise power of a two-port device under test (DUT) using a one-port tuner, a low-noise amplifier, a power divider with a plurality of outputs, and a plurality of noise meters. The noise meters are configured to measure available noise power in different frequency ranges which are closely spaced around a selected central frequency, thereby yielding the noise parameters of the DUT at the central frequency.

Noise parameter test method and apparatus

A method of measuring and compensating for measurement frequency inaccuracies encountered when measuring noise power of a device under test within a desired calibrating frequency range. The method includes sweeping a frequency synthesizer through a frequency range which includes the desired measurement frequency range. Power is measured for different synthesizer frequencies with the noise power meter set to the desired frequency range. Alternatively, the frequency synthesizer may be set to the desired measurement frequency and the noise power meter swept through a range including the desired measurement frequency. The resulting power measurements show the frequency range within which the noise power meter actually measured power. The difference between the desired measurement frequency range and the actual measurement frequency range is the measurement frequency error which may be corrected using a frequency conversion stage to displace test signals by the amount of the measurement frequency error before they are sent to the noise power meter.

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Beaverton, OR, United States of America

Bernard W Leake