Anritsu Company

David Rangel

Jon Martens

Peter A Kapetanic

An instrument is provided for measuring a noise figure with significant flexibility. The instrument includes a noise source ( ) and a vector network analyzer (VNA) ( ). The VNA ( ) includes an external connector port ( ) for removable connection of the noise source ( ). The noise source ( ) can be connected to the VNA backplane port ( ), or directly to a DUT ( ). The DUT ( ) can be connected to both VNA test ports ( ) if the noise source ( ) is connected to port ( ), or only to test port ( ) if the noise source ( ) is directly connected to the DUT. A receiver connected to the test port ( ) includes a downconverter ( ) providing an IF signal through either a narrowband IF channel ( ) or a wideband IF channel ( ) for providing both wideband and narrowband power measurements enabling fast accurate measurement of a noise figure.

Flexible noise figure measurement apparatus

A vector network analyzer (VNA) is provided with three test ports and an integration of hardware and software to make an integrated set of measurements for two and three port devices. The integrated capability allows for fast, versatile measurements that benefits, in accuracy and convenience, from sharing of data and resources with other measurements. The VNA includes a first signal source which is selectively connectable through reflectometers to two of the three VNA test ports. A second signal source provides connection through a third reflectometer to a third test port to enable full vector error corrected 3-port S-parameters measurements to be made. The two signal sources, along with software configuration of the VNA to operate in a non-ratioed mode provides for measuring second and third order intercept measurements. The two signal sources and software also enable the VNA to be used to make frequency translation measurements of a mixer including accurate frequency translation group delay measurements. The VNA further includes components to enable DUT noise figure to be determined, and to provide automatic calibration. The VNA further provides a process for harmonic measurement accuracy enhancement, and includes a dual mode multiple source/LO module to provide common mode noise rejection and fast measurement speed.

Vector network measurement system

A method is provided for eliminating the source harmonic component from VNA measurements of the output of a device under test (DUT). A standard vector measurement, GHx, is first measured from the DUT using the VNA. The value GHx is composed of two elements, the DUT's harmonic response to a fundamental input from the source, and the DUT's linear response to the harmonic input from the source. The harmonics from the source which are linearly passed by the DUT, GNx, are then measured with the VNA. The output harmonic generated by the DUT, Hx, is then calculated using vector subtraction according to the equation Hx&equals;GHx&minus;GNx. The output harmonic Hx will then be free from source harmonic components.

Process for measuring output harmonic relative to output fundamental with enhanced accuracy

A method for determining the harmonic response of a device under test (DUT) to the input fundamental frequency component of an input signal is performed on a vector network analyzer. A first response of the DUT at the harmonic frequency is obtained by measuring the linear response of the device at the harmonic frequency of interest after appropriate normalization. A second response of the DUT is obtained by measuring the response of the DUT at the harmonic frequency to an input which comprises a source input fundamental with its harmonic components after appropriate normalization. The harmonic response of the DUT to the source input fundamental alone is computed from the first and second responses. Such computations allow the harmonic response of the DUT to be measured free of stimulus source harmonics, so that overall harmonic measurement accuracy and dynamic range is enhanced.

Process for harmonic measurement accuracy enhancement

A method for determining the harmonic phase response &ang;POx of a device under test (DUT) is performed on a vector network analyzer (VNA). The phase &ang;GN,of the transfer response GN,of the DUT at the fundamental frequency is determined from VNA measurements after appropriate normalization. The corrected phase &ang;GHxC of the harmonic transfer response of the DUT is determined from VNA measurements after appropriate normalization. The corrected phase &ang;GHxC of the harmonic transfer coefficient GHx is subtracted from a predetermined phase reference &ang;refx to obtain a difference &ang;refx&minus;&ang;GHxC, and the phase &ang;GN,of the transfer coefficient GN,at the fundamental frequency is added to the difference &ang;refx&minus;&ang;GHxC to obtain the harmonic phase offset &ang;POx. For the second and third harmonics using a clipping waveform, the phase reference &ang;refx is 180&deg;.

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San Jose, CA, United States of America

David Rangel