Introduction
Noise occurs naturally in any active device or
circuit, and limits the minimum levels of useful signals. With a cell
phone, for example, it can interfere with a weak signal, and interrupt a
call. Therefore, it is important to design circuits to minimize the
effects of noise. To do this, the noise must be quantified and measured
in the form of noise parameters, comprised of Fmin, Gamma,opt (mag and
phase), and Rn. Note, Noise Figure is a commonly referenced parameter
when discussing LNAs, and most often refers to the 50ohm noise
contribution of a device.
Ultra-Fast Noise Parameters
A new ultra-fast noise parameter measurement method
is able to improve overall calibration and measurement time by a factor
of 100X-400X, bringing measurements that could once take tens or
hundreds of hours to tens of minutes. The new method has two key
features that contribute to the breakthrough speed improvement: 1) The
tuner is characterized with one set of states (physical tuner positions)
that are selected to give a reasonable impedance spread over the
frequency band of interest; and 2) the noise power measurement is swept
over the frequency range at each state, so that the tuner only moves to
each position once. This takes advantage of the fast sweep capability of
modern instruments, as well as saving time by minimizing tuner
movement.
The new noise parameter measurement method provides two orders of magnitude speed improvement. It also produces data that is smoother and has less scatter than the traditional method. The fast measurement speed eliminates temperature drift, and using a VNA with an internal noise receiver simplifies the setup and makes it much more stable and consistent. The much higher speed makes it practical to always do a full in-situ calibration to minimize errors, and to measure more frequencies to get a better view of scatter and cyclical errors, and to be able to use smoothing with more confidence. The higher frequency density also enhances accuracy by reducing shifts due to aliasing.
The 50ohm Noise Figure of a device can be directly measured using the Noise Parameter system, or extrapolated from the Noise Figure contours. Direct measurement is achieved by using an impedance tuner to present exactly 50ohm to the DUT and measuring the associated noise figure (note, the tuner can correct for the non-50ohm system impedance normally presented without a tuner). Noise Figure extrapolation is a standard function within a noise parameter measurement system and uses mathematically determined contours to calculate the expected Noise Figure contribution at 50ohm.
Measured noise parameter data with 73 frequencies using the new method, no smoothing applied, showing Fmin (red), rn (blue), and Associated Gain (purple).
Typical 8-50 GHz single-sweep measurement using a Maury MT7553B01 Noise Receiver Module and a Maury MT984AU01 Automated Tuner with Agilent's PNA-X.
The new noise parameter measurement method provides two orders of magnitude speed improvement. It also produces data that is smoother and has less scatter than the traditional method. The fast measurement speed eliminates temperature drift, and using a VNA with an internal noise receiver simplifies the setup and makes it much more stable and consistent. The much higher speed makes it practical to always do a full in-situ calibration to minimize errors, and to measure more frequencies to get a better view of scatter and cyclical errors, and to be able to use smoothing with more confidence. The higher frequency density also enhances accuracy by reducing shifts due to aliasing.
The 50ohm Noise Figure of a device can be directly measured using the Noise Parameter system, or extrapolated from the Noise Figure contours. Direct measurement is achieved by using an impedance tuner to present exactly 50ohm to the DUT and measuring the associated noise figure (note, the tuner can correct for the non-50ohm system impedance normally presented without a tuner). Noise Figure extrapolation is a standard function within a noise parameter measurement system and uses mathematically determined contours to calculate the expected Noise Figure contribution at 50ohm.
Measured noise parameter data with 73 frequencies using the new method, no smoothing applied, showing Fmin (red), rn (blue), and Associated Gain (purple).
Typical 8-50 GHz single-sweep measurement using a Maury MT7553B01 Noise Receiver Module and a Maury MT984AU01 Automated Tuner with Agilent's PNA-X.
Typical setup for 0.8-18 GHz noise parameter measurements using a Maury MT982BU01 Automated Tuner with the Agilent PNA-X Network Analyzer.
Typical setup for 8-50 GHz noise parameter measurements using a Maury MT7553B01 Noise Receiver Module and a Maury MT984AU01 Automated Tuner with the Agilent PNA-X Network Analyzer.
Application Notes and Data Sheets
• 5A-042 
A New Noise Parameter Measurement Method Results in More than 100x Speed Improvement and Enhanced Measurement Accuracy
• 5C-084 Setting Up ultra-Fast Noise parameters Using the Agilent PNA-X
• 5C-085 Using an Impedance Tuner and Noise Receiver Module to Extend the Agilent PNA-X to 50 GHz Noise Parameters
• Maury Application Notes Library Maury Software and System Application Notes.
PDF (Portable Document Format) files can be viewed with Adobe® Acrobat Reader™.
Download the PDF reader from Adobe.com +
Request printed versions of Maury Product Data Sheets and Application Notes.
A New Noise Parameter Measurement Method Results in More than 100x Speed Improvement and Enhanced Measurement Accuracy• 5C-084 Setting Up ultra-Fast Noise parameters Using the Agilent PNA-X
• 5C-085
Using an Impedance Tuner and Noise Receiver Module to Extend the Agilent PNA-X to 50 GHz Noise Parameters• Maury Application Notes Library
Maury Software and System Application Notes.PDF (Portable Document Format) files can be viewed with Adobe® Acrobat Reader™.
Download the PDF reader from Adobe.com +
Request printed versions of Maury Product Data Sheets and Application Notes.
No comments:
Post a Comment