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Noise Calibration Systems
Available from Maury Microwave
Description
Maury noise calibration systems (NCSs) are self-contained, highly accurate sources of RF and microwave noise power. These systems are used wherever noise source accuracy is critical. Examples are: receiver noise measurements such as noise figure and effective input noise temperature; calibration of solid state noise sources; evaluation and verification of earth station receivers; and as radiometer reference sources.
Each NCS consists of two (one hot and one cold) or three (one hot, one ambient and one cold) thermal noise sources whose outputs can be easily switched into a common calibrated output port. This arrangement provides a unique combination of accuracy and convenience. The output switch makes operation of the NCS in a noise performance measurement as simple as using a solid state noise generator - without the accuracy penalty associated with the latter. The plot below illustrates the accuracy improvement gained by use of an NCS in typical measurement applications (effective input noise temperature).
The cold noise source is a liquid nitrogen (LN2) cooled termination similar to Maury's cryogenic noise terminations. A liquid nitrogen level sensor and an automatic fill system maintain the proper nitrogen level. (The user must provide a suitable liquid nitrogen reservoir.) The cold termination is also pressurized with helium at 2 psi. Pressure is maintained by a regulator that requires 20 psi maximum from an external user-supplied source. Since helium bottles are usually pressurized to about 1,000 psi or more, Maury's MT152A pressurizing system is recommended as an accessory.
The hot noise source is a heated termination similar to Maury's hot thermal noise terminations whose temperature is maintained by proportional control to better than ±0.2K by the MT155J controller. Actual temperature is indicated by a digital readout on the controller front panel.
The NCS consists of three assemblies:
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A component mounting plate which holds the cryogenic and heated termination assemblies, the hot/cold or hot/ambient/cold remotely controlled relay(s) and output assembly, and the helium pressure regulator. The LN2 level sensor and fill solenoid are mounted on the cover of the dewar flask. |
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The MT155J controller which contains the temperature control circuitry and a digital temperature readout for the thermal termination, the automatic or manual LN2 fill control circuitry, and the remote noise temperature output switch. |
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The MT155K connects the controller to the mounting plate. |
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Maury Noise Calibration System (MT7098B). |
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Product Data Sheets
(click the links below to download PDF*
copies):
4E-008 ( 49 KB) Technical Data - Model MT7098B - Noise Calibration System
5C-028 ( 2.3 MB) Application Note - Applications of the Maury Noise Calibration Systems; Accuracy & Convenience in Noise Measurement
5C-042 ( 84 KB) Application Note - Theory of Noise Measurement
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