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Comparison of thermal coefficients for two microwave detectors
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Mackenzie, Anne I. |
| Copyright Year | 2001 |
| Description | Laboratory measurements were performed to compare the thermal coefficients of two microwave detectors that might be used for direct detection in L-band radiometers. In particular it was desired to compare the performance of a new-technology flash ADC (analog-to-digital converter) against that of an older-technology diode detector in series with a VFC (voltage-to-frequency converter). The outputs of two state-of-the-art detectors were recorded as a constant 1.414-GHz signal was input and the physical temperatures of the detectors were varied over a range of 10 C. As a further experiment, each detector was tested with a noise diode source and with a sine wave synthesizer source. Thermal coefficients were computed in terms of W/C and in terms of ppt/C at nominal operating temperatures reasonable for the individual devices. Finally, thermal coefficients were calculated in K/C to indicate the change in brightness temperature seen by a theoretical sea surface salinity radiometer employing each detector. The K/C for the flash ADC was determined to be about 2.8 times that of the diode/VFC. Different reactions of the ADC to a noise input and a sine wave input indicated that ADC tests for radiometric purposes, such as this one, should be performed using a noise input. |
| File Size | 1168984 |
| Page Count | 22 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20020016711 |
| Archival Resource Key | ark:/13960/t59d1wh8t |
| Language | English |
| Publisher Date | 2001-12-01 |
| Access Restriction | Open |
| Subject Keyword | Electric Potential Ultrahigh Frequencies Frequency Converters Sine Waves Diodes Salinity Microwave Radiometers Radio Frequencies Detectors Brightness Temperature Heat Transfer Coefficients Analog To Digital Converters Operating Temperature Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
