90 likes | 215 Views
This document outlines the advancements made to the EVLA front-end systems for solar mode operation as of April 24, 2006. Key specifications include a maximum solar flare power level of 100,000 SFU and a "normal" Tsys of approximately 25 K. The design accommodates a wide input range, ensuring that there's no compromise in normal observing capabilities. New components such as high-noise amplifiers and RF switches have been incorporated, along with precise calibration requirements for optimal performance. These enhancements will allow for flexibility and future upgrades without major system overhauls.
E N D
EVLA Front-End CDR Solar Mode EVLA Front-End CDR – Solar Mode April 24, 2006
Solar Power Levels • 1 SFU = 104 Jy = 1250 Kelvins at VLA • Max. flare = 100,000 SFU • “Normal” Tsys ~~ 25 K = 0.02 SFU • Max/Normal = 67 dB range. • Receivers & Noise “Cal” must accommodate 67 dB range. EVLA Front-End CDR – Solar Mode April 24, 2006
Generic Receiver(One PolarizationShown) LNA Polarizer Noise Diode EVLA Front-End CDR – Solar Mode April 24, 2006
Generic Receiver(One Polarization Shown) LNA Polarizer Noise Diode EVLA Front-End CDR – Solar Mode April 24, 2006
Generic ReceiverSolar Additions LNA HNA Polarizer Noise Diode EVLA Front-End CDR – Solar Mode April 24, 2006
New Components Required • “High Noise” amplifier (2) • SPDT RF switch (2) • Steppable (vs. fixed) attenuator (1) EVLA Front-End CDR – Solar Mode April 24, 2006
Amplifier Power Out EVLA Front-End CDR – Solar Mode April 24, 2006
Additional Requirements • Requires accurate “cal” values. • Requires phase transfer between modes. EVLA Front-End CDR – Solar Mode April 24, 2006
Conclusions • No compromise of “normal” observing. • Accommodates wide input range. • Few additional components. • Can be added later without major rebuild. EVLA Front-End CDR – Solar Mode April 24, 2006