Saturday, June 03, 2006

First Light!

As if I didn't already need a reason to be crowned "high-priest1 of nerd-dom", here I go again. This time, they're a pair of graphs that almost nobody in the world would care for.

Whatiteez? They're the receiver calibration curves for the new digital receivers I designed for CSU-CHILL :-) They saw first light (well, first microwave, anyway) today. The first order of the day for a radar receiver is a noise cal, and that's just what I did. It's not terribly impressive by radar standards, but -113 dBm minimum detectable signal is still pretty good. To put that into perspective, -113 dBm is 5.01 femtowatts of incident RF at the low-noise amplifier inputs. To put it into further perspective, the radar transmitter generates approximately 600 kilowatts (+88 dBm) of power during it's transmit pulse. The dynamic range here is an astounding 201 dB! Human hearing, by comparison, has a dynamic range of about 150 dB before you go deaf, that's still 105 times less than the power levels CHILL deals with. Considering this radar is rather run-of-the-mill by military standards, I wonder what sort of numbers they deal with.

Note that I ran out of power on my signal generator at the upper end, so the slight compression is due to the signal generator, not the receiver.

In other news, my laptop acted up a couple of days back. Quite funny, I took it out to the radar, plugged in the serial port to a test point on the radar, opened a terminal emulator. Punched keys, nothing happened. Then, quite mysteriously, the laptop powered off. "Strange", I thought, and pushed the power button. The LEDs all blinked and went off again. I thought it must be a dead battery, but as I was plugging in the charger, I noticed a burning smell! WHOOPS! Anyhow, after a while it started working again, so I'm still happy. Back up yer data, folks!

[1] I actually took some "test your nerdiness" quizzes. Most of them put me in the 95th percentile. Ugh, I need a life...

2 comments:

HeShoots_AndScores said...

Hey Jim.
Why're you worried abt the 'nerd' quizzes? Embrace geekdom. It's good for the soul!
Cheers!

Jim said...

Harish,
I'm not worried about being nerdy per se, but > 95th percentile is a hard pill to swallow!