Thanks Sue. That was a pretty good introduction to Synthetic Aperture Radar (SAR). It's a difficult task to try and cover a technology that had been around for over 50 years in a single presentation. It would be good introduction for new engineers, especially if the language was cleaned up a bit. Someone wrote that the language was nothing worse than normal workplace conversational language. Maybe 20 or 25 year ago, but not any more. It only detracts from the presentation. I have seen many a career go bad because of someone assuming that it's normal. I am sure it will come up at his next review.
I was part of the build, delivery, and maintenance of the first digital SAR processor. This was around 1975. Before that, processing was optical. The processor I worked on had four, 6 foot tall, 19" rack cabinets full of electronics. These were separate from the console. Each cabinet was powered by a 10 Volt/500 Amp power supply. One cabinet was for processing "range" and the other three were for "azimuth" processing. The "azimuth" processor was mostly memory. But this was before high speed, high density static rams were abundant. So the memory consisted of thousands of 1K shift registers.
There were so many integrated circuits in the complete processor that the "Mean Time Between Failure" (MTBF) was calculated to be about 15 minutes. However, the system was very failure tolerant and had a rather unique "Built In Test Equipment" (BITE) capability. This allowed a support person to determine which of the >800 circuit boards was bad. You could even turn off one complete cabinet of "azimuth" memory and still run the processor at half resolution. THE BITE ran all the time so if anything failed during processing you would just hot swap the bad board with a good one and continue processing.
The biggest issue was heat. It took two 5 ton air conditioners, that were ducted directly into the cabinets, to keep the processing cabinets from melting down.
73, Martin, K7MEM
Ash Fork, AZ
In my area, it seems that every pickup truck or SUV comes with one or more dogs. It's so common that I can only assume that the dog(s) must come with the vehicle. So logic tells me that, if you want to keep the truck for a long time, go for the multi-dog option. Otherwise, if the dog dies, you have to buy a new truck. I have five dogs (4 dogs as of 4/4/2013, RIP Katie), so I'm set for a few years.