Few words about me:

From very childhood I loved computers, electronics, lasers, sulfuric acid and liquid nitrogen. I always wanted to be making microchips, UAVs and see nuclear explosion.

Now I am doing software engineering and in the spare time - some microelectronics and physics/chemistry experiments.

I live and work in Russia, Moscow.

Solar eclipse 2015

Today there was 65% solar eclipse in Moscow. Probably the last time I am taking astronomy photos with Sony 500mm/F8 - my new telescope is already at the post office
March 20, 2015

AMOLED shenanigans and new microscope lens Olympus LUCPlanFl 20x/0.45

Finally managed to break smart phone glass for the first time. FIrst 4 times it was hitting concrete just fine, and now it landed straight face-down: screen was shattered. Bought glass replacement kit on ebay including UV-curing glue. Old glue+glass is removed by heating to ~120-150 °C.

Unfortunately I managed to overheat 1 spot to 220 °C which lead to unexpected effect: black (organic?) contrast-boosting pigment has burned and revealed display internals in more details. Also, the most sensitive, blue subpixels stopped working in this spot. With my "new" (ebay again) microscope lens LUCPlanFl 20x/0.45 with cover glass thickness correction I managed to make photo of AMOLED internals with more details (for comparison see earlier photos):
March 20, 2015

My precious... ADC

Received few interesting chips from ebay for experiments and decapsulation...
Finally can play with fast ADC (16-bit 10MSPS, 14-bit 190 and 400MSPS), DAC.
It's hard to run ADS5474 at 400MSPS for fun, so it goes straight to acid

But with EPM7128 I made a mistake : I recalled that MAX7000 is the last Altera CPLD with 5V IO. But these specific chips appeared to be 3.3V ones (postfix A-3.3V, B-2.5B. 5V ones has postfix S or none)
 
February 18, 2015

PCB cross section

Ever seen PCB cross section? Total thickness is ~1.5mm, you can even see how glass fibers are interleaved.
 
January 22, 2015

Temperature stability of AirSpy SDR receiver

Recently I got AirSpy SDR-receiver : it has 20Mhz/12bit ADC comparing to 2.4Mhz/8-bit one in RTL2832-based devices. Capture bandwidth is 9Mhz. Also, it uses TCXO with 1.5ppm frequency error spec. In this article I focus on it's frequency error vs temperature. More detailed review of AirSpy will follow in the nearest days...

BTW, for the first time in human history we have blueberry-cooled electronics:


Here are frequency errors. I was measuring 35-th harmonic of FE-5680A rubidium frequency standard generating 2^23 Hz, i.e. ideal frequency should have been 8192*1024*35=293'601'280 Hz.

HardwareQuartz (E4000+RTL2832)AirSpy TCXO
After warm-up293'627'555 Hz +89.49ppm293'601'318 Hz +0.129ppm
Tcase ~0C293'626'824 Hz +87.00ppm293'601'185 Hz -0.324ppm
Tcase ~60С293'628'227 Hz +91.78ppm293'601'386 Hz +0.361ppm
January 4, 2015

I didn't make it to amateur astronomy (this time)

Recently I've bought telescope optical tube assembly - Levenhuk 200mm F4 carbon - there was nothing else in this class left in stock in Moscow, all sold out. But, as one could expect, chances to get decent Chinese F4 parabolic mirror are slim...

December 23, 2014

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