When I was first in college I rember working at the original IBM PC Store. Most of my work involed working on computers in doctor and legal offices. Typewritters were being replaced and these were the only places which had computers for the most part. Now every one has several.
In some ways bandwidth is the least important parameter. For a 100 MHz clock rate, you need a bandwidth of at least 350 MHz. More important are things like triggering, sampling rate (for digital scopes), pulse capture, etc. It would take at least an hour to explain all of the factors involved. Look here http://www.tek.com/learning/oscilloscope-tutorial for tutorials.
OK -- sorry everyone -- I have to go myself -- more later -- C U Tomorrow -- please pass the word about this course to your friends and co-workers -- also spread the word via Twitter and LinkedIn and suchlike...
There's also DDR ram that stands dor "double data rate" -- the idea here is that instead of just clocking (reading/writing) it on one edge of the clock (like the rising edge) you do so on both edges of the clock...
My first Frequency Counter designed by Hewlet Packard had at least 50 vacuum tubes. Each digit was repsented by a vertical column of neon light bulbs labeled 0 thru 9. I believe it went as high as 10 Mhz.
After it died, I discovered that it had a temperature controlled oven with a 100 Khz Crystal inside for the time-base and also several diiodes used for other purposes. I believe it was one of the first counters made using combined solid state and vacuum tube technology circa 1956 give or take a few years. I purchased it in 1976 at a local school rummage sale for just $5.00
vlad, I don't know if this is the best venue to request free consulting on your engineering problems. This is a basic introductory fundamentals class, right?
(re:We use pig transmitters that emit low frequency signals and a receiver is supposed to accurately track that signal but our receiver catches any undesired low frequency signal which is not necessarily the one from the transmitter. What is the ideal way to get rid of this problem?)
DRAM is like SRAM in that it's volatile (it forgets things when power is removed from the system). That's when we move to Flash. Flash memory is non-volatile -- it remembers its contents when power is removed from the system. So in your computer we use Flash to store the bottom-level boot code -- ebnough to get th ecomputer started so that it can read the next level of th eoperating system off a hard disk drive.
So in a computer system SRAM is used for the on-chip cache memory and anywhere else you need the highest speed, while DRAM is used to provide the bulk storage -- when you see a computer tha tboasts "4GB of RAM" -- it's DRAM theyu are talking about...
DRAM syands for Dynamic RAM -- in thsi case each cell is formed from a capacitor and a transistor (the capacitor is formed using transistor level processes -- even better tha tcapacitir is formed on top of the transistor (or vice versa -- I can;t remember). The advantage of DRAM is that it's very dense (close-packed) you gan get a lot of it in a chip. Also it is low on power consumption. The disadvantage is that it's slower than SRAM
about packaging - I remember the first time I saw surface-mounted chips. seemed so obvious (in retrospect, of course) - I used to take broken DIPs, put them on the table and push down so the legs would bend underneath. wish I'd've thought of soldering them that way...
SRAM stands for static RAM -- the name is historical -- a single SRAM cell stores 1 bit of information (a 0 or a 1). The cell is formed from 4 to 6 transistors. SRAM is volatile -- when you power the system off it forgets what it was storing. SRAM is very fast but it consumes a lot of power and the 4 to 6 transistors occupy a lot of silicon real-estate (relatively speaking)
the transmitter emits electromagnetic pulses of freq 15 to 30 Hz which the receiver is supposed to track above ground but due to random movements of the receiver antenna the unit falsely thinks it detects 15 to 30 hz signal but its actually not from the transmitter?
I got here late... Did you address the relationship between the sampling rate, the number of bits per sample and the coeffients of the Fourier series for the waveform one is converting from analog to digital? JUST KIDDING! I'm really writing to express my disappointment having missed bagpipe joke.
...and to suggest that maybe these presentatins have TWO posting areas side by side. One for everyone who wants to discuss their audio quality, and another one to discuss the ACTUAL PRESENTATION. Is that possible?
In many cases a MCU doesn;t use external memory -- like if you have a low-power wireless network, the MCU powers up running th eprohram in its-on-chip Flash memory -- this sort of MCU is also found in microwave ovens, toasters, washing machines, dish washers, and so forth
@vlad, I did some work in the past with VLF 20-200Hz. The trick was to reject all in-band interference such as power line 60, 120, 180 hz. motion of the detector also induced low frequency signals, so a low frwquency negative feedback to restore the base line of the signal is also neeed.
MCU stands for microcontroller unit -- this is essentially a microprocessor coupled with outher stuff like on-chip Flash memory, on-chip SRAM, counter timers, DMA, communications interfaces like UARTS, a few analog inputs feeding into A-to-D converters -- all mounted on the same die and presented in a single package
how to track the low frequency signal(15 to 30 Hz) from beneath the ground surface accurately?
We use pig transmitters that emit low frequency signals and a receiver is supposed to accurately track that signal but our receiver catches any undesired low frequency signal which is not necessarily the one from the transmitter. What is the ideal way to get rid of this problem?
MPU stands for microprocessor. Generally speaking this will be a central processing unit (CPU) with a few additional functional blocks like on-chip mcache memory, a floating point co-processor, and so forth...
thanks, Max! later slides were Amazingly Interesting! especially silicon interposer - looks like a teeny-tiny 2-sided circuit board (vias and all...) made of silicon and stuck into the IC. what's old is new again.... :)
The chips that got hot were the 64k memory chips circa 1980, had to pretest all of the chips to weed out the slow ones and then try to match compatable parts to even get it to work. Life is alot easier now thought maybe more confusing but can't wait to see what comes next.
@Kentj: that sounds like your company or ISP is blocking blogtalkradio or some other essential resource needed to bring the audio to you. Consider listening to the archived audio elsewhere (like at home) and see how that works. I can listen at home but the class happens while I am at work and my company blocks the audio so I typically listen on a smart phone.
@richnass: I do have a similar audio problem but on a much smaller and less annoying scale than justheretolearn does. I am listening on a smart phone so I assume that local congestion or temporary signal loss as I move around accounts for the occasional drops.
Via and Blind Via -- go to the http://www.element14.com/community/index.jspa (Element 14 web site) get a copy of Eagle -- watch the tutorial and get all that stuff explained. It's a hangout for high end hobbyists and wannabe engineers like me.
DaveWR - it comes out looking like a lumpy cylinder. Forget how many lumps, but U are right - less stress points, and it certainly makes it easier to handle a round wafer. Lumpy, irregular wafers don't work too well in automated equipment
Why are the crystals round? (Cylindrical?) WHy not?
A geologist might say that rocks with corners are "high energy" subject to the corners breaking off and cracking. I suspect it's the same issue -- also a way of making a low stress chip. AIrliners have round windows to reduce stress... Just guessin' but maybe it's the answer.
The first transistor I had or used was a Raytheon germanium PNP, the CK722, in a beautiful blue case, that I purchased for $0.99. I still have it and it was still functional the last time I checked (but that was many years ago now).
I still have a Staedler Mars slide rule, some vac tubes and a box full of 2N2222 transistors -- guilty as charged. But I did originally work on VLSI when I started my career... (Probably before Max. ;-) )
@jjrochow: "Max did not address the relationship between the sampling rate, the number of bits per sample and the coeffients of the Fourier series for the waveform one is converting from analog to digital."
New versions of BASF's Ecovio line are both compostable and designed for either injection molding or thermoforming. These combinations are becoming more common for the single-use bioplastics used in food service and food packaging applications, but are still not widely available.
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