| ??? 06/12/12 14:07 Modified: 06/12/12 14:09 Read: times |
#187674 - I must have missed a step ... Responding to: ???'s previous message |
Mahmood Elnasser said:
I'm searching for more capable scope to buy. I tried the local shops but prices are huge. I borrowed a 100MHZ Fluke 199C to evaluate and buy but to be honest I'm not spending $2000 for such a crap. Speed was acceptable , scope is very easy to use but overpriced.
I was looking at OWON scope 200MHz bandwidth with 16 channel logic analyzer for half price of fluke, but it is chinese and I'm afraid it will be junk. Since you already have the 200 MHz TEK 475, I don't know why you want yet another 200 MHz instrument. In the PRC, they don't strive to build rubbish for export. They're "buying market share" by producing goods of acceptable quality at very reasonable prices, as a consequence of which they hope people will recognize their ability to produce quality products. The rubbish they export is, generally speaking, produce at the behest of Western business, e.g. Wal-Mart and the like, who want primarily to have the cheapest products, and quality be damned. Even major brands sold here in the U.S. have "special" versions for the price-war stores. The manufacturers won't even honor a warranty for Wal-Mart, because Wal-Mart, just as an example, has contracted to have a lower-quality product boxed and shipped to them with a Wal-Mart warranty, which Wal-Mart happily honors for the first 90 days, say, as in the case of a television set, but which the manufacturer won't even attempt to repair if it fails after the Wal-Mart warranty expires. Those people in the PRC are just as capable as those anywhere else, of building quality products. When APPLE hires them to build something cheap, they know what's wanted, and they build it to order. Like Wal-Mart, APPLE knows that people will buy their product irrespective of the quality. I don't like to buy a used scope, it is ok to spend the money if I get what it says on the box. Have you had bad experience with "experienced" products? Over the past 15 years, I've acquired lots of used equipment for my clients and for others who've sought out my help in selecting, purchasing, and "testing" used equipment. I've had no problems, aside from one bad incident with a Chinese seller who boxed-up and sent what was obviously a defective instrument at the outset. Email me and I'll give you details, and how to prevent that sort of trouble. For the FPGA board I can generate clocks with 90, 180, 270 phase shifts so I guess the minimum time step I can generate reasonably is 1.5 nsec. But the clock jitter is about 900 psec. Do you think it is reasonable to generate 1.5 nsec pulses using 300 MHz fpga or shall I try the circuit proposed by the late Jim Williams in the EDN design ideas Nov 11 2004?
Mahmood I couldn't find the article to which you refer. Perhaps you could provide more detail. I don't know why you're concerned about the extremes of what you can produce with programmable logic. Perhaps you could provide a little more detail about where you want to go with that. RE |
