Hi Sean, Useful info, thanks. I was planning on using this to look at LCD pixel clocks 24 - 80MHz, and HDMI pixel clocks (differential, not sure rate). You are right, this device is overkill. \J On Sun, Apr 3, 2011 at 9:35 AM, Sean Breheny wrote: > Hi Jim, > > I am not familiar with the CNT-90, but it looks very roughly similar > to the Agilent 53131A or 53132A Universal Frequency Counters. In fact, > the CNT-90 looks a bit more advanced than the two Agilent units. The > 53131 and 53132 seem to go for about $900 to $2000 on eBay with > Buy-it-Now. In the case of the CNT-90, there are some options which > probably make it much more valuable, such as the ultra-high-stability > timebase and the higher frequency input ability (GHz). So, $1000 > sounds like a reasonable price for a guaranteed-working CNT-90. I'm > not sure about a totally as-is one, although if you can inspect it > first hand and try it out, perhaps. > > Basically, it looks to me like the CNT-90 is a device for studying the > statistics of a clock signal, such as jitter, absolute frequency, > Allan variance, and histogram of individual cycle period. It sounds > like it would be useful to a cal lab or a time nut (someone who likes > to try to build ultra high stability clocks), and maybe also to some > RF experimenters who need low phase-noise RF sources or clocks for > spread-spectrum applications. It does NOT sound to me like the best > way for an electronics hobbyist to drop $1000 unless he already has > lots of other more generally-useful equipment like a nice digital > scope. > > What kind of LCD clocks would you be debugging? I do not think the > CNT-90 would be very useful for most general debugging of simple > clocks - a scope and some good basic skills and tricks can easily do > such work without something as high-end as the CNT-90. > > I do not really see what it has to do with HDMI at all, although I > admit that I am not very familiar with HDMI. > > Sean > > > On Sat, Apr 2, 2011 at 9:10 PM, james tornes wro= te: >> Hi, >> >> I've happened upon a Spectracom CNT-90 at a yard sale. The seller >> wanted a grand for it. >> >> http://www.spectracomcorp.com/ProductsServices/TestandMeasurement/Freque= ncyAnalyzersCounters/CNT90TimerCounterAnalyzer/tabid/1280/Default.aspx >> >> Anyone know what the going price for a used CNT-90 should be? I >> couldn't find any on ebay or the usual trade sites. While we're on the >> topic, is this kind of device going to be useful for debugging stuff >> like LCD clocks or HDMI? >> >> \Jim >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .