[time-nuts] Question concerning failure and value of HP 5371A
Hal Murray
hmurray at suespammers.org
Sat Oct 15 15:38:56 EDT 2005
> The point is, I do not find gates capable to work well beyond 30, 40
> MHz. I there somebody having a helpful idea how this could be solved?
How fast do you want to go? Modern FPGAs are loafing at 100 MHz.
A major problem at high speeds is signal integrity. You can't toss something
together with proto-board technology. You need a good ground plane and power
supply decoupling. (and they generally require several power supplies)
If you want to get started with FPGAs, the Spartan-3 starter kit at $100 is a
pretty good package. You can get it from Xilinx or Digilent
http://www.digilentinc.com/info/S3BOARD.cfm
It's got a 50 MHz osc. (Beware, the connectors around the edge don't have
enough ground pins for serious high speed work.)
Peter Alfke, chief apps wizard at Xilinx, has made a hobby out of using FPGAs
for things like measuring pulse duration and/or frequency. He's posted
several neat ideas on comp.arc.fpga over the years. They may be hard to find
- "counter" is a popular term.
The latest trick that I remember is to use the high-speed SERDES logic on
newer chips to sample a raw signal. You get 20 bits in parallel with a
sample rate of 2 GHz. Then slower logic can count the transitions or
whatever.
Message-ID: <BC8772E1.5C19%peter at xilinx.com>
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