Products > Test Equipment
Show us your square wave
DIPLover:
--- Quote from: DIPLover on January 17, 2015, 05:57:00 am ---10, 20 and 40MHz square waves from Altera Stratix FPGA Enhanced PLL to Tektronix 2465. CMOS 2.5V IO standard.
The old boat anchor is still beating specs (a little) 30 years after being built (and 10 years after last pro calibration sadly :-[ )
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Just received today my Rigol DS2072A, fully unlocked to 300MHz bandwidth. Here are the results of the same measurements with identical setup.
Rise time @ 40MHz is a bit worse than the venerable Tek 2465 but quite respectable. With all the fantastic DSO capabilities, this will be a worthwhile companion to the old clunker I believe.
-jeffB:
--- Quote from: Hugoneus on January 22, 2015, 04:45:18 pm ---Alright, alright... How about an 81Gb/s circuit I made a while back with a rise time of 5.2ps? O0
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Oh, come on. There HAS to be SOMEONE around here doing millimeter-wave work... :)
katzohki:
To get back on topic, here is a comparison between two different function generators, both running at 50kHz. You can clearly see that, yes indeed there is a difference in the shape "quality" between them. Both are 50 ohm terminated.
First a HP 8116A:
You can see that the square wave is a very tight shape and has rise time of 6.3ns.
Next the HP 8904A:
The edges are more rounded and the rise time is ~1.7us.
You can see a good bit of difference between them. The HP 8116A is a 50MHz generator and will, in my opinion, still output a good square wave up into 25MHz or so. The HP 8904A, on the other hand, is rated at 0-600kHz for sine and 0-50kHz for square (and ramp / triangle) so it is working at its absolute upper limit. They both are very nice units and the HP 8904A is particularly versatile, but you can see that each has its application and yes indeed not all FGs are made alike.
PS: I posted a review of the HP 8904A on my blog (shameless plug) in case you might be interested and I'm planning one on the HP 8116A as well. http://katzelectronics.blogspot.com/2015/01/hp-3904a-review.html Just in case you might be interested. :D
PPS: Ignore the 2kV/div on channel one. I normally have a 1000:1 scope probe on that channel and was too lazy to change it. ::)
Teneyes:
I see Rigol DSO displays are being posted on this thread and comments about overshoot.
I wish to inform All the effects of the SinX/X interpolation on the sample data for Rigol DSOs
In the displays below I used My DS2000 to show a Perfect 62.5MHZ square wave Sampled at 2 GSa/s
1st display shows the sample data in Dot Mode , perfect step transistions.
2nd display shows how the Sinx/X process is implemented on the Rigol DS2000, and shows ringing!
Owners need to be aware of this at Faster scan rates, where sample data count is low for the displayed area
a bit OT
Also someone commented that pulses are mainly used for clocking.
in the 3rd display I show how a pulse train can produce a Spread Spectrum of frequencies
for bandwidth testing. The duality of Time and Frequency Domains
tautech:
--- Quote from: Teneyes on January 28, 2015, 12:39:30 am --- I used My DS2000 to show a Perfect 62.5MHZ square wave Sampled at 2 GSa/s
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Source?
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