Show us your square wave - Page 1
Forum section: electronics / testgear

author: Electro Fan
author_rank: Super Contributor
timestamp: January 15, 2015, 09:14:19 pm
content: Just checking to see if any Agilent, Tektronix, Rigol, or other square wave (function) generator users can show us your highest frequency square wave that looks like a strong square wave? Would be especially interested to see the best high frequency square wave from any Rigol DG1032Z and DG1062Z users, but all makes and models welcome. Thanks, EF- kind of curious to see what is the lowest price device is that can produce a really good looking square wave at 1, 5, 10, 20, and 30 MHz?

author: katzohki
author_rank: Frequent Contributor
timestamp: January 15, 2015, 09:36:05 pm
content: Current stuff or older stuff too? I'm picking up a couple older function gens in about a week.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 15, 2015, 09:40:18 pm
content: Quote from: katzohki on January 15, 2015, 09:36:05 pmall examples welcome

author: katzohki
author_rank: Frequent Contributor
timestamp: January 15, 2015, 09:47:53 pm
content: BK 4011A:BNC directly to scope input @ ~5MHz

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 15, 2015, 10:10:20 pm
content: Rigol DG2021A on Hameg HMO20245V Amplitude, 2.5V Offset, 50% DC, High Z and 50Ohm in/out, BNCNote: 25MHz maximum and for some reason selecting 50Ohm limits the amplitude to 2.5V over 10MHz.

author: rob77
author_rank: Super Contributor
timestamp: January 15, 2015, 10:10:51 pm
content: how would you know it's really a perfect square wave without a scope with infinite bandwidth ?

author: tautech
author_rank: Super Contributor
timestamp: January 15, 2015, 10:12:56 pm
content: Quote from: Electro Fan on January 15, 2015, 09:14:19 pmThere are quite a few variables as to how these could be interpreted.It's all very well to ask for sample waveforms, but you will get so many results that aren't worth a knob of goat shit unless you specify how the FG is connected to the scope.50 Ohm coupling ?Hi Z coupling?Probe connection?BNC Cable connection?Most AWG's specify a square wave to only a portion of their max sine wave capabiliy to remain within their risetime specs.This is what you need to see:(Siglent SDS2304 internal AWG 1MHz 50 Ohm source & termination, Coax connection)

author: c4757p
author_rank: Super Contributor
timestamp: January 15, 2015, 10:19:19 pm
content: Quote from: tautech on January 15, 2015, 10:12:56 pmGood point. Nobody should even bother posting here unless they've used a properly terminated connection. Otherwise, you're not seeing the square wave, you're seeing the LC characteristics of the cable.Youmightget a decent signal if you stick a high-bandwidth scope probe right into the BNC output of the function generator, as well, though that's only if the function generator's output amp is rather close to the back side of the jack.

author: katzohki
author_rank: Frequent Contributor
timestamp: January 15, 2015, 10:48:31 pm
content: Proper termination? Oh boy, you really are asking for the moon!

author: jpb
author_rank: Super Contributor
timestamp: January 15, 2015, 10:52:56 pm
content: My scope doesn't like anything above 5Vrms for the 50 ohm input so I've produced two square waves at 4.5Vrms nominal at 20MHz and 30MHzfor an Agilent 33522A. NB the rise time is slow (officially 8.7nsecs) but the curves are smooth.It is interesting to note how inaccurate the peak-to-peak is, it should be 9V for a perfect square. The rms is obviously out as the waves are far from square at these frequencies.The peak-to-peak was much closer down at 1V or less.Note, I've not used averaging but I did have equivalent time sampling turned on and the waveforms are very smooth still because the jitter is very small on the Agilent.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 15, 2015, 11:00:53 pm
content: 100GS?Jesus Christ!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 15, 2015, 11:28:23 pm
content: 100 MHz into 1S1 50 ohm input.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 16, 2015, 01:16:38 am
content: 100GS with "EQU" at the top (I assume indicating equivalent time sampling).It's not a square wave exactly, but it is pushing the instrument BW:350MHz TDS460, coaxial connection, internally terminated. (150MS instrument, so again, the 10GS is "ET".) Ch.2 is a 10x probe (also more-or-less coaxially connected), with a shorter cable hence the time difference.Tim

author: joeqsmith
author_rank: Super Contributor
timestamp: January 16, 2015, 02:31:59 am
content: Quote from: Electro Fan on January 15, 2015, 09:14:19 pmHummm..... Not really sure what you are looking for but I can't let that 1nS rise fall time be the record holder.So, here's my vintage 90's LeCroy DSO looking at one leg from my 70's HP8640B RF generator with an LVDS driver.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: January 16, 2015, 03:09:47 am
content: Tektronix 2101 Generator, Tektronix 7104 & 7A29 & 7B10.Tek 7A29 is 50 ohm input.Gore coax with APC 3.5 connectors and APC-3.5 to BNC adapters between the Tek 2101 & 7A29 input.Maybe I'll dig out the Tektronix Type 106.Bernice

author: joeqsmith
author_rank: Super Contributor
timestamp: January 16, 2015, 03:44:11 am
content: If 370ps was not fast enough.... Vintage HP8660 with PECL buffer.

author: mazurov
author_rank: Frequent Contributor
timestamp: January 16, 2015, 03:55:21 am
content: Tektronix 7000-series with 7S12 plugin. S-52 pulser into S-6 head.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 16, 2015, 04:01:56 am
content: Hi,Here is a Tektronix 11801 scope mainframe using a SD26 sampling head 17.5 ps risetime showing the output pulse from a SD24 TDR head. The combined risetime of the pulse generator and the scope is 26psLight travels 7.8mm in 26ps !!Regards,Jay_Diddy_B

author: pickle9000
author_rank: Super Contributor
timestamp: January 16, 2015, 04:27:31 am
content: I'm kinda liking this thread.

author: LabSpokane
author_rank: Super Contributor
timestamp: January 16, 2015, 05:09:19 am
content: Am I the only one baffled by the question? Are we trying to prove Fourier here? That said, I plan to win the race with my 18000 ps rise time. More is better, right...?Agilent MSOX2024 with the internal function generator.(And thanks for the thread. It finally got me off my ass to get the scope plugged into BenchVue.)

author: Rupunzell
author_rank: Frequent Contributor
timestamp: January 16, 2015, 06:00:41 am
content: I'm waiting for images from the Hypress PSP-1000 or PSP-750.Point of of this race when the initial question was "affordable" square wave generators ?More often than not, web forums discussion become a battle or race to see who can prove they are at the top of their ...Bernice

author: mazurov
author_rank: Frequent Contributor
timestamp: January 16, 2015, 06:04:48 am
content: Define "affordable". My setup can be had for less than $100, At present, I'm looking to buy a rig similar to JDBs and for 50 GHz bw configuration I'm hoping to spend ~$300 shipped.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 16, 2015, 06:21:45 am
content: Quote from: 0xdeadbeef on January 15, 2015, 11:00:53 pmIt's RIS which is a form of Equivalent Time Sampling, not real-time sampling. It's only 2GSa/s (1GSa/s with all channels active) in real-time mode for the WaveJet.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 16, 2015, 06:44:37 am
content: Quote from: Rupunzell on January 16, 2015, 06:00:41 amThe clock generator from a PC can be sawn off the motherboard.