Author Topic: Show us your square wave (Read 206537 times)

Electro Fan · « **on:** January 15, 2015, 09:14:19 pm »

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?

katzohki · « **Reply #1 on:** January 15, 2015, 09:36:05 pm »

Current stuff or older stuff too? I'm picking up a couple older function gens in about a week.

Electro Fan · « **Reply #2 on:** January 15, 2015, 09:40:18 pm »

Quote from: katzohki on January 15, 2015, 09:36:05 pm

Current stuff or older stuff too? I'm picking up a couple older function gens in about a week.

all examples welcome

katzohki · « **Reply #3 on:** January 15, 2015, 09:47:53 pm »

BK 4011A:

BNC directly to scope input @ ~5MHz

0xdeadbeef · « **Reply #4 on:** January 15, 2015, 10:10:20 pm »

Rigol DG2021A on Hameg HMO2024
5V Amplitude, 2.5V Offset, 50% DC, High Z and 50Ohm in/out, BNC
Note: 25MHz maximum and for some reason selecting 50Ohm limits the amplitude to 2.5V over 10MHz.

rob77 · « **Reply #5 on:** January 15, 2015, 10:10:51 pm »

how would you know it's really a perfect square wave without a scope with infinite bandwidth ?

tautech · « **Reply #6 on:** January 15, 2015, 10:12:56 pm »

Quote from: Electro Fan on January 15, 2015, 09:14:19 pm

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?

There 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)

c4757p · « **Reply #7 on:** January 15, 2015, 10:19:19 pm »

Quote from: tautech on January 15, 2015, 10:12:56 pm

50 Ohm coupling ?

Good 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.

You might get 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.

katzohki · « **Reply #8 on:** January 15, 2015, 10:48:31 pm »

Proper termination? Oh boy, you really are asking for the moon!

jpb · « **Reply #9 on:** January 15, 2015, 10:52:56 pm »

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 30MHz
for 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.

0xdeadbeef · « **Reply #10 on:** January 15, 2015, 11:00:53 pm »

100GS?

Jesus Christ!

Alex Eisenhut · « **Reply #11 on:** January 15, 2015, 11:28:23 pm »

100 MHz into 1S1 50 ohm input.

T3sl4co1l · « **Reply #12 on:** January 16, 2015, 01:16:38 am »

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

joeqsmith · « **Reply #13 on:** January 16, 2015, 02:31:59 am »

Quote from: Electro Fan on January 15, 2015, 09:14:19 pm

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?

Hummm..... 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.

Rupunzell · « **Reply #14 on:** January 16, 2015, 03:09:47 am »

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

joeqsmith · « **Reply #15 on:** January 16, 2015, 03:44:11 am »

If 370ps was not fast enough.... Vintage HP8660 with PECL buffer.

mazurov · « **Reply #16 on:** January 16, 2015, 03:55:21 am »

Tektronix 7000-series with 7S12 plugin. S-52 pulser into S-6 head.

Jay_Diddy_B · « **Reply #17 on:** January 16, 2015, 04:01:56 am »

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 26ps

Light travels 7.8mm in 26ps !!

Regards,

Jay_Diddy_B

marshallh · « **Reply #18 on:** January 16, 2015, 04:22:44 am »

pickle9000 · « **Reply #19 on:** January 16, 2015, 04:27:31 am »

I'm kinda liking this thread.

LabSpokane · « **Reply #20 on:** January 16, 2015, 05:09:19 am »

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.

)

Rupunzell · « **Reply #21 on:** January 16, 2015, 06:00:41 am »

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

mazurov · « **Reply #22 on:** January 16, 2015, 06:04:48 am »

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.

Wuerstchenhund · « **Reply #23 on:** January 16, 2015, 06:21:45 am »

Quote from: 0xdeadbeef on January 15, 2015, 11:00:53 pm

100GS? Jesus Christ!

It'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.

Alex Eisenhut · « **Reply #24 on:** January 16, 2015, 06:44:37 am »

Quote from: Rupunzell on January 16, 2015, 06:00:41 am

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 ?

The clock generator from a PC can be sawn off the motherboard.


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Author Topic: Show us your square wave (Read 206537 times)

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