Author Topic: waveform generator advice  (Read 4365 times)

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Offline GregDunn

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Re: waveform generator advice
« Reply #25 on: May 26, 2018, 11:42:41 pm »
Well, VMWare is either $80 or $160 by itself.  Add the $250 for the SAG1021 and PC-only software (required), and we're nearing (or over) $400 already - plus it ties up my laptop while using it.  I could buy a nice simple standalone AWG for a lot less and not have to futz around with a laptop, cables and dongle.  It's just more effort for something that adds features I don't need.  I was hoping there might be a decent no-frills signal generator for considerably less money...  Maybe one of the low-end Siglent models isn't so expensive given the alternatives.

The SAG1021 is an option for the SDS1004X-E DSO series and cannot be operated standalone. I'm not aware of any software for a PC that could replace the scope for operating the AWG.

I know that, but when I looked at the product page on (e.g.) Saelig's site:

https://www.saelig.com/product/sag1021.htm

"SDS1000XEFG Required Software Add $109.00"  That's right under the listed price of $159.

"This product requires Siglent SDS1000X-E-FG software for operation."

So maybe I'm not reading it properly, but it says to me that I need the module AND the software to use it with a scope?

Also, WRT the VMWare software: it's pretty difficult to figure out from the VMWare site but as far as I can tell there is no VMWare Player for Mac.  That product exists only for Windows and Linux, and to run VMWare on a Mac you still have to purchase VMWare Fusion which is at least $80.  For some purposes this combo would be a good deal, but I'm still thinking it's overkill for my intended use.

I agree that one of the standalone AWGs is looking like my best choice.

Now, a question about those: (sorry for the bold, didn't want this to get lost in the reply)  Which AWGs provide a sweep signal output so that you can synchronize the sweep with an external oscilloscope?  Is this a standard feature on the better AWGs?  It's not prominently mentioned on most of the product descriptions.
 

Online nctnico

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Re: waveform generator advice
« Reply #26 on: May 26, 2018, 11:51:37 pm »
Again: a trigger output is pretty standard. AFAIK even the low-end Feeltech generators have this. If your scope can trigger on the width of a pulse (pretty standard) then it can also trigger on the start of a sweep.
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Offline David Hess

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Re: waveform generator advice
« Reply #27 on: May 27, 2018, 02:13:38 am »
Now, a question about those: (sorry for the bold, didn't want this to get lost in the reply)  Which AWGs provide a sweep signal output so that you can synchronize the sweep with an external oscilloscope?  Is this a standard feature on the better AWGs?  It's not prominently mentioned on most of the product descriptions.

A trigger output looks like a standard feature now.  The last time I looked into it, external triggering was only available on the highest end models.

A ramp output can also work with the oscilloscope in X-Y mode (1) but I prefer triggering and Y-T mode because then gated or windowed measurements can be used to make frequency and amplitude measurements at any point of the displayed transfer function.  This is the same capability that markers would provide.

(1) Some old analog sweep generators include a z-axis or blanking output making a ramp and X-Y mode very nice.
 

Offline GregDunn

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Re: waveform generator advice
« Reply #28 on: May 27, 2018, 05:00:54 am »
Again: a trigger output is pretty standard. AFAIK even the low-end Feeltech generators have this. If your scope can trigger on the width of a pulse (pretty standard) then it can also trigger on the start of a sweep.

Agreed; however, I had thought I read in one of the other threads that the low end Feeltech AWGs didn't provide a sweep trigger - at least not without some workarounds.  If that's been fixed, then great.  Not that I'm expecting to buy one but it does mean that pretty much any AWG will work for me.
 

Offline RoGeorge

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Re: waveform generator advice
« Reply #29 on: May 27, 2018, 05:09:24 am »
Which AWGs provide a sweep signal output so that you can synchronize the sweep with an external oscilloscope?  Is this a standard feature on the better AWGs?  It's not prominently mentioned on most of the product descriptions.

My Rigol DG4102 have a similar feature. It's not exactly an analog output with the sweep signal, but a digital output to trigger other instruments.

On the front panel, there are 2 BNC outputs for each channel. One BNC is to output the generated signal, and the other BNC is a TTL level output called 'Sync'. The 'Sync' output can be set to generate an edge at the beginning/middle/some ratio of the sweeping ramp. Page 173/238 http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-0167/0/-/-/-/-/file.pdf
Quote
Sync
DG4000 could output the sync signals of basic waveforms (except Noise), arbitrary waveforms (except DC), Harmonics, Sweep signal, Burst signal and modulated signal from a single channel or two channels at the same time. The sync signal is output from the [Sync] connector at the front panel.
1. Sync On/Off
Enable or disable sync signal at the [Sync] connector. Press Utility  CH1Set  Sync to select "On" or "Off" for the sync signal output. The default is "On", namely transmitting the sync signal to the [Sync] connector. If sync signal is disabled, the output level at the [Sync] connector is logic low.
2. Sync Signals of Various Waveforms
 For Sine, Square, Ramp and Pulse, the sync signal is a Square with 50% duty cycle. It is TTL high level relative to 0V (or DC offset) when the output is positive and TTL low level relative to 0V (or DC offset) when the output is negative.
 For arbitrary waveform, the sync signal is a square with variable duty cycle. The sync signal is TTL high level when the amplitude of the output waveform reaches certain value.
 For harmonics, sync signal is a square with variable duty cycle and takes the harmonic order as reference.
 For AM, FM, PM and PWM, in internal modulation mode, the sync signal is a Square with 50% duty cycle and takes modulating frequency as reference. It is TTL high level in the first half period of the modulation waveform. In external modulation mode, there is no sync signal output.
 For ASK, FSK, PSK, BPSK, QPSK, 3FSK and 4FSK, the sync signal takes ASK/FSK/PSK/BPSK/QPSK/3FSK/4FSK Rate as reference and is a Square
RIGOL Chapter 10 Utility Functions and System Settings
10-4 DG4000 User's Guide
with 50% duty cycle. For ASK, FSK and PSK, in external modulation mode, there is no sync signal output.
 For OSK, the sync signal is a square with 50% duty cycle and takes OSK rate as reference. The sync signal is TTL high level when the internal crystal oscillator starts to oscillate. In external modulation mode, there is no sync signal output.
For Sweep, when "Mark" is disabled, the sync signal is a Square with 50% duty cycle. It is TTL high level at the start of the sweep and changes to TTL low level at mid-point of the Sweep and its frequency corresponds to the specified sweep time, return time, start hold and end hold times. When "Mark" is enabled, the sync signal is TTL high level when sweep starts and transforms to TTL low level at the marked frequency point.
 For a N cycle burst, the sync signal is TTL high level when burst starts and transforms to TTL low level while the specified number of cycles end (if the waveform has a relative start phase, the crossing point may not be zero). For an infinite burst, its sync signal is the same as the sync signal of a continuous waveform.
 For an external Gated burst, its sync signal follows its gated signal. Note that the sync signal will not transform to TTL low level until the last period is finished (if the waveform has a relative start phase, the crossing point may not be zero).
« Last Edit: May 27, 2018, 05:13:13 am by RoGeorge »
 
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Offline bugi

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Re: waveform generator advice
« Reply #30 on: May 27, 2018, 08:52:15 am »
Again: a trigger output is pretty standard. AFAIK even the low-end Feeltech generators have this. If your scope can trigger on the width of a pulse (pretty standard) then it can also trigger on the start of a sweep.

Agreed; however, I had thought I read in one of the other threads that the low end Feeltech AWGs didn't provide a sweep trigger - at least not without some workarounds.  If that's been fixed, then great.  Not that I'm expecting to buy one but it does mean that pretty much any AWG will work for me.
At least the JDS6600 doesn't have trigger output (Feeltech's very similar competitor). In such case, one could perhaps do some trickery by making one channel output the sweep and the other to output a pulse with the same frequency as the sweep's period. (Certainly should test that, without proper synchronization the channels could e.g. drift out of sync. I can not test this idea right now, my unit currently packed away.)
 
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Offline slloyd

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Re: waveform generator advice
« Reply #31 on: August 02, 2018, 04:15:15 am »
Rigol DG1022Z is an absolute DO NOT BUY.   i have one brand new, i'm hating it.  two reasons.. arbitrary waveform generator is a POS because you can't program your waveform from front of screen, you have to connect a laptop to it and create your waveforms and then download it to the generator.  ok, this gives certain advantages like its easier to use a mouse, and probably software helps you create some fancy signals.... BUT ... what if your laptop can not communicate to generator?  do you even know what software to download?  do you think Rigol will help you solve this problem?  NOPE!!

other reason i don't like it is because i'm generating a sinusoidal waveform, 190mVpp with a 30mVpp offset.   as i decrease magnitude from 190 to 180mVpp i hear CLICK CLICK in the generator as i suppose some internal contactors are changing over to support a new range.  during this time the output has momentary outage because contactors are break before make. grrr!
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Offline Wolfgang

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Re: waveform generator advice
« Reply #32 on: August 03, 2018, 01:10:29 am »
I have several DG1062Zs (60MHz), and I like them, for the following reasons:

- Very clean output signal. Can even be used for RF work in the HF bands and 6m
- Very good modulation quality, better than some genuine RF generators
- USBTMC and SCPI support, I never had a problem communicating with this one. Who wants to type in arbitrary waveforms at the
  generator front panel ? The DG1062Z has huge record lengths, ...
- Yes, the DG1062 uses a relay-based attenuator. Its not as fast as electronic switches, but a lot more precise. I like it this way.
  Ever wondered why a lot of high-quality scope front ends, spectrum analyzers or RF generators make clicks when you change level ?
- Clean rectanges, very little overshoot, generally good signal quality up to the upper frequency limit.

Some tests regarding RF:

https://electronicprojectsforfun.wordpress.com/test-equipment/test-equipment-measurements/rf-signal-generator-am-modulation-quality/

I've not tried a Siglent, but I would recommend to try both in the aspects that have priority for you side by side.
 

Offline slloyd

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Re: waveform generator advice
« Reply #33 on: August 06, 2018, 06:47:43 pm »
Quote
what if your laptop can not communicate to generator?  do you even know what software to download?  do you think Rigol will help you solve this problem?  NOPE!!

Rigol did eventually provide some assistance.  Rigol DG1022Z works with UltraStation not UltraWave or UltraSigma.  creating your own waveform is still not easy, but it does work. 

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