EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: 6E5 on February 19, 2014, 02:03:36 am
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Hi,
Just a bit of introduction-
I am an electronics hobbyist of 5 years. I've been restoring (fooling around) around with old vacuum tube equipment, such as radios, test equipment, tvs, for most of the time, but I've been getting more into modern solid state electronics. Part of that has been watching Dave's videos and watching him getting excited (and progressively higher pitched) with all these transistor things.
In the coming months I will be purchasing a digital function generator for calibrating equipment and project testing.
I'm looking for a function generator that can provide sine, square, triangle, and sawtooth waveforms. A limit of several mHz would be satisfactory, however 10's of mHz would be nice)
Previous Recommendations-
I'm part of the Antique Radio Forum (ARF), and they recommended me a hp 3325. That is Sine- 20mHz, Square-10mHz, and triangle/sawtooth-10kHz. The sawtooth and triangle limit is frankly too low for me. Also, the $300-500 price for a working one is a bit too steep.
In summary, I need an accurate, reliable generator with sine, square, triangle, and sawtooth waveforms which is in the $200 or below range. (Preferably below...)
It doesn't have to be new, a used 70's or 80's kit would suit me just fine. (I much prefer the old hp or tektronix equipment to Rigol or other Chinese guys)
Regards,
Paul
Scroll down for my 1/19 post that has my current question.
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I'm part of the Antique Radio Forum (ARF), and they recommended me a hp 3325. That is Sine- 20mHz, Square-10mHz, and triangle/sawtooth-10kHz. The sawtooth and triangle limit is frankly too low for me. Also, the $300-500 price for a working one is a bit too steep.
Well, the 3325 is actually an analog function generator, which is part of why it has that limitation. The triangle and sawtooth functions are supposed to be high linearity waveforms. The only digital part is the control panel, which sets the frequency via PLL. (It does GPIB as well, which can be useful.)
Obviously if the low frequency triangle/sawtooth is a problem it's not the right device for you - but as for the price, you really should be able to score one for a bit over $100.
You should set your country in your profile - I had to look at your "New Member" post to figure out that you were in the US and my "bit over $100" would be accurate...
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3325A fly by on ebay for 100 to 150 $ regularly.
8111 is another option. but frequency adjustment is 3 digits only. the 3325 is a VERy good machine.
you could look at a 3324 as well.
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Not quite $200, but still under $300 delivered
http://www.ebay.com/itm/ATTEN-ATF20B-DDS-FUNCTION-WAVEFORM-GENERATOR-20MHZ-100MSa-s-1-year-warranty-/290879327522?pt=LH_DefaultDomain_0&hash=item43b9c24d22 (http://www.ebay.com/itm/ATTEN-ATF20B-DDS-FUNCTION-WAVEFORM-GENERATOR-20MHZ-100MSa-s-1-year-warranty-/290879327522?pt=LH_DefaultDomain_0&hash=item43b9c24d22)
A modern function gen like this is very powerful and flexible.
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Hi,
Thank you for the speedy reply.
Dave- As much as I love your reviews, I have to admit, I really don't like the plastic Chinese equipment. I feel that the old US made equipment from a few decades ago have more quality and, well, love... However, that Atten for that price is very tempting.
c4757p and free_electron- That is some good news if I can get that hp equipment for under $150, for that price I could certainly live with the 3325's 10kHz bandwidth. Perhaps I was just looking at the wrong time.
How would you compare the reliability and ruggedness of the newer Chinese generators to the old hp generators?
My final question is, sorry for so many of them, what is the advantage of these modern Chinese function generators to the old hp equipment? I'm not really concerned with options such as more memory or OSHA regulations, I'm really in the market for a generator where you select a waveform, punch in some frequency, duty cycle, amplitude, and offset characteristics, and you're good to go.
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c4757p and free_electron- That is some good news if I can get that hp equipment for under $150, for that price I could certainly live with the 3325's 10kHz bandwidth. Perhaps I was just looking at the wrong time.
Here's one (http://www.ebay.com/itm/HP-3325a-function-generator-Sweep-genrator-HP-generator-SYNTHESIZED-/121278079257?pt=LH_DefaultDomain_0&hash=item1c3cbca119) starting at $130, though it's an auction with 5 days left
Here's another for $169 BIN (http://www.ebay.com/itm/HP-Hewlett-Packard-3325A-Synthesizer-Function-Generator-T35441-/281255929943?pt=LH_DefaultDomain_0&hash=item417c28e857)
Keep an eye out and you'll find one cheaper. I got mine for $120 delivered.
How would you compare the reliability and ruggedness of the newer Chinese generators to the old hp generators?
I'll put it this way - the 3325As are all around 40 years old and still work.
Might need a couple capacitors replaced, and mine had faulty optocouplers in the GPIB circuit, but that's it.
The Atten has many more features, though - do you need them?
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Hi C,
I've been looking at reviews for the Atten, and I haven't heard good things, especially from this forum. Mainly the RS232 and USB are fake, bad software, only sine wave is supported to 20mHz, and other questionable issues. The competitor Rigol DG1022 also has a list of problems.
In summary, the HP 3324/3325, 40 years old and long outdated, is the best value for this guy.
The service literature is quite dense, can anyone tell me the basic difference between the 3324, 3325, 3314, and 3336? I see that the 3325 has a LED display, 3324 goes with a VFD, the 3314 has the great Easter egg, and the 3336 looks very similar to the 3325.
Thanks guys,
Paul
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3314 is the predecessor for the 3324. 3324 uses a different synthesizer for the frequency ( fractional-n) where the 3314 is a simple digital cascade driving a pll.
the fractional-n allows for whacky frequencies like 1.2345678901MHz. ( and it WILL be spot on ! if you drive it from a correct 10Mhz reference )
3325 is a simplified 3324 in the sense it does not have the hopping / stepping and other crazy stuff you can do with a 3324.
that being said : the hopping/stepping in the 3324 is a bitch to program through the frontpanel. it is supposed to be done through GPIB. there was a special program running on the old 9000 or 150 series HP workstations made especially for that purpose. but the program is unfindable and those machines are even more unfindable.
3336 is sinewave only.
3314 is old and 3 digit frequency adjustable only
3324 is the most powerful machine in terms of stuff you can do with it. its an upgraded 3314 with more digits and more functions. it uses the same signal generation block as the 3314. only the control is different.
3325 is a functional strip down but it has an option to make up to 40 volts peak peak. again same signal generation block as 3314
3336 is a sinewave only.
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How would you compare the reliability and ruggedness of the newer Chinese generators to the old hp generators?
My final question is, sorry for so many of them, what is the advantage of these modern Chinese function generators to the old hp equipment? I'm not really concerned with options such as more memory or OSHA regulations, I'm really in the market for a generator where you select a waveform, punch in some frequency, duty cycle, amplitude, and offset characteristics, and you're good to go.
I can't comment on Chinese signal generators since I have no experience with those, but I do own a HP3325A. As far as I know there is no way to specify the duty cycle (if it is possible I really would like to know how). It also has some odd limitations w.r.t. DC offsets. It doesn't support frequency modulation. Keyboard entry is great if all you want is a signal with a specific frequency and amplitude, but when experimenting I do miss knobs to adjust frequency, amplitude and DC offset.
The unit I got (for about €100,-) had some issues with the keyboard (springs) and one of the attenuator relays not working reliably. These seem to be common problems with this model. Those issue are fixable but are something to be aware of. The fan is annoyingly loud, but that might be due to the age of my unit (30+ years). Another thing to keep in mind is that the HP3325A is huge (very deep) compared to its contemporary counterparts, if you don't have room to spare or nice 19" rack this might be an issue.
As a function gen I find the HP3325A rather limited, but I guess it is fine if all you need is a symmetrical sine- or square wave signal with a precise frequency and amplitude. I expect that its sine wave output is also a bit cleaner than that of those signal generators that play samples from memory. Other than that I see no compelling reason to go for a HP3325A.
The manual of the HP3325A can be found online (IIRC I got it from the Agilient site), I recommend you take a look at it to see if it suits your needs.
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Heck...you could just pick up a 20Mhz BK 4040a off ebay. Sure, it's not digital, but it has many useful functions one most often uses and, in my experience, they are reliable and stable. I have an older U.S. made model and the thing is working perfectly fine and is still tenaciously holding it's calibration.
If you want a really nice compact generator that doesn't eat up too much bench space take a look at something like a HP 3310A/3310B. Sweet little 5Mhz hands-on working man's generator.
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This thread is 3 years out of date so some unashamed updating required.
https://www.eevblog.com/forum/testgear/the-siglent-sdg2042x-thread/ (https://www.eevblog.com/forum/testgear/the-siglent-sdg2042x-thread/)
And new kid on the block with both Sine and Square to max model frequency:
https://www.eevblog.com/forum/testgear/siglent-sdg1000x-waveform-generators/ (https://www.eevblog.com/forum/testgear/siglent-sdg1000x-waveform-generators/)