HP 3314A or HP 8116A? - Page 1
Forum section: electronics / testgear

author: Mandelbrot
author_rank: Regular Contributor
timestamp: February 03, 2014, 03:07:34 am
content: Hello,I'm going to a silent auction tomorrow at a local science and technology company. Among the large number of crazy lab devices (they had an electron microscope on auction a while ago) they have an HP 8116A and four HP 3314A function generators. I don't own a function generator, and I figured I could get a good deal on one of these. Besides the frequency range I don't know the real differences between the two.I will likely bid on both and it's likely I can get a great deal considering I got a Tek 2225 with a fancy scope lab cart with a drawer full of about 15 miscellaneous scope probes for $100 a few months back.My real question, if one of you with much more experience than me was in my same situation, which one would you rather have and why?

author: edavid
author_rank: Super Contributor
timestamp: February 03, 2014, 04:32:46 am
content: Working 8116As are worth a lot, but they usually die because one of the HP custom ICs fails. So, I wouldn't buy it unless you know it powers up with no error code.HP 3314As are complex, but more likely to be repairable.

author: Mandelbrot
author_rank: Regular Contributor
timestamp: February 03, 2014, 04:46:37 am
content: Thanks edavid! The Tek 2225 I bought from one of these sales before was recently calibrated and operated dead on the first time without any tweaking. This company takes pretty good care of their instruments! It's good to know that the 3314A is more repairable though because I am much less experienced than the lab engineers that previously used the function generator. I know that the 8116A is also a pulse generator, but I don't know how much I should take this into consideration. The first thing I'll probably do with it is use it to generate AM signals to test a demodulator I'm working on for a design class I'm taking, but it seems like both will be able to do this. The HP 3314A was already the one I was preferring because I like the adjustment knob better than the buttons on the 8116A.

author: edavid
author_rank: Super Contributor
timestamp: February 03, 2014, 05:02:52 am
content: The HP 3314A can be used as a pulse generator also, but I think only up to 2MHz.

author: free_electron
author_rank: Super Contributor
timestamp: February 03, 2014, 07:31:21 am
content: the 3314 has much finer control over frequency. the 8116 only has 3 digits for frequency setting. while the 3314 has 12 …drawback of the 3314 is that it cannot make triangle or square waves faster than 1MHz. the 8116 goes all the way to 50MHz.if you are after 8116 make sure they have option 001. the ones that dont have option one have a couple of butrtons missing on the first row.the ones with option 001have all buttons. you can not install this afterwards.8116 and 3114 both use custom chips. the 8116 can be a bitch to repair. frequently the asics die and there is no replacement

author: nctnico
author_rank: Super Contributor
timestamp: February 03, 2014, 12:27:17 pm
content: @free_electron: you are mistaken. The 3314A has 4 digits. The sweep span is limited because the oscillator has several bands. The 3314A is basically an RC oscillator with a PLL to lock it to a frequency.

author: edavid
author_rank: Super Contributor
timestamp: February 03, 2014, 05:46:37 pm
content: @free_electron, you must be thinking of a different product, the 3314A goes to 20MHz for sine/square/triangle.@nctnico, isn't the 8116A the RC oscillator, and the 3314A a DDS/AWG?

author: nctnico
author_rank: Super Contributor
timestamp: February 03, 2014, 10:35:57 pm
content: No, the 3314A is also an RC oscillator (I used to have one). The 3314A uses a adjustable current source to make a triangle wave with several (switchable) capacitors to cover a wide range of frequencies. This triangle wave is 'wave shaped' into a sine wave for sine output. So yes it does triangle and square to 20MHz. A nice to have option on the 3314A is the 3X output which can output signals up to 30Vpp into a higg impedance load. The problem I had with mine was that the read-relays got sticky and needed replacement. All in all the 3314A has a neat back of tricks but I'm much happier with my Siglent SDG1010I wouldn't spend too much on either function generators.