Function generator - what do you use it for and what specs - Page 1
Forum section: electronics / testgear

author: nuno
author_rank: Frequent Contributor
timestamp: May 17, 2014, 12:29:40 pm
content: So, what are your specificrealuses of a function generator?What waveforms at what frequencies?At what resolutions?With what output amplitudes and offsets?And what precision/stability of frequency/offset/amplitude is important for your use?Cheers

author: eurofox
author_rank: Unknown
timestamp: May 17, 2014, 12:50:13 pm
content: I use the Siglent SDG1050, Lecroy use it as well re-branded.I love it, it does all I need, I have another generator in my Agilent MSO-X3000.DDS technology, dual-channel output. Outputs are completely independent with adjustable phase shift.125MSa/s sample rate, 14bit vertical resolution.5 types of standard output waveforms, built-in 48 arbitrary waveforms.Complete set of modulation functions: AM, FM, PM, FSK, ASK, PWM, linear/logarithmic sweep, burst.Abundant input/output: waveform output, ? Synchronous signal output, External modulation source input, 10MHz clock input, external trigger input, internal trigger output etc.Channel coupling and duplication functionBuilt-in accurate frequency counter enables user to measure frequencies up to 200MHz (single channel)Standard interfaces: USB Device, USB Host,High precision clockSupplied with powerful arbitrary editing software (EasyWave)Remote control support

author: TMM
author_rank: Frequent Contributor
timestamp: May 17, 2014, 01:05:18 pm
content: Rigol DG4062, use it mostly with 20Hz-20KHz sine waves, 10mVrms to as high as it goes for audio work. If i need a DC offset it is usually no greater than 2.5v.It's surprisingly low noise/distortion too with the 14bit DAC although i don't actually use it in noise/distortion measurements but it is a lot more convenient to quickly test circuits than having to setup a PC soundcard.Absolute precision/drift isn't very important for my uses.

author: nuno
author_rank: Frequent Contributor
timestamp: May 17, 2014, 03:38:16 pm
content: That's quite some machine you have there eurofox, but I was asking about the real use you make of it, not about FGen models and specs.

author: eurofox
author_rank: Unknown
timestamp: May 17, 2014, 03:54:56 pm
content: Quote from: nuno on May 17, 2014, 03:38:16 pmI use it in many different applications, right now I use it to drive an ultra fast pulse generator (50ps rising time).I used this week with the 2 channels to test/repair and delay plugin, it is a versatile instrument.eurofox

author: nuno
author_rank: Frequent Contributor
timestamp: May 17, 2014, 04:58:21 pm
content: And what waveforms, frequency, frequency resolution and output voltage ranges do/did you use for those tasks?

author: eurofox
author_rank: Unknown
timestamp: May 17, 2014, 05:44:22 pm
content: Quote from: nuno on May 17, 2014, 04:58:21 pmFrom 4mV to 5VPP, From 0,1Hhz to 25Mhz. Mainly square but sometimes sinus as well or pulse.Like I alredy wrote it is a very versatile instrument.When I need something above 50Mhz I have a HP sinus generator to go til 3,2Ghz.eurofox

author: Rory
author_rank: Frequent Contributor
timestamp: May 17, 2014, 06:55:32 pm
content: Among other things, my Rigol DG4062 has been used to:* Sweep filters for passband attenuation and ripple, both at audio and RF frequencies, in conjunction with an oscilloscope;* Generate windowed gated-burst waveforms for peak detector testing* Used with a 100dB attenuator, measure communications receiver sensitivity, bandwidth and AGC characteristics* Measure impulse, step response and group delay of analog and digital filters* Generate 2-tone audio at line levels for SSB transmitter output power level adjustment to minimize IMD.* Generate audio signal for opamp audio preamp testing, bandwidth characterization and gain adjustment* Measure coax lengths, as in Alan's youtube videos.The DG4062 replaced a BK Precision 3030 sweep function generator. The capabilities and specs of the DG4062 are astounding, compared to that of the old 3030.

author: Electro Fan
author_rank: Super Contributor
timestamp: May 17, 2014, 07:25:16 pm
content: Is anyone using their arbitrary generator to create pulse patterns that represent bits and bytes? Do you use the front panel or remote control software with a PC? How hard is it to construct bit by bit bytes? Do you have to click on multiple sample points to create the shape (amplitude and duration) of each pulse or can you "draw" lines (with a mouse)? Once you have made a waveform how easy it is to edit a waveform (cut, copy, and paste settings)? For example, if you wanted to generate 8 bit bytes with start and stop bits and parity bits and you wanted to create a wave form of pulses that represented the alphabet (a thru Z), would that be a lot of work or something fairly easy to do? Thanks

author: georges80
author_rank: Frequent Contributor
timestamp: May 17, 2014, 07:50:13 pm
content: I have a nice Agilent 33250A that was an ex-work freebie.My main use is to generate various pulse trains (often with sweep) to emulate sensor inputs to some of my designs.So, typically just pushing signals in the KHz range and various voltages in the ttl/cmos range. Offset sometimes to ensure the front end circuitry can handle level shifts from ground etc.Having configurable rise/fall time is nice and allows testing input conditioning circuitry (schmitt hysteresis) etc.I've also used it to generate/simulate PWM signals in the sub MHz range.So, most of my use is essentially digital like in nature so I'm barely using the 33250a's capabilities, but I got it for the right priceI have the sig gen in my newly purchased msox2000 series, so now I have a 2nd (albeit much more limited) generator.cheers,george.

author: starblue
author_rank: Newbie
timestamp: May 17, 2014, 08:48:22 pm
content: I got a 2 channel 30 MHz arb Agilent 33522B on the promo last year, and I'm very happy with it (except maybe for acoustic noise).Ostensibly it is for my current job where I simulate measurements of resistance and inductance via current pulses and resulting voltages. It's nice that you just tell it to do x, and it does x (the simulated measurements are less than 1% off. In fact, they are easier to control than real measurements).I also used it for playing with a servo, ultrasonic sensors, reverse recovery of a 1N4148 and various other stuff.Precision of sine wave amplitude is better than 0.3%, which I used to test my new DSO-X 3034A.A function generator is a must for an electronics lab, right after getting an oscilloscope.

author: nuno
author_rank: Frequent Contributor
timestamp: May 19, 2014, 09:25:44 pm
content: I was thinking if the func-gen in the Rigol 1000Z series is worth buying (some 200€ difference between the version with or without func.gen.). I don't have a specific use for a func.gen. right now, at least not something I can't do with a dozen lines of microcontroller code and a few external components.

author: Zh4ng
author_rank: Unknown
timestamp: May 20, 2014, 08:58:51 am
content: My thoughts to a function generator:How important is the waveform memory?Rigol 1000Z -> 8 MptsRigol 4062 -> 16KptsWhere I need the memory?

author: TMM
author_rank: Frequent Contributor
timestamp: May 20, 2014, 09:09:29 am
content: Quote from: Electro Fan on May 17, 2014, 07:25:16 pmI have used the DG4062 to generate the bit pattern for a 38KHz IR receiver (e.g. TV remote) for shits and giggles.Front panel ARB functionality is abysmal. I couldn't be bothered figuring out how to work Rigols PC software so i generated the bit pattern in matlab, exporting it to a WAV file and converting the WAV file to the Rigol format with the provided software. I also found that the DG4062 is incapable of performing modulation on the full length ARB (16384 samples). I believe it resamples it to 2048 or 4096 samples (i forget which) so i had to duplicate all the bits 4 or 8 times each in the ARB file so it would modulate it properly without skipping bits. Another workaround was to output the raw bitstream on one channel and loop it back into the analog modulation input on the back, then have it output the modulated signal on the second channel.

author: Fsck
author_rank: Super Contributor
timestamp: May 20, 2014, 09:22:45 am
content: Quote from: Zh4ng on May 20, 2014, 08:58:51 amthe memory is for the number of points for generating an arbitrary waveform (per the name of the equipment)more points = more detail.

author: jpb
author_rank: Super Contributor
timestamp: May 20, 2014, 10:00:54 am
content: Quote from: TMM on May 20, 2014, 09:09:29 amThat is interesting. After reading your post I looked at the manual which states:Arb: when arbitrary waveform is selected as modulating waveform, thegenerator would limit the waveform length to 2kpts automatically.It does seem a bit restrictive especially at lowish frequencies.

author: Mr. Coffee
author_rank: Regular Contributor
timestamp: May 21, 2014, 02:14:08 pm
content: Ascel AE20125, crystal controlled digital 0.1 to 10 MHz, sine, triangle, and squarewave with sweep and DC offset ability.Sine signal injection in vintage radio receivers, <10 MHz.Test signal injection to test homebrew amplifier frequency response or for measuring instrument calibration, 1 kHz to 4-5 MHz.Square waves for testing audio amplifier response, <100 kHz.