Function Generator

[pwdrive]

I've no experience of these things.

Question, there's a few that go up to 30 Mhz and beyond with sine wave output at a decent voltage, they seem to be digital jobies, If the output was to beat with a fixed frequency would frequency steps be heard when tuning to beat or is there some sort of algorithm that smooths that out...this might be a hit and miss question

Lawrence.

[ppppenguin]

Function generator is usually applied to kit that can do sine/square/triangle outputs. Normally at relatively low frequencies. An arbitrary function generator can synthesise almost any waveform within its limits.

If you want good quality sine waves then you need a signal generator. These can be very simple or very complex. Pure analogue, conventional synthesised or direct digital synthesis.

An example of a very high quality synthesised geenrator is the tracking generator in my HP network analyser. 0-500MHz. I can set the frequency with a precision of a tiny fraction of a Hz. The absolute accuracy is better than 1ppm though I could improve that by using an external 10MHz reference lock to GPS.

What are you trying to do?

[pwdrive]

I want to do some general experimentation, 0 to 30 Mhz, frequencies above 30 Mhz would not be of any interest to me.

Conventional valve RF mixers, single balanced RF mixers, double balanced RF mixers, RF amps, general RF work up to 30 Mhz.

I've been looking at one of these:

https://www.rigol-uk.co.uk/Rigol-DG1032Z...q80AVLLKZo

Not saying I'm going to put my name to one as yet 'cos I can't afford it at the moment but it seems quite versatile, as I understand it two independent outputs, modulation facilities of various modes, sweep, various other inputs/outputs probably accurate enough for what I need.

Just after general pro's and con's comments on these types of generators and the one in the link if anyone has one of them.

Also need stuff that has a small bench footprint as the house has been reconfigured  

Lawrence.

[pwdrive]

Out of interest here's the manual for the DG1032z:

http://www.batronix.com/pdf/Rigol/UserGu...ide_EN.pdf

Lawrence.

[ppppenguin]

As usual with Rigol that's a lot of kit for your money. If you don't need anything about 30MHz that's the only generator you'll ever need unless you're doing ultra high performance audio.

[Terry]

That looks like a very expensive sledgehammer to crack a very small nut!

Surely all you need is an ordinary signal generator, although I doubt you'll easily find one that goes down to DC as per your specification!

What is your realistic lower limit? If you want to do some audio work as well - but not listed in your requirements - a separate low cost AF generator would be better, surely?

I'd look again but for RF signal generators this time. You might find exactly what you are looking for at a much lower price, especially if you are prepared to accept a used unit.

[pwdrive]

Yes, I can but drool at the moment, from what I understand in the book of words it does suppressed carrier as well albeit double side band.
I might order up that Tenma (Instek GOS 630FC) 30 Mhz analog 'scope this week from Farnell, looking at the price and stock levels it looks like they might have been lumbered in the rush for digital 'scope demand:

http://uk.farnell.com/tenma/72-6802/osci...dp/1563801

Lawrence.

[ppppenguin]

Why buy one of those scopes at 220+VAT when for another 40+VAT you can have the Rigol DS1054Z with hugely greater capability.

One nice thing about the Rigol FG is the ability to set very precise frequencies. This may or may not be relevant to Lawrence's experiments. When I use my Network analyser as a SG i've sometimes set very low frequncy beats against precision sources. Also used it for investigating what happens to xtal PLLs when the input frequency shifts by a few Hz in several MHz. Try doing that with an old style analogue SG

[pwdrive]

Yes, really want to avoid old style SG, the stability and accuracy are not always that good, I like the fact that that Rigol one appears to have two independent channel outputs, that can be phase aligned or shifted, Dave's EEV blog shows him using the trigger output from a Rigol FG to display filter response on a Agilent 'scope, one advantage of that scope is that the vertical scale can be switched from linear to log to give a more realistic representation of filter response:

https://www.youtube.com/watch?v=uMH2hGvqhlE

Lawrence.