Author Topic: My first Function Generator and other bits  (Read 1835 times)

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Offline NivagSwerdna

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My first Function Generator and other bits
« on: January 19, 2016, 07:41:57 pm »
Having watched a number of youtube videos I think the time has come to buy myself a function generator!  Specifically my experience of filters etc to date has been theoretical or via spice etc but I think it would be interesting to do some experimentation in the real world.  I'm a hobbyist only but do have a small budget for toys.

I'm interested in a generator that can sweep so I can put a variable frequency into a test circuit and then graph the response on my Rigol scope.

Although I'm not planning on breaking any of my radio equipment (I do dabble in Ham radio) just yet I was thinking that having a generator that could sweep around 10.7MHz might be a good thing so I'm looking at something that can go up to say 20MHz?

The "Siglent SDG1020 Arbitrary Function Generator" is about at the limit of my budget.... would this be appropriate?  Quite like the idea of being able to have AM, FM modulations.

Also... In order to graph the output of my filter circuit under test versus the swept frequency do I need a "Demodulator Probe"?  No idea what one of those is... and I'm surprised that there aren't many references to them??

I've seen videos of very fancy signal generators that have 'markers'... is that something that I can do with the SDG1020, or more specifically can I use it to generate a specific frequency to act as a marker to show me where the peak of the response is?

Please interpret this question bearing in mind I have no idea about any of this stuff!

Thanks in advance
 

Online tggzzz

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Re: My first Function Generator and other bits
« Reply #1 on: January 19, 2016, 08:00:44 pm »
General advice: work out what you need to achieve or want to do. For example, measure a filter's amplitude/phase/frequency response between f1 and f2 as a function of signal level between V1 and V2.

Work out the theory of what you need to do in order to achieve it.

Then think of a way to do it, and what equipment you need in order to achieve it.

Bonus points for using whatever you already have in a new imaginative way.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Offline NivagSwerdna

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Re: My first Function Generator and other bits
« Reply #2 on: January 20, 2016, 12:24:09 am »
I want to create Bode plots of filter stages just like in EEVblog #396 - Bode Plotting on Your Osciloscope
 

Online tggzzz

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There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline NivagSwerdna

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Re: My first Function Generator and other bits
« Reply #4 on: January 20, 2016, 08:19:05 am »
I looked at EBAY and it seems to have a huge spread of devices since technology has moved on so far over the decades. The majority of devices reported by that search don't sweep so I discount them for practical reasons (life is too short to be constantly adjusting).  I'm focusing on a signal generator that can sweep, has a good sync output, and has a max frequency of at least 15MHz
 

Online tautech

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Re: My first Function Generator and other bits
« Reply #5 on: January 20, 2016, 08:29:56 am »
Avid Rabid Hobbyist
 

Offline NivagSwerdna

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Re: My first Function Generator and other bits
« Reply #6 on: January 20, 2016, 11:05:12 am »
Thanks for the link.  I hadn't seen that thread and am now reading my way through it...  :)
 


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