General > General Technical Chat
NOT re-inventing the 'Electronic' Wheel !!
GlennSprigg:
MOST of us 'hobbyists' have/use Budget equipment, as opposed to some of the Professionals here.
I for one, am starting again in my old age, after loosing all my test equipment many decades ago !!
A LOT of us (?) may/do have such cheap devices like the "FG-100 DDS Function Generator", for $24 !
As an example, that's all cute, well & good! However, some of us want say 'Amplitude-Modulation' as
well, amongst other things! Well, if you are working on old radios etc, and want to tune 'IF' (intermediate
frequencies like 455-khz etc), then you can pay many hundreds if not thousands of dollars for specialized
test-equipment. So for just ONE example, how can we simply add 'Amplitude-Modulation' to our signal!?
I reviewed numerous methods, involving relatively complex circuit designs, until I found out about the...
AD633 Chip!! It's all done for you!!!....
This is but ONE of it's functions/uses(modes), requiring virtually NO other circuitry! The above image was
taken from the Spec/Data sheet for that chip, which varies from about $1 to $2. Spec-Sheet...
https://www.tme.eu/Document/ce5356ac4efb480c752b9e53289e2634/AD633ARZ-Analog-Devices.pdf
Input your 'Modulation' tone, (or voice!) along with the 'Carrier' and you are home & hosed!!
See the likes of....
for a simplistic demo. I need to stop reinventing the wheel, and use such simple & cheap devices, in
conjunction to what I have, without needing lots of money!! ;D
With just a LITTLE bit of fore-thought, we can do SO much more, with what we have :-+
tom66:
Interesting. But there are simpler ways with not too much expense. My £60 FY6800 supports AM and FM modulation too, which can either be input through an external terminal (VCO) or generated internally. My GW Instek AFG-2105 also supports this. This is a common feature on many signal generators, as you point out it is commonly needed.
GlennSprigg:
--- Quote from: tom66 on June 29, 2020, 12:53:27 pm ---Interesting. But there are simpler ways with not too much expense. My £60 FY6800 supports AM and FM modulation too, which can either be input through an external terminal (VCO) or generated internally. My GW Instek AFG-2105 also supports this. This is a common feature on many signal generators, as you point out it is commonly needed.
--- End quote ---
I think I am aiming this at people with basic cheap equipment at hand, and how easy it is to
modify for more advanced features. Cost, being the main point. Thank you !
RJSV:
Hi there, I also enjoy evaluating cheapo solutions, although I (barely) can afford $35 parts orders now and then.
For a high speed signal, a 'drug store's toy hand-held video game can provide signals. Complex audio but also if you can isolate a high impedance probe there will be a HF clock found on the crystal. You can cut away portions of plastic case. Crystal might only provide low voltage etc. Expect 8 ,MHz, maybe.
You get a case / speaker / battery holder / power switch. AND my favorite 'slogon': "You get a couple of free batteries, in the deal.
P.S. Steer clear of the 'educational' toys: often they have keyboard integrated into the case front.
Ages 3+, that'd be me!
ebastler:
Glenn -- where did you see the AD633 for $1 to $2? Wherever I look it is more than $10. By the time you have it powered, added input/output amps, connectors, power supply... it will easily have cost you $30.
Also, your suggestion to add an AD633 to an existing single-channel signal generator seems to be lacking the second channel? Wouldn't you want one channel to provide the carrier, and a second channel to provide the modulation signal in most applications?
I am with tom66 here: You might want to consider starting over with a dual channel signal generator. Even a low-cost one like the FY6800 will give you much more functionality, and a much handier package, than a homegrown add-on to a single channel unit.
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