We’ve built our own based on AD chips like the AD5932 and relatives. These are a few dollars per chip and the $$ tracks top frequency (more or less). Some have 1.5 GHz outputs for ~$100.
http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad5932/products/product.html These cheaper boxes are likely packaged AD chips, i.e. they added power supply, BNC output, LCD panel etc. In other words, even if the thing really breaks and stops working, you could drop in another $5 chip and use the front end hardware for your own device. -Andy -- Andrew M.C. Dawes Associate Professor of Physics Pacific University amcdawes.com On August 1, 2014 at 5:24:44 AM, Paul Stoffregen ([email protected]<mailto:[email protected]>) wrote: Also I noticed that the Rigol model he mentioned comes with an optional function generator for $250 more [Model DS1074Z-S] which might save money over buying one separately. Something to consider with built-in extras is the shared user interface. On a scope, you'll access this stuff using the menus, which are already packed with tons of scope features. Budget scopes have lots of crafty ways to share knobs, like only 1 set of vertical controls among all channels & math. It usually works pretty well, with only minor inconvenience for saving a lot of $$$, but those menus do tend to get pretty crowded. With a dedicated function gen, you get a big knob to vary the amplitude and/or frequency, buttons to change waveform and settings, and usually a display that shows what it's doing. The controls are optimized for the function generator features, which makes using it quite a bit easier and more natural than a function generator shoehorned into the scope's menu system. If it were under $100, of course the decision would be easy. There are many dedicated DDS function generators in the $250 to $350 range, and a lot of used gear well under $250. If you only need basic signals at modest frequency and you don't need the frequency stability of DDS, there are a lot of old/used but good quality analog function generators under $70. There's also some really cheap DDS stuff out there now, which might actually work? If anyone actually takes a chance buying these, or already has one, I'd be really curious to play with it sometime at a Monday meetup. http://www.ebay.com/itm/10MHz-DDS-Function-Signal-Generator-Carrier-Debugging-Source-Frequency-Counter-/281310662043?pt=LH_DefaultDomain_0&hash=item417f6c0d9b http://www.ebay.com/itm/2MHz-Dual-Channel-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-/111407197529?pt=LH_DefaultDomain_0&hash=item19f062ed59 http://www.ebay.com/itm/2MHz-DDS-Function-Signal-Generator-Frequency-Counter-Square-Wave-Sweep-BNC-TTL-/281295638078?pt=LH_DefaultDomain_0&hash=item417e86ce3e# _______________________________________________ dorkbotpdx-blabber mailing list [email protected] http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
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