Hi All, I just discovered another company that makes similar RF generators - Wind Freak Technologies (http://www.windfreaktech.com). They offer two models, one similar to the reviewed product above and one "deluxe" model that includes AM and pulse modulation. I'll try to get my hands on these models for review purposes and report back. One thing that struck me was the much improved user interface, based on National Instruments' LabView.
While the price for the deluxe model is considerably higher ($599), the fact it offers AM modulation (up to 5 kHz and 100%) should be attractive for those wishing to perform radiated immunity pre-compliance testing. Ken _______________________ Ken Wyatt Wyatt Technical Services LLC k...@emc-seminars.com www.emc-seminars.com Phone: (719) 310-5418 On Nov 4, 2013, at 9:19 AM, don_borow...@selinc.com wrote: > Probably the easiest way to add amplitude modulation would be to use a couple > of low capacitance (small signal) diodes -- one in series with the output, > and a second one following the first one, shunted to ground. A DC return to > ground at the output of the signal generator is needed. The signal generator > may already have such a DC return. If not, add a DC return via a choke (or > even a resistor, about 500 ohms). > > The two diodes are wired in series (cathode to anode connection). Connect the > cathode of one diode to the RF output of the signal generator. The anode of > the other diode goes to ground. Feed the audio signal into the junction of > the two diodes via a resistor, 500 ohms or larger. A choke could be added if > desired to reduce RF loss a bit. Also from this same point, pull off the > modulated RF output through a capacitor (to decouple the audio). Feed enough > audio (bipolar voltage) to get 10 to 20 mA of current through the diodes on > the peaks. > > The resulting modulation will not be pretty. It will be more like square wave > modulation. The modulation depth will be very close to 100%. Harmonics of the > RF may rise somewhat. But since we want to do radiated immunity testing, a > "dirty" signal is not necessarily a bad thing. > > Side note: If you are fortunate enough to have some PIN diodes laying around, > use them. You will get more linear modulation and lower RF harmonic > generation. > > Donald Borowski > Senior EMC Compliance Engineer > Schweitzer Engineering Labs > Pullman, WA, USA > > > > From: Ken Wyatt <k...@emc-seminars.com> > To: EMC-PSTC@LISTSERV.IEEE.ORG > Date: 11/04/2013 07:48 AM > Subject: Re: [PSES] Inexpensive RF generator > > > > Hi Scott, > > Yup, you're right. I don't see any easy way of modulating the RF on this > generator. I'll ask the designer if he can think of a way and get back to the > group. > > Ken > _______________________ > Kenneth Wyatt > Wyatt Technical Services LLC > 56 Aspen Dr. > Woodland Park, CO > > Phone: (719) 310-5418 / Toll Free: (877) 443-9275 > > Email Me! | Web Site | Blog > The EMC Blog (T&M World) > Subscribe to Newsletter > Connect with me on LinkedIn > > On Nov 4, 2013, at 8:34 AM, S Drysdale <sdd...@gmail.com> wrote: > > Hi Ken, > > In my experience, a device may sometimes pass CW, but fail when modulated. > Can you advise an economic way to modulate the RF? > > Best Regards, > Scott Drysdale > OOO - Own Opinions only > > > > > On Sat, Nov 2, 2013 at 8:10 PM, Ken Wyatt <k...@emc-seminars.com> wrote: > Hi All, > > I just uploaded a new posting - "Review: inexpensive RF generator" > > http://www.edn.com/electronics-blogs/the-emc-blog/4423710/Review--inexpensive-RF-generator > > > Thought this might be helpful for some applications. > > Cheers, Ken > > _______________________ > Ken Wyatt > Wyatt Technical Services LLC > k...@emc-seminars.com > www.emc-seminars.com > Phone: (719) 310-5418 > > - > > David Heald <dhe...@gmail.com> > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <emc-p...@ieee.org> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <emcp...@radiusnorth.net> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
