Ken, a very interesting system. It seems that leaving the amp outputting 1 GHz longer than necessary won't hurt. I believe the unterminated horn will present a reactive load and should not dissipate the chamber energy. If an oscilloscope was connected to another 1 GHz antenna (even a dipole) one could observe the chamber "charging" and then know how long to gate the signal on. Dave Cuthbert Micron Technology The pulse is a modulation waveform. At say 1 GHz the signal source is gated on and off for a duration of 1 us at a 1 kHz rate. The pulse rise/fall-time is limited by the rate of change associated with the microwave frequency. I think understand what you are saying about the transmit antenna, that if you could switch it off the signal source then it wouldn't load the chamber "Q." I don't think that is an issue in this case, but it is an interesting idea for a low duty cycle modulation like this. I really don't have a feel for what kind of load an unterminated or shorted horn would present to the field. Do you? > From: [email protected] > Reply-To: [email protected] > Date: Tue, 29 Jul 2003 09:49:12 -0600 > To: <[email protected]>, <[email protected]> > Subject: RE: pulse modulation in reverb chambers > > > Ken, > > do you mean you pulse an antenna with a square wave at some specific > repetition rate? If so, The pulse rise time and duration can be selected to > contain the frequency components you want. I think that if the pulse remains > on two long, the generator will act as a 50 ohm load and absorb energy from > the chamber. Switching the generator from a 50 ohm state to a high-Z or low-Z > state could be beneficial. > > Dave Cuthbert > Micron Technology This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
